Bulletin


[LLINOIS NATURAL HISTORY SURVEY

Bulletin Printed by Authority of

the State of Illinois

Food Habits

of Migratory Ducks

in Illinois

tIARRY G. ANDERSON

ITATE OF ILLINOIS* Willum G. Stratton, Governor

)EPARTMENT OF REGISTRATION AND EDUCATION • Vera M. Binks. Director

sfATURAL HISTORY SURVEY DIVISION • Harlow B. Mills, Chief

n..^ o„ ,--.^ NATURAL





ILLINOIS NATURAL HISTORY SURVEY

Bulletin

Volume 27, Article 4 „•.,.,-.Printed by Authority of

August, 1959 the State of Illinois

Food Habits

of Migratory Ducks

in Illinois

HARRY G. ANDERSON

STATE OF ILLINOIS* William G. Stratton, Governor

DEPARTMENT OF REGISTRATION AND EDUCATION • Vera M. Binks, Director

NATURAL HISTORY SURVEY DIVISION • Harlow B. Mills, Chief

Urbana Illinois



STATE OF
William G Stba

i LL I N O I S

I TON, (Ji-v/inur

DEPARTMENT OF REGISTRATION AND EDUCATION
Ve«a M. BiNKt, DirtctoT

BOARD OF NATURAL RESOURCES AND CONSERVATION
VenA M. BiNKi, Chairman; A. E. Emkhsos, TIlD., Hiuloiy ; Wai.tek H. Newhouse, Ph.D., Geoloiy; Roger Adami,
Ph.D., D.Sc, Chtmntry; Robekt H. Anueiiso.n, B.S.C.E., En'mffring. W. L. EvEmn, E.E.. Ph.D., Urprtientint tht
Hrtsident o/ the IJ niveriily oj Illinois; Delyte W. Mokris, Ph.D.. I' o.tlent of Southern Jllinoti Univeriity

NATURAL HISTORY SURVEY DIVISION, Urbona, Illinois

SCIENTIFIC AND TECHNICAL STAFF
Hariow B. Milis. Ph D., Chiel

Bes(ie B. East, M.S., Atsistant to the Chief

Section of Economic Entomology
Georl.l C. UtcittR. Ph.D., Principal Sfientiit and Head
J. H. BlcoER, M.S.. Entomoloiist
L. L. English. Ph D., Entomologiit
WiLLit N. Brlicl, Ph.D., Associate Entomoloiiit
Norman Gannon, Ph.D., Associate Entomologist
W. tl. Llcilmann, Ph.D., Associate Entomologist
Rohalo H. Meyer, M.S., Assistant Entomologist
John D. Paschke, Ph.D., Assistant Entomologist
John P. Kramer, Ph.D.. Assistant Entomologist
Robert Snetiincer, M.S., Field Assistant
Carol Morgan, B.S., Laboratory Assistant
Eugene W. Bravi, \LS., Research Assistant
Richard B. Dysart, B.S., Technical Assistant
Reginald Roberts, A.B., Technical Assistant

James W. Sanford, B.S., Technical Assistant
Earl Stadelbacher, B.S., Technical Assistant

Sue E. Watkins, Technical Assistant

\\. B. Petty, Ph.D., Extension Specialist in Entomology*
Stevenson Moore, III, Ph.D., Extension Specialist in

Entomology*
Zenas B. Noon, Jr., M.S., Research Assistant*
Clarence E. Whiie, B.S., Research Assistant*

John Arthur Lowe, M.S., Research Assistant*

J. David Hoepman, B.S., Research Assistant*

Carlos A. White, B.S., Research Assistant*

Roy E. McLaughlin, B.S., Research Assistant*
CosTAS KousKOLEKAS, M.S., Research Assistant*
I^uiSE ZiNGRONE, B.S., Research Assistant*

Mary E. Mamn, R.N., Research Assistant*

Section of Faunistic Surveys and Insect Identification

H. H. Ross, Ph.D., Systematic Entomologist and Head
MiLioN W. Sanderson, Ph.D., Taxonomist
Lewis J. Stannard, Jr., Ph.D., Associate Taxonomist
Philip W. Smith, Ph.D., Associate Taxonomist
Leonora K. Gloyd, M.S.. Assistant Taxonomist
H. B. Cunningham. M.S.. Assistant Taxonomist
Edward L. Mockford, M.S., Technical Assistant
Thelma H. Oversireet. Technical Assistant

Section of Aquatic Biology
George W. Bennett, Ph.D., Aquatic Biologist and Head
William C. Starrett. J'h.D., Aquatic Biologist

R. W. Larimore, Ph.D., Aquatic Biologist

David H. Buck, Ph.D., Associate Aquatic Biologist
Robert C. Hiltibran, Ph.D., Associate Biochemist
Donald F. Hansen, Ph.D., Assistant Aquatic Biologist
William F. Childers, M.S.. Assistant Aquatic Biologist
Marifran Martin, Technint Assistant

John C. Cralley, B.S., Field Assistant

Section of Aquatic Biology—continued
Kkhahu E. Bass, Field Assistant
Robert D. Crompton, Field Assistant
Arnold W. Fritz, B.S., Field Assistant*
1)avii> J. McfiiNTY, Field Auiitant*

Section of Applied Botany and Plant Pathology
J. Cedric Carter, Ph.D.. Plant Pathologist and Head
j. L. Forsberg, Ph.D., Plant Pathologist
G. H. Boewe. M.S., Associate Botanist
Robert A. Evers, Ph.D., Associate Botanist
RoBhRT Dan Neely. Ph.D., Associate Plant Pathologist
v.. B. IIimm.uk. Ph.D.. Aiujiiate Plant Pathologist
Walter Hartstirn, Ph.D., Assistant Plant Pathologist
D. F. Schoeneweiss, Ph.D.. Assistant Plant Pathologist
Rovenia F. Fitz-Gerald, B.A., Technical Assistant

Section of Wildlife Research
Thomas G. Scott, Ph.D., Game Specialist and Head
Ralph E. Yeatter, Ph.D., Game Specialist
Carl O. Mohr. Ph.D., Game Specialist

F. C. Bellrose, B.S., Game Specialist

H. C. Hanson, Ph.D., Associate Game Specialist
Richard R. Graber, Ph.D., Associate Ifildlife Speciedist
Ronald F. Labisey, M.S., Assistant Wildlife Specialist
Frances D. Robbins, B.A.. Technical Assistant
Howard Crum, Jr., Field Assistant
John L. Roseberry, B.S., Technical Assistant
Rexford D. Lord, D.Sc, Project Leader*
Frederick Greeley, Ph.D., Project Leader*
Glen C. Sanderson, M.A., Project Leader*
Jack A. Ellis, M.S., Assistant Project Leader*
Thomas R. B. Barr, M.V.Sc, M.R.C.V.S., Research

Assistant*
Bobbie Joe Verts, M.S., Field Mammalogist'
Erwin W. Pearson, M.S.. Field Mammalogist*
Keith P. Dauphin, Assistant Laboratory Attendant*
Gary P. Imel, Assistant Laboratory Attendant*

Section of Publications and Public Relations
James S. Ayars, B.S.. Technical Editor and Head
Blanche P. V'oung, B.A.. Assistant Technical Editor
Diana R. Braverman, B.A.. Assistant Technical Editor
William E. Clark, Assistant Technical Photographer
Marguerite Verley, Technical Assistant

Technical Library
Ruth R. Warrick, B.S., B.S.L.S., Technical Librarian
Nell Miles, M.S., B.S.L.S., Assistant Technical

Librarian

CONSULTANTS: Herpetolocy, Hobart M. Smith, Ph.D., Professor oj Zoology, University oj Illinois; Parasitology,
Norman D. Levine, Ph.D., Professor of Veterinary Parasitology and of Veterinary Research, University oj Illinois;
WiiDLiFE Research. Wii.lard D. Klimstra. Ph.D.. Assistant Professor of Zoology and Director of Co-operative
Wildlile Research, Southern Illinois University

•Employed on co-<jperatIve projects with one of several agencies: University of Illinois, Illinois Agricultural
Extension Service, Illinois Department of Conservation. United States Army Surgeon General's Office, United State*
Department of Agriculture. United States Fi^h and Wildlife Se:vice, United States Public Health Service, and others.

This paper is a can ribution from the Section of Wildlife Research.

(9S-J85—5M—T'-OB)



CONTENTS

Acknowledgments 289

Study Procedure 290
Foods of Various Species 292

Common Mallard 293

American Pintail 297

Blue-Winged Teal 301

Green-Winged Teal 303

Baldpate 307

Gadwall 308

Shoveler 310

Wood Duck 312

Black Duck 314

Lesser Scaup 315

Ring-Necked Duck 317

Canvasback 320

Redhead 321

Ruddy Duck 322

Common Goldeneye 323

Greater Scaup 323

Oldsquaw 323

Plant Foods 323

Corn 327

Rice Cutgrass 328

Marsh Smartweed 329

Coontail 330

Wild Millet 330

Longleaf Pondweed 331

Red-Rooted Nut-Grass 332

Water-Hemp 332

Nodding Smartweed 333

Buttonbush 334

Large-Seeded Smartweed 334

Nut-Grass 334

Chufa 335

Walter's Millet 335

Sago Pondweed 336

Duck-Potato 336

River-Bulrush 337

Teal Grass 337

Giant Bur-Reed 337

Animal Foods 337

Mollusca 339

Insecta 340

Crustacea 340

Bryozoa 340

Amphibia 340
Arachnida 340
Pisces 340

Grit 340
Lead Shot 342

Summary 343

Literature Cited 344



Aerial view of property belonging to a duck hunting club in the Illinois River valley. The
buildings are surrounded by water, uncultivated bottomland, and cropland. Material for the
duck food study reported here was obtained from this club and many others like it along the
Illinois and Mississippi rivers.



Food Habits of Migratory Ducks in Illinois*

HARRY G. A N D E R S O Nf

TWENTY-FIVE years ago the wa-
terfowl population of North Amer-
ica had dropped to such a low point

that management of this resource became
an important concern of both state and
federal wildlife agencies. As a basis for an

effective, long-time program of manage-
ment for the waterfowl of the Mississippi

Flyway, detailed information about the

diet of ducks that migrate through Illinois

was considered essential.

More than 30 years of drainage, silta-

tion, and pollution had materially reduced

the extent and quality of the Illinois feed-

ing grounds that waterfowl had used for

centuries. Fortunately for some species of

ducks, in the 1930's, mechanical corn pick-

ers came into widespread use in the state.

Mechanical picking left more waste corn

in the fields and made it more easily avail-

able than did picking by hand. Mallards
and black ducks were quick to take advan-

tage of the new food supply.

Previous to 1938, only a small amount
of research had been done on the food

habits of ducks using Illinois as a stopover

on their migration flights. An analysis of

the contents of 185 duck gizzards collected

in Illinois had been made by Martin &
Uhler (1939:5), and a study of the con-

tents of 79 duck gizzards collected from
the Starved Rock Pool near Ottawa and
the Duck Island area near Banner, Illi-

nois, had been made by Bellrose (1938).
The need for more data on the food habits

of waterfowl in Illinois resulted in the in-

vestigation herein reported.

Formally designated as Project 2-R,

"Correlation of Food Supplies With Food
Uses Among Illinois Game Birds," the

investigation was a unit in the program
made possible by the Federal Aid in Wild-
life Restoration Act and was approved in

May, 1939, by the Bureau of Biological

*Federal Aid Project 2-R. Supervision of this project
was assigned by the Illinois Department of Conservation
to the Illinois Xatural History Survey.

tLeader, Federal Aid Project 2-R, June 1, 1939-June
30. 1941 : now employed by the United States Fish and
Wildlife Service.

Survey of the United States Department
of Agriculture (now Fish and Wildlife
Service of the United States Department
of the Interior). The project was offi-

cially begun on June 1, 1939, and ter-

minated on June 30, 1941. Part of the

material and information on which the in-

vestigation was based was collected in

1938. Some of the data derived from the

project have been included in previous pub-
lications (Hawkins, Bellrose, & Anderson
1939; Bellrose & Anderson 1940, 1943;
Bellrose 1941, 1959). Delay in publica-

tion of the final report on the project re-

sulted largely from the author's service in

the armed forces during World War II

and subsequent employment elsewhere.

Supervision of Project 2-R was assigned

to the Illinois Natural History Survey by
the Illinois Department of Conservation.
The project was administered by the late

Dr. Theodore H. Frison, representing the

Natural History Survey, and Anton J.

Tomasek, representing the Department of

Conservation. Dr. Lee E. Yeager, Arthur
S. Hawkins, and Frank C. Bellrose pro-

vided technical supervision ; all three were
members of the Natural History Survey
staff at the time of the investigation.

ACKNOWLEDGMENTS

The writer of this paper gratefully ac-

knowledges the assistance of many per-

sons. He extends his thanks to personnel

of the United States Bureau of Biological

Survey, later the Fish and Wildlife

Service, for permitting use of the Patuxent
Research Laboratory and for giving in-

struction in food habits studies during the

early stages of this project, especially Dr.

Alec Martin for his many helpful sugges-

tions and his encouragement. He expresses

his appreciation to many present and for-

mer members of the staff of the Illinois

Natural History Survey, especially Dr.

Herbert H. Ross, Dr. Carl O. Mohr, and
Dr. B. D. Burks for their aid in identify-

ing insects; the late Dr. Leo R. Tehon for

[289]



290 Illinois Natural History Survey Bulletin V^ol. 27, Art. 4

his aid in idcntifyinti seeds; William Mar-
qiiardt, Robert Welk, and W^illiam Rob-

ertson for their statistical assistance; Dr.

Harlow B. Mills and Dr. Thomas G.

Scott for their man\ helpful suggestions;

and Frank C. Bellrose and James S. Avars

for their assistance in the writing and edit-

ing of this report.

Finally, the author extends his thanks

to a great many individual hunters and

duck clubs for whole-hearted co-operation

in the Held investigations and in the pres-

ervation of material.

STUDY PROCEDURE

Two general steps were involved in the

study procedure: (1) the collection of

duck gizzards from strategic locations

along the Illinois River and the Missis-

sippi River and (2) the laboratory an-

alysis of collected material.

The limited duration of this investiga-

tion made it desirable to choose collection

sites that would yield a large quantity of

gizzards within the short time of three

hunting seasons and that would provide

representative samples of the important

duck species using the major river valleys

in Illinois, frontispiece. Twenty-one sites

were selected along the Illinois River be-

tween Ottawa and Florence, Illinois, and
1 1 sites were selected along the Mississippi

River between Rock Island and Quincy,

Illinois, fig. 1. Gizzards were obtained

during the hunting seasons of 1938, 1939,

and 1940 by Arthur S. Hawkins and
Frank L'. Bellrose of the Illinois Natural
History Survey and the author.

Arrangements were made for collecting

the gizzards of ducks taken by members of

duck hunting clubs, by individual hunters,

and others. At most hunting clubs, mem-
bers had their ducks dressed as they

brought the birds in from marshes or lakes,

fig. 2; the clubs were a source of large

numbers of gizzards. Individual or free-

lance hunters often hired local profes-

sional duck pickers to clean their kills;

these pickers were another source of giz-

zards.

Co-operators were supplied with jars

partially filled with a 10 per cent formal-
dehyde solution ; each jar bore a printed
label denoting a species of duck. Duck
pickers were instructed to drop each giz-

zard into an appropriate jar. Gizzards
were collected from the co-operators once

each week and stored until such time as

their contents could be analyzed.

During the three fall hunting periods

of 1938-1940, 4,977 gizzards were col-

lected, table 1 ; 90.52 per cent (4,505) of

the gizzards came from locations along the

Illinois River and 9.48 per cent (472)

Fig. 1.—Map showing the areas from which
duck gizzards were collected in the autumns
of 1938, 1939, and 1940 between Ottawa and
Florence on the Illinois River and between
Rock Island and Quincy on the Mississippi

River.

came from collecting sites along the Mis-
sissippi River. The sample from the Illi-

nois River valley represented 1.6 per cent

of the 1938 kill estimated for that region,

2.2 per cent of the 1939 kill, and 0.5 per

cent of the 1940 kill. A breakdown of the

number of gizzards obtained from 17 spe-

cies of ducks is given in table 1 by year

and river system. The species are listed



August, 1959 Anderson: Food Habits of Migratory Ducks 291

Fig. 2.—Picking ducks at a hunting club in the Illinois River valley. Duck gizzards culifM ted

from this and similar clubs provided most of the material on which the present study is based.
As ducks were dressed, each gizzard was placed in a jar containing a formaldehyde solution
and bearing a printed label that denoted the duck species represented. Nearly 5,000 gizzards
representing 17 species of ducks were collected.

Table 1.—Number of waterfowl gizzards collected in Illinois, 1938—1940, at stations along
the Illinois and Mississippi rivers.



292 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

in descending order of the estimated num-
bers of individuals in the fall flight.

The procedure in making analyses of

the gizzard contents was in accordance

with standard practices followed by the

United States Bureau of Biological Sur-

vey (now United States Fish and Wild-
life Service) for food habits studies (Cot-

tam 1936:9-10). The contents were sep-

arated first into organic and inorganic sub-

stances and the volume of each expressed

as a percentage of the total volume. The
organic foods were then separated into

plant and animal foods and the volume of

each group expressed as a percentage of

the total organic volume. As an example,

the contents of a mallard gizzard were 8

cc. (80 per cent) organic material and 2

cc. (20 per cent) inorganic material. Of
the total organic foods, 6 cc. (75 per cent)

consisted of plant foods and 2 cc. (25 per

cent) of animal foods.

Inorganic material was found in the

gizzards in small to large amounts and

consisted primarily of sand, gravel, and
calcareous shell material. Individual par-

ticles were classified as to size in milli-

meters as well as to type and volume.
An effort was made to identify each

item in the organic contents, even though
it constituted only a trace or a fraction of

1 per cent of the volume, tables 38 and 39.

The technical names of most identifiable

plant items listed in table 38 were taken

from Gray's Manual of Botany (Fernald

1950). The technical names of animal
items listed in table 39 were taken from
several authorities and depended upon the

groups of animals involved. Seeds of some
of the duck food plants discussed in this

report are shown in fig. 3.

FOODS OF VARIOUS SPECIES

Data obtained from this study provided

important facts about food preferences of

each of the species of ducks represented.

The proportions of plant and animal foods

Fig. 3.—Seeds included in the autumn diet of ducks migrating through Illinois: (top row,
left to right) giant bur-reed, pickerelweed, American lotus, buttonbush, longleaf pondweed

;

(second row, left to right) nodding smartweed, large-seeded smartweed, swamp smartweed,
marsh smartweed, chufa; (third row, left to right) Walter's millet, Japanese millet, wild
millet, rice cutgrass, water-hemp; (bottom row, left to right) duck-potato, lophotocarpus, Ameri-
can bulrush, soft-stem bulrush, sago pondweed.



August, 1959 Anderson : Food Habits of Migratory Ducks 293

in the gizzards of the most important spe-

cies are shown in fig. 4.

Common Mallard
A nas platyrhynchos

Because hunters co-operating in this

study seldom distinguished between the

common mallard, Anas platyrhynchos, and

the black mallard or black duck, A. rub-

ripes, undoubtedly a few of the 2,825 giz-

zards labeled as those of common mal-

lards, table 2, were from black ducks.

A mallard gizzard was assumed to be

full if its gross contents amounted to 16 cc.

or more. The contents of individual giz-

zards ranged from 0.5 to 24.0 cc. and av-

eraged 8.28 cc. per gizzard. Fewer than

250 of the mallard gizzards were less than

one-quarter full or more than three-quar-

ters full. Most of the gizzards with small

amounts of food were collected early in

the season, while most of those nearly full

were collected between November 20 and
December 5, a time when corn was avail-

able in large quantities.

The gross contents of the 2,825 mallard

gizzards amounted to 22,379.73 cc, of

which 37.25 per cent (8,335.46 cc.) was



294 Illinois Natural History Survey liuLLETiN Vol. 27, Art. 4

Table 2.—Mallard gizzards collected in Illinois in approximately 2-week periods, 1938—1940.



August, 1959 Anderson: Food Habits of Migratory Ducks 295

grit and 62.75 per cent (14,044.27 cc.)

was organic in substance, tables 3 and 4.

In 80 per cent of the mallard gizzards, the

organic matter consisted of plant parts ex-

clusively.

Plant Foods (97.73 Per Cent of Or-
ganic Contents).—Plant parts, which
formed nearly 98 per cent of the food in

the mallard gizzards, appeared in all but

some gizzards, leaves and stems of coon-

tail, and rootstocks or tubers of rice cut-

grass, chufa, and duck-potato constituted

the entire plant contents.

Listed in table 3 are the most important

plant foods found in the mallard gizzards

collected for this study. Corn made up al-

most half of the total volume of plant

foods ; the amount of corn in the gizzards

100

OCT. 16-31 NOV. 1-15 NOV. 16-30 DEC. 1-15

Fig. 5.—Principal plant foods consumed by mallards in Illinois from mid-October to mid-
December, 1938-1940, as determined by volumetric analyses of gizzard contents. The curves

represent the averages for the periods indicated.

13 of the gizzards. The plant contents of

individual mallard gizzards ranged from a

trace to 20 cc. and averaged 4.86 cc. per

gizzard. The proportion of the organic

contents made up of plant structures

ranged from 95.17 per cent in 1938 to

99.28 per cent in 1940. Field observations

in the areas from which the gizzards w^ere

collected in the 3-year period showed that

water levels fluctuated from year to year,

thus allowing native food plants to be

more easily accessible in some years than

in others.

Although there was some plant debris

that could not be identified (0.02 per

cent), 101 species of plants in the mallard

gizzards were identified. Most of the ma-
terial was in the form of seeds, but, in

was proportionally greater late in the sea-

son than early, fig. 5. Rice cutgrass, coon-

tail, wild millet or barnyard grass, and
marsh smartweed comprised more than
half of the volume of native wild foods.

The volume of emergent and moist-soil

plant parts was four times as great as the

volume of submergent vegetation.

Plant species that individually made up
less than 1.0 per cent of the total organic

volume had been ingested either in small

units by a large number of mallards or in

large volumes by a few birds. Some of the

plant particles may have been taken inci-

dentally along with more desirable foods.

Animal Foods (2.27 Per Cent of Or-
ganic Contents).—Animal matter was
found in mallard gizzards taken in each



296 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

jable 4.—The most important animal foods identified in 2,825 mallard gizzards collected

in Illinois, 1938-1940.

Animal

TOTAL AMSLiL

BRYOZOA staroblasts

MOLLUSCA
Gastropoda, snails

Stagntiola

Planorbis

Hiftisorna trivohis

Carinijex rtewberryi

Physa
Campeloma
Amnicola
Flunwicola
Pletirocera

L'nidenritied Gastropoda
Pelecvpoda, mussels

Sphaeriidae

Pisidium
Musculium transversum

Sphaerium
Unidentified Sphaeriidae

Unionidae, fresh-water clams
Unidentified Pelecypoda

Unidentified Mollusca
ARTHROPODA
Crustacea

Ostracoda
Malacostraca

Decapoda, Cambarus virilis, crayfish

Amphipoda, Gammarus
Isopoda, Asellus

Insecta
Neuroptera, Corydalis cornuta, hellgrammites

Ephemeroptera, Hexagenia nymphs, mayflies

Odonata
Anisoptera, dragonflies

Aeshna
Gomphus notatus

Unidentified Anisoptera
Zygoptera, Coenagrionidae nymphs, damsel

Hies

Unidentified odonata nymphs
Homoptera, Cicadellidae, leafhoppers

Hemiptera
Corixidae, Corsxa, water boatmen
Notonectidae, Nolonecta, backswimmers. . .

Nepidae, Ranatra, waterscorpions

Belastomatidae, water bugs. . .

Gerridae nymphs, water striders

Lygaeidae, Lygaeus, chinch bugs
Pentatomidae, stink bugs
Unidentified Hemiptera

Coleoptera

Carabidae, ground beetles

Halipidae
Dy tiscidae, diving beetles

Gyrinidae, whirligig beetles

Hydrophilidae, water scavenger beetles. . .

.

Staphylinidae, rove beetles

Buprestidae, flatheaded wood borers

Occurrence
(Number of
Gizzards)

20

2

1

4
11

4
1

6

45

1

7

11

1

5

11

16

10

2

6

1

49

2
1

1

7

4
2

169

2

1

17

1

1

3

1

28
2

121

4
6

3

1

Volume
(Cubic

Centimeters)

Per Cent of
Total Organic

Contents

318 74

30

0,60
1.50
0.47
0.40

20
60
30
80
20

22.40

1.30
9.20

20.90
2.70
3.40
10.70
8.20

20.40
0.07
0.58

0.50
15.12

0.30
0.40
0.20'

8.00
1.40
0.20

75.79
0.30
0.60
15.20

t

t

0.40
0.40

0.61
0.07
13.39
0.42
6.60
0.04
t



August, 1959 Anderson: Food Habits of Migratory Ducks 297

Table 4.—Continued.

Animal

Elmidae
Scarabaeidae, ^://'^o^/ //J a'/-f//«r//<j, scarab beetles

Chrysomelidae, leaf beetles

Curculionidae, snout beetles

Unidentified Coleoptera
Irichoptera, caddisflies

Hydroptilidae.

Hydropsychidae, Hydropsyche larvae

Unidentified Trichoptera cases

Lepidoptera
Noctuidae, cutworm moths
Unidentified Lepidoptera moths

Diptera
Chironomid larvae, midges
Tabanidae, horse flies

Unidentified Diptera
Hymenoptera

Formicidae, ants

Tiphiidae, Tiphia, tiphiid wasps
Unidentified Insecta

Arachnida
AcARiNA, water mites

CHORDATA
Pisces, fish

Amphibia, frogs

NONFOOD
Parasitic Worms
Feathers

UNIDENTIFIED

Occurrence
(Number of
Gizzards)

4

15

4

28
5

7

2

1

72

]

11

4
1

10

13

19

14

1

1

43
3

Volume
(Cubic

Centimeters 1

t

0.06
0.26
2 80

SO

0.77
8.20
3.16

29
10

27.20
0.20
1.13

3.77
62

t

0.22
1 00

0.20
4.90
0.20

Per Cent of
Total Organic

Contents

0.0004
0.002
0.02
0.004

0.005
0.06
0.02

0.002
0.0007

0.19
001

008

0.03
0.004

0.002
0.007

0.001

0.03
0.001

of the collecting periods of the fall months,
the greatest volume from November 16 to

freeze-up. Even though animal foods were
found in 580 mallard gizzards, the}^ ap-

peared to be relatively unimportant in the

fall diet. The animal remains in individ-

ual gizzards amounted to only a trace, ex-

cept in a few gizzards which held as much
as 12 cc. each.

An animal group was considered an im-

portant source of mallard food if it pro-

vided at least 0.1 per cent of the total or-

ganic contents. Of the animal foods found
in the mallard gizzards, table 4, about
two-thirds of the volume consisted of in-

sects and approximately one-third of snails

and mussels.

Inorganic Contents (37.25 Per Cent
of Total Contents).—Grit and other in-

organic material in individual mallard
gizzards varied from a trace to 9.4 cc. and
averaged 2.95 cc. per gizzard. Except for

calcareous material in one gizzard, the in-

organic contents consisted of stones rang-
ing in size from minute to 19 mm. (largest

dimension) ; however, in most instances,

the stones did not exceed 4 mm.

American Pintail

Ajias acuta

In about 80 per cent of the pintail giz-

zards collected, table 5, the organic con-
tents consisted of plant material exclu-
sively. Vegetation was found in 99 per
cent of the gizzards. These percentages
seem to indicate that the pintail, in Illi-

nois at least, utilizes vegetation to a slight-

ly greater degree than does the mallard.
Of the pintail gizzards collected, 31 came
from the Mississippi River area and 850
from the Illinois River valley.

A pintail gizzard was assumed to be full

if the gross contents amounted to 14.0 cc,

or more ; the average was 6.2 cc, and the

extremes ranged from a trace to 16.5 cc.

Approximately 210 gizzards were either

less than one-quarter or more than three-

quarters full, and only 6 were classified as

full. In no collecting period were the pro-

portions of full and nearly full gizzards



298 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

sijj;niiicantl_\' jjreater than in any other. The jjross contents of 881 pintail giz-

Fatt\ tissue was much in evidence around zards amounted to 5,431.91 cc, of which

most of the pintail gizzards. 37.52 per cent (2,038.20 cc.) was grit and

Table 5.—Pintail gizzards collected in Illinois in approximately 2-week periods, 1938-1940.



August, 1959 Anderson: Food Habits of Migratory Ducks 299

Table 7.—The most important animal foods identified in 881 American pintail gizzards
collected in Illinois, 1938-1940.

Animal

TOTAL ANIMAL.

BRYOZOA statoblasts

MOLLUSCA
Gastropoda, snails

Planorbis

Helisoma trivolvis

Gyraiiliis parvus
Physa gyrina
Campeloma
Lioplax stibglobosHS

Amnicola
Unidentified Gastropoda

Pelecvpoda, mussels

Sphaeriidae
Pisidium
Musculium transversiim

Sphaerium
Unionidae, fresh-water clams
Unidentified Pelecypoda

Unidentified Mollusca
ARTHROPODA
Crustacea
Ostracoda
Malacostraca
Amphipoda, Gauimarus
Isopoda, Asellus

Insecta
Orthoptera, grasshoppers

Neoconocephalus
Ephemeroptera, mayflies

Hexagenia nymphs
Caenis nymphs

Odonata
Anisoptera, dragonflies

Anax Junius
Anisoptera nymphs

Zygoptera, damsel nies

Coenagrionidae
Zygoptera nymphs

Unidentified Odonata
Hemiprera

Corixidae, Cor/.vrt, water boatmen
Nepidae, Ranatra, waterscorpions
Pelastomatidae, predaceous water bugs. . . .

Miridae, Lygus lineolaris

Lygaeidae, Lygaeus kalmii, chinch bugs. . . .

Unidentified Hemiptera
Coleoptera

Carabidae, ground beetles

Casnonia pennsylvanica

Unidentified Carabidae
Haliplidae

Dytiscidae, diving beetles

Colymbetes

Unidentified Dytiscidae
Hydrophilidae larvae, water scavenger beetles

Staphylinidae, rove beetles

Scarabaeidae, Aphodins distinctus, scarab

beetles

Occurrence
(Number of
Gizzards)

15

2

1

1

1

4
I

1

22

4
2
7

1

8

12

3

1

1

2

2

27
1

5

1

1

1

1

9

1

1

41

2

1

Volume
(Cubic

Centimeters)

102.27

1.44

t

0.70
0.10
0.10
3.70
0.30
0.40
15.54

5.08
2.70
6.70
1.70
4.30
6.07

0.50

t

0.11

20

4.50
0.10

2.90
0.10

0.10
0.90

90

6.73
0.20
2.53
0.02
0.03
t

0.04
t

0.10

0.20
7.30
0.20
0.20

0.05

Per Cent of
Total Organic

Contents

3.01

0.04

0.02
0.003
0.003
0.11
0.009
0.01

0.46

0.15
0.08
0.20
0.05
0.13
0.18

0.01

0.003

0.006

0.13
0.003

0.09
0.003

003
0.03
0.03

0.20
0.006
0.07

. 0006
0009

0.001

0'003

0.006
0.22
0.006
0.006

0.001



300 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

Table 7.

—

Continued.

.Animal
Occurrence
(Number of
Gizzards)

Volume
(Cubic

Centimeters.)

Per Cent of
Total Organic
Contents

Chrysomelidae, leaf beetles

Diabrotica iindeciwpunctata hownrdi
Lixiis

Unidentified Chrysomelidae
Curculionidae, snout beetles

Trichoptera

Hydroptiiidae cases, caddisflies

Hydropsychidae, Hydropsyche
Unidentified Trichoptera

Diptera
Chironomidae larvae, midges
Unidentified Diptera

Hymenoptera
Ichneumonidae, ichneumon flies

Tiphiidae, Tiphia

Formicidae, ants

Unidentified Hymenoptera
Unidentified Insecta

Arachnida
Araneae, spiders

Argiopoidea
Unidentified Araneae

Unidentified Arachnida
Acarina, Hydracarina, water mites

CHORDATA'
Pisces, fish

NONFOOD, feathers

UNIDENTIFIED

1

1

1

2

33
1

5

39
2

1

1

2

1

1

2

15

1

t

0.20
t

t

3.42
0.30
0.25

18.09
0.03

t

0.10
0.10
0.96
t

0.03
t

t

0.22

t

1.23
0.60

0.006

0.10
009
007

0.53
0.0009

0.003
0.003
0.03



August, 1959 Anderson: Food Habits of Migratory Ducks 301

moist-soil plants were decidedly less abun-

dant, than in the Illinois River valley.

Animal Foods (3.01 Per Cent of Or-
ganic Contents).—Animal matter was
found in a few pintail gizzards taken in

each collecting period; it was most abun-

dant during the period October 16-31.

This type of food was found in 202 of the

pintail gizzards, but only 8 contained ani-

mal matter exclusively.

Most pintail gizzards contained only

traces of animal matter ; however, one

gizzard contained 1 1.5 cc. of midge larvae.

a larger percentage of animal matter than

did those of the mallard or the pintail.

Plant structures occurred in 53 per cent of

the blue-winged teal gizzards analyzed.

Most blue-winged teals leave Illinois be-

fore the middle of November, and only

one gizzard representing the blue-wings

was collected after that time, table 8.

Only eight gizzards of the blue-winged

teal were collected from the Mississippi

River region.

A blue-winged teal gizzard was consid-

ered full if the gross contents amounted to

Table 8.

1938-1940.

-Blue-winged teal gizzards collected in Illinois in approximately 2-week periods,



302 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

A plant making up at least 1.0 per cent

of the organic material was consiaered an

important blue-winged teal food, table 9.

Thirteen species and one genus, aggregat-

ing 7b.6b per cent of the organic contents,

were in this category: three nut-grasses,

two millets, coontail, water-hemp, marsh

diet than that of the mallard or the pintail.

In the majority of blue-winged teal giz-

zards containing animal parts, the animal

contents ranged in volume from 0.1 to 1.0

cc. ; some gizzards contained only a trace

of animal matter and others as much as

2 cc. each. The animal groups considered

Table 9.—The most important plant foods identified in 129 blue-winged teal gizzards col-

lected in Illinois, 1938-1940.

Plant

TOTAL PLANT.

Cvperus
erythrorhizos, red-rooted nut-grass

slrigosus, nut-grass

escnlentus, chufa

Unidentified

Echinochloa
criisgalli, wild millet

waiteri, Walter's millet

Ceratophyllum
demetsttm, coontail

Unidentified

Acnida altissima, water-hemp
Polygonum

coccineum, marsh smartweed
lapathi/oliiim, nodding smartweed
pensylvanicum, large-seeded smartweed.
punctatum, dotted smartweed
Other Polygonum

Eragrostis hypnoides, teal grass

Cephalanthus occidentalis, buttonbush. . .

.

Panictim dichotomiflorum, fall panic-grass.

Lemna minor, lesser duckweed
Leersia oryzoides, rice cutgrass

Potamogeton
epihydrus, ribbon-leaf pondweed
nodosus, longleat pondweed
pectinatus, sago pondweed
Other Potamogeton

Other plants

Occurrence
(Number of
Gizzards)

81

18

1

15

5

9

4
47

43
45

12

9

10

12

15

4
6

10

1

10

5

4
96

Volume
(Cubic

Centimeters)

Per Cent of
Total Organic

Contents

132.82 83.63

66.00



August, 1959 Anderson: Food Habits of Migratory Ducks 303

Table 10.—The most important animal foods identified in 129 blue-winged teal gizzards
collected in Illinois, 1938-1940.

Animal

TOTAL ANIMAL

BRYOZOA statoblasts

MOLLUSCA
Gastropoda, snails

Gyraulus parvus
Unidentified Gastropoda

Pelecypoda, mussels
Pisidinm
Sphaerium

Unidentified Mollusca
ARTHROPODA
Crustacea
Copepoda
Ostracoda

Insecta
Ephemeroptera, Hcxagenia, mayflies

Hemiptera, Corixa, water boatmen . .

Coleoptera

Carabidae, ground beetles

Dytiscidae, diving beetles

Gyrinidae, whirligig beetles

Curculionidae, snout beetles

I richoptera

Hydroptilidae cases, caddisfiies. . .

.

Unidentified Trichoptera cases. . . .

Diptera, Chironomidae, midges
Unidentified Insecta

Arachnida
AcARiNA, Hydracarina, water mites... .

NONFOOD, feathers

Occurrence
(Number of



304 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

This fact probably reflected differences in tures representing 63 species of emergent,

plant food availability. moist-soil, submergent, and terrestrial

In the gizzards of the green-wings, plants were identified. Seeds and seed-

there was some plant debris (0.09 per coat fragments comprised the bulk of the

cent) that could not be identified; struc- plant structures, although coontail stems

Table II.—Green-winged teal gizzards collected in Illinois in approximately 2-week periods,

I938-I940.



August, 1959 Anderson: ]<'ood Habits of Migratory Ducks 305

and leaves and duckweed particles were of the gizzards of green-wings and in the

numerous. aggregate amounted to more than 75 per
Plant foods that contributed at least 1.0 cent of the organic contents were three

per cent each to the total organic contents nut-grasses, two millets, teal grass, marsh

Table 13.—The most important animal foods identified in 393 green-winged teal gizzards
collected in Illinois, 1938-1940.

Animal
Occurrence
(Number of
Gizzards)

Volume
(Cubic

Centimeters)

Per Cent of
Total Organic

Contents

TOT.-IL ANIMAL

BRYOZOA statoblasts

MOLLUSCA
Gastropoda, snails

Gyraulus parvus
Physa gyrina
Unidentified Gastropoda

Pelecypoda, Sphaerium, seed shells

Unidentified Mollusca
ARTHROPODA
Crustacea

Branchiopoda
Fairy shrimps
Unidentified Branchiopoda

Copepoda
Cyclops

Canthocampus
Unidentified Copepoda

Ostracoda
Candona
Cypris
Unidentified Ostracoda

Malacostraca
Amphipoda, Gammarus
Isopoda, Aselliis

Insecta
Orthoptera, Tettigoniidae, grasshoppers . . . .

Ephemeroptera, mayflies

Hexagenia nymphs
Caenis nymphs

Odonata
Anisoptera, Aeshna, dragonflies

Zygoptera, Coenagrionidae, damselflies. . .

.

Odonata nymphs
Hemiptera, Corixa, water boatmen
Coleoptera

Carabidae, ground beetles

Dydscidae, diving beetles

Gyrinidae, whirligig beetles

Staphylinidae, rove beetles

Elmidae
Chrysomelidae, Diahrotica undecimpunctata

howardi, leaf beetles

Unidentified Coleoptera
Trichoptera

Hydroptilidae cases, caddisflies

Unidentified Trichoptera
Diptera, Chironomidae larvae, midges
Hymenoptera

Ichneumonidae, ichneumon flies

Formicidae, ants

Unidentified Insecta

Arachnida
AcARiNA, Hydracarina, water mites

NONFOOD, feathers

69

1

1

26
1

15

1

2

.3

2

1

2

1

57

3

2

2

1

3

4

3

58

33
2

1

1

43
3

66

1

1

2

T

20
12

67.94

5.33

0.08
1.70
8.26
0.10
4.56

1.30
0.10

1.40
t

1.20

0.02
0,01
1.43

t

0.10

0.30

0.30
t

0.30
3.60
1.50

15.34

0.11

0.67
t

t

t

t

0.05

1.24
0.20
17.24

0.05
t

0.12
t

0.04
1.29

15 04

1.18

0.02
0.38
1.83
0.02
1.01

0.29
0.02

0.31

0.27

0.004
0.002
0.32

0.02

0.07

0.07

0.07
0.80
0.33
3.39

0.02
0.15

0.01

0.27
0.04
3.82

01

0.03

0.009
0.29



306 Illinois Natural History Survey Bulletin Vol. 27, Art 4

sinartweed, nodding sniartvveed, lesser

duckweed, coontail, rice cutgrass, water-

hemp, the pondweeds as a group, corn, but-

tonbush, and duck-potato, table 12. Most
of these plants grow on mud Hats or moist

iand bars.

Animal Foods (15.04 Per Cent of

Organic Contents).—Animal matter ap-

peared in more than half of the gizzards

of the green-winged teals and in a few giz-

zards in greater volume than the plant

foods. It was found in gizzards collected

in all four periods but in the greatest per-

centage in those collected from October

16 through November 15.

Individual gizzards of the green-winged

teals contained a trace to 3.1 cc. of animal

parts and averaged 0.31 cc. More than a

third of them contained 0.1 to 1.0 cc. of

animal matter each. An animal group rep-

resenting at least 0.1 per cent of the total

organic contents of the gizzards of these

teals was considered important, table 13.

Insects comprised a little less than two-

thirds of the volume of animal matter in

gizzards of the green-wings. In greatest

volumes were midge larvae, water boat-

men, and Odonata nymphs. The MoUusca
group, represented principally by snails,

made up 21.54 per cent of the animal con-

tents. Other important animal foods

were Bryozoa statoblasts and crustaceans.

Inorganic Contents (41.94 Per Cent
of Total Contents).— In most of the

green-winged teal gizzards collected, al-

most one-half of the gross contents con-

sisted of inorganic material. The volume
of inorganic matter in individual gizzards

Table 14.

—

Baldpate gizzards collected in Illinois in approximately 2-week periods, 1938-1940.



August, 1959 Anderson: Food Habits of Migratory Ducks 307

ranged from a trace to 1.9 cc. and aver-

aged 0.8 cc. Gravel particles varied in size

from minute to 9 mm. (largest dimen-

sion), but seldom exceeded 3 mm. Very
little other inorganic material was present

in gizzards containing grit particles 7, 8,

or 9 mm. in size.

Baldpate
Alareca am ericona

Analyses of the contents of gizzards col-

lected for this study indicated that in Illi-

nois the baldpate, or widgeon, during the

fall months is primarily a vegetarian ; it

appears to ingest animal foods only inci-

dentally with plant parts. Because the

baldpate reaches its peak population in this

state early in the fall, most of the gizzards

representing this species were obtained

during the first two collecting periods,

table 14. Of the 160 samples, only 8 were

collected from stations along the Missis-

sippi River.

A baldpate gizzard, about as large as

that of a mallard or pintail, was consid-

ered to have a capacity of 13 cc. Gross
contents of individual gizzards ranged

from 1.4 to 11.0 cc. and averaged 4.99 cc.

Nearly one-fifth of the gizzards were less

than one-quarter full and none was full.

Even on gizzards in which the contents

averaged less than half the gizzard ca-

pacity, fatty tissue was prevalent.

The gross material in the 160 gizzards

of baldpates totaled 799.82 cc. Of this

amount, 57.45 per cent (459.50 cc.) con-

sisted of grit and the remaining 42.55 per

cent (340.32 cc. ) consisted of plant and

animal parts.

Plant Foods (93.66 Per Cent of Or-
ganic Contents).—In 1938, plant struc-

tures made up 91 per cent of the organic

Table 16.—The most important animal foods identified in 160 baldpate gizzards collected

in Illinois, 1938-1940.

Animal

TOTAL ANIMAL.

BRYOZOA statoblasts

MOLLUSCA
Gastropoda, snails

Gyraulus parvus
Physa
Unidentified Gastropoda

Unidentified Mollusca .-hells

ARTHROPOD

A

Crustacea, Aselltis

Insecta
Ephemeroptera, Hexagenia nymphs, mayflies

,

Odonata nymphs, dragon flies

Homoptera, Cicadellidae, leafhoppers

Draeculacephala
Unidentified Homoptera

Hemiptera
Corixa, water boatmen
Lygus lineolaris

Coleoptera
Carabidae, Omophron
Dytiscidae, diving beetles

Scarabaeidae, Geotriipes, scarab beetles. . .

.

Chrysomelidae, Diabrotica, leaf beetles ....

Trichoptera
Hydroptilidae cases, caddisflies

Unidentified Trichoptera cases

Diptera
Chironomidae larvae, midges
Unidentified Diptera larvae

Arachnida
Acarina, Hydracarina, water mites

NONFOOD, feathers

Occurrence
(Number of
Gizzards)

Volume
(Cubic

Centimeters)

n.57

0.20

0.30
0.20
2.10
0.10

0.05

0.10
1.20

t

t

14.00
t

0.20
1.90
0.20
t

0.02
0.10

0.90
t

t

t

t

Per Cent of
Total Organic

Contents

6.34

0.06

0.09
0.06
0.62
0.03

0.015

0.03
0.35

4.11

0.06
0.56
0.06

0.006
0.03

0.26



308 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

contents of the baldpate gizzards; in 1939

and 194U they represented 100 per cent of

the organic material. Volumes in individ-

ual gizzards varied considerably; in a

number of gizzards only a trace of plant

material was found, while in others the

plant contents ranged up to 6.5 cc. Ihe
average was 1.99 cc, a rather low volume

for the size of the gizzard.

Plant debris amounting to 0.33 per cent

of the organic contents of the baldpate giz-

zards could not be keyed to species because

of its finely ground condition ; however, 34

species of plants were identified. The bulk

of this plant material consisted of stems

and leaves of coontail. The remaining

plant material, except for algae and duck-

weed, consisted of seeds and seed coats.

Of 1 1 plants important to the baldpate

(plants constituting at least 1.0 per cent of

the total organic contents of the baldpate

gizzards collected), coontail appeared to

be the most important, table 15. Nearly

three-fourths of the organic volume con-

sisted of this plant. Field observations

showed that baldpate concentrations were

usually found in lakes or sloughs where
coontail beds flourished. Corn was found

in only four baldpate gizzards, and this

was probably bait. Moist-soil plants in

some gizzards indicated the birds had fed

on flooded mud flats.

Plant species of lesser importance, those

that contributed less than 1.0 per cent of

the organic contents of the baldpate giz-

zards, were taken by only a few baldpates

but in fairly large amounts. Most of these

were moist-soil plants important to the

teals and the pintail.

Animal Foods (6.34 Per Cent of Or-
ganic Contents).—Most of the animal

foods found in the baldpate gizzards, table

16, were species associated with submerged
plant beds and had been ingested probably

while the birds were browsing on coontail.

Volumes in individual gizzards ranged
from a trace to 6.8 cc, most of them less

than 0.5 cc.

Aquatic insects, most of them water
boatmen, comprised more than four-fifths

of the animal material found in the bald-

pate gizzards. The Mollusca group was
represented only by univalves. Hryozoans,

water mites, crustaceans, and feathers

were present in very small amounts.
Inorganic Contents (57.45 Per Cent

of Total Contents).—The inorganic ma-
terial in individual baldpate gizzards var-

ied in volume from 0.5 to 5.1 cc. and av-

eraged 2.87 cc. Most of the grit consisted

of fine, white sand crystals. In four-fifths

of the gizzards, stones were less than 2

mm. in size (largest dimension). In the

remaining 20 per cent, there were, in ad-

dition to the fine sand, a few stones rang-

ing from 3 to 10 mm. in size.

Gadwall
Anas strepera

This study indicated that the gadwall,

like the baldpate, is primarily a vegetarian

in the fall months in Illinois. Four-fifths

of the gadwall gizzards collected for this

study contained no animal material. Ma-
terial was collected for the Hrst three of

the four collecting periods in the years of

this study, table 17. Of the 98 gizzards

obtained, only 7 were from the Mississippi

River.

A gadwall gizzard was considered to

have a capacity of 14 cc. None was filled

to capacity; the contents of individual giz-

zards ranged in volume from 1.0 to 10.5

cc. and averaged 5.2 cc. One gizzard was
completely empty; its condition indicated

the bird was emaciated and probably sick.

About one-tenth of the gizzards were less

than one-quarter full ; in these the con-

Table 17.—Gadwall gizzards collected in Illinois in approximately 2-week periods, 1938—1940.



August, 1959 Anderson: Food Habits of Migratory Ducks 309

tents were mostly grit. No gizzard was
more than three-quarters full; yet most

birds were apparently healthy when shot,

since fatty tissue was evident.

The total contents of the gadwall giz-

zards amounted to 509.29 cc, of which
74.04 per cent (377.10 cc.) was grit and

25.96 per cent (132.19 cc.) was organic

material. Vegetable foods comprised 97.21

per cent and animal foods 2.79 per cent of

the organic contents, tables 18 and 19.

Plant Foods (97.21 Per Cent of Or-
ganic Contents) .—Plant items were found

in 89 of the 98 gadwall gizzards ; only

gritty material was found in the remain-

ing 9. The plant food contents of indi-

Table 18.—The most important plant foods identified in 98 gadwall gizzards collected in

Illinois, 1938-1940.

Plant
Occurrence
(Number of
Gizzards)

Volume
(Cubic

Centimeters)

Per Cent of
Total Organic

Contents

TOT^L PLANT.

Ceratophyllum demersum^ coontail

Algae
Polygonum

coccineum, marsh smartweed
lapathifolium, nodding smartweed
pensylvanicum, large-seeded smartweed.
Other Polygonum

Echinochloa crusgalli, wild millet

Digitaria

sanguinalis, crab-grass

ischaemum, smooth crab-grass

Leersia oryzoides, rice cutgrass

Scirpus
acutus, hard-stem bulrush

fluviatilis, river-bulrush

validus, soft-stem bulrush

Potamogeton nodosus, longleaf pondweed..
Heteranthera diibia, mud-plantain
Other plants

48
13

18

10

5

3

10

1

1

2

2

2

6

1

47

128.50 97.21

94,98



310 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

vidual j:;izzards varied from a trace to 6

cc. and averaged 1.3 cc.

Thirty-four species of plants from the

gadwall gizzards were identified; 0.88 per

cent of the plant material was too finely

ground to be recognized. The major por-

tion of the plant material consisted of tlic

stems and leaves of coontail and the en-

tire plants and particles of duckweed and

algae.

Plant groups contributing at least 1.0

per cent each to the organic contents of the

tals, each under 1 mm. in size. Occasion-

ally, a stone up to 5 mm. (largest dimen-

sion) was found.

Shoveler
Spatula clypeata

Analyses of the contents of the duck giz-

zards collected in 1938, 1939, and 1940

indicated that, although animal foods are

more readily consumed by the shoveler

than by any other species of the dabbler

group, this duck is still very much a vege-

Table 20.—Shoveler gizzards collected in Illinois in approximately 2-week periods, 1938-1940.



August, 1959 Anderson: Food Habits of Migratory Ducks 311

the shoveler gizzards collected, tables 21

and 22.

Plant Foods (82.36 Per Cent of Or-
ganic Contents).—The shoveler, more
than any other species of duck, skims food

from the surfaces of lake and marsh bot-

toms in very shallow^ water, much of it

less than an inch in depth. Because of this

Nine plants, each represented by at least

1.0 per cent of the organic contents, pro-

vided the bulk of the fcod in the shoveler

gizzards, table 21. Plants making up less

than 1.0 per cent each of the total organic

contents were not considered important
even though they appeared in large vol-

umes in a few gizzards. Their occurrence

Table 21.

—

The most important plant foods identified in 62 shoveler gizzards collected
in Illinois, 1938-1940.

Plant
occurrencl
(Number of
Gizzards)

Volume
(Cubic

Centimlters;

TOTAL PLANT

Cyperus
erythrorhizos, red-rooted nut-grnss . . .

esculenttis, chufa
strigosus, nut-grass

Cephalanthus occidcritalis, buttonbush. . .

Zea mays, corn
Ceratophyllum demersum, coontail

Echinochloa

crusgalli, wild millet

walteri, Walter's millet

Neliimbo lutea, American lotu.s

Polygonum
coccineum, marsh smartweed
pensylvanicum, large-seeded smartweed
lapathi/oliu7n, nodding smartweed ....

punctatiim, dotted smartweed
Other Polygonum

Eragrostis hypnoides, teal grass

Potamogeton
nodosus, longleaf pondweed
pectinatus, sago pondweed
Other Potamogeton

Other plants

26
4

8

24
8

12

1

1

23
4

9

4
11

1

13

3
11

45

81 J7

28.56



312 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

Table 22.—The most important animal foods identified in 62 shoveler gizzards collected

in Illinois, 1938-1940.

Animal

TOTAL ANIMAL.

BRVOZO.A statobiasts

MOLLUSCA
Gastropoda, snails

Gyrau/us parvus

Unidentified (Gastropoda

Pelecvpoda, mussels

Pisidium
Unidentified Pelecypoda

Unidentified Mollusca
ARTHROPODA
Crustacea
Copepoda, Canthocampus
Ostracoda

Insecta
Ephemeroptera, Hexagenia, mayflies

Hemiptera
Corixa, water boatmen
Unidentified Hemiptera

Coleoptera
Carabidae, ground beetles

Dytiscidae, diving beetles

(jyrinidae, whirligig beetles

Staphylinidae, rove beetles

Scarabaeidae, scarab beetles

Aphodius
distinctus

femoralis .••.•
Trichoptera, Hydroptilidae cases, caddisflies.

Diptera
Chironomidae larvae, midges
Unidentified Diptera

Unidentified Insecta

Acarina, Hvdracarina, water mites

NONFOOD, feathers

Occurrence
(Number of
Gizzards)

12

2

28

2

26

Volume
(Cubic

Centimeters)

Per Cent of
Total Organic

Contents

17.39

0.70

t

1.20

0.02
1.30
1 00

0.70
1.84

0.10

8.84
05

t

0.15
t

0.05

0.05
0.05
0.44

0.60
0.30
t

t

t

17.64

0.71

1.22

0.02
1.32
1.01

0.71
1.87

0.12

8.96
0.05

0.15

0.05

0.05
0.05
0.45

0.61
0.30

size (largest dimension) ; a few stones

were as large as 5 mm.

Wood Duck
Aix sponsa

Because the wood duck was legally pro-

tected at the time of this stud_v, only a few

gizzards of this species were available for

examination. A small sample was obtained

from confiscated birds. Twenty-six giz-

zards were collected : 9 in the period Octo-

ber 15-31 and 17 in the period November
1-15, 1938, 1939, and 1940. Seven of the

gizzards were collected from Mississippi

River stations.

A wood duck gizzard was considered

full if the gross contents amounted to 9

cc. The contents of individual gizzards

ranged in volume from 2 to 10 cc. and av-

eraged 5.6 cc. per gizzard.

The gross contents of all wood duck

gizzards collected amounted to 171.38 cc,

of which 29.00 per cent (49.70 cc.) was
grit and 71.00 per cent (121.68 cc.) was
organic substance. Of the organic mate-

rial, plant foods amounted to 99.85 per

cent and animal foods to only 0.15 per

cent, tables 23 and 24.

Plant Foods (99.85 Per Cent of Or-
ganic Contents).—The wood duck, as in-

dicated by the small sample of gizzards

collected, can be considered a vegetarian

during the fall months in Illinois. Plant

structures appeared in all the wood duck

gizzards collected. The plant contents of

individual gizzards ranged in volume from

0.8 to 9.6 cc. and averaged 4.7 cc. per giz-

zard.

Examination of the contents of the

wood duck gizzards indicated that during

I



August, 1959 Anderson: Food Habits of Migratory Ducks 313

the autumn months the wood duck diet in

Illinois is similar to the mallard diet in

that corn is the major food. In the years

of this studj', wood ducks were frequently

observed flying to and from mechanically

picked cornfields located close to the

wooded lakes and sloughs where these

ducks congregated. Twenty-two plant

species were identified in the wood duck

gizzards collected, but only eight of these

were represented by at least 1.0 per cent

each of the organic contents, table 23.

Plants of secondary importance (those

that contributed less than 1.0 per cent each

to the total organic contents of the wood
duck gizzards) were not found in large

quantities in any of these gizzards. The
only plants in this group worthy of men-
tion were the lotus and the dogwood.
Animal Foods (0.15 Per Cent of Or-

ganic Contents).—This study indicated

that animal organisms are relatively unim-
portant to the wood duck during the fall

months in Illinois, table 24.

Table 23.—The most important plant foods identified in 26 wood duck gizzards collected

in Illinois, 1938-1940.

Plant
Occurrence
(Number of
Gizzards)

Volume
(Cubic

Centimeters)

Per Cent of
Total Organic

Contents

TOTAL PLANT.

7.ea mays, corn
^iiercus

paltistris, pi n oak
Unidentified

Echinochloa cnisgalli, wild millet

Ceratophylliim

demersum, coontail

Unidentified

Cephalanthus occidentalism buttonbush.
Potamogeton

nodosus, longleaf pondweed
pectinatus, sago pondweed

Leersia oryzoides, rice cutgrass

Vitis cordifolia, frost grape
Polygonum

coccineum, marsh smartweed
hydropiperoides, mild water-pepper.
Other Polygonum

Other plants

7

1

7

10

121.50

58 87

5 80
12.40
14 70

2 80
5 10

5.21

5 20
t

4 60
2.50

1 09
0.40

t

2.83

99 85

48.38

4 77
10 19

12 08

2.30
4 19

4.28

4.27

3 78

2.05

0.90
33

2.33

Table 24.—The most Important animal foods identified in 26 wood duck gizzards collected

in Illinois, 1938-1940.

Animal
Occurrence
(Number of
Gizzards)

Volume
(Cubic

Centimeters)

Per Cent of
Total Organic

Contents

TOTAL ANIMAL.

ARTHROPODA, Insecta
Orthoptera, grasshoppers

Rhaphidophorinae
Unidentified Saltatoria

Hemiptera
Corixa, water boatmen
Unidentified Hemiptera

Coleoptera, Chrysomelidae, leaf beetles

Diabrotica undecimpunctata howardi.

.

Unidentified Coleoptera
NONFOOD, feathers

UNIDENTIFIED ANIMAL

18

t

0.02

t

0.02

0.02
0.02
0.10

(

15

0.02

0.02

0.02
0.02

08



314 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

Table 25.—The most important plant foods identified in 11 black duck gizzards collected

in Illinois, 1938-1940.

Plant
Occurrence
(Number of
Gizzards)

Volume
(Cubic

Centimeters)

Per Cent of
Total Organic

Contents

TOTAL PLANT.

Ceratophylhim demersum, coontail

Echinochloa crusgaUt, wild millet

Leerjia oryzoides, rice cutgrass

Potamogeton
nodosus, longleaf pondweed
pectinatus, sago pondweed
pusilltis, small pondweed

Zea mays, corn

Cephalanthus occidentali:>, buttonbush.

Acnida altissima, water-hemp
Polygonum

coccineum, marsh smartweed
Other Polygonum

Other plants

46.60 96.88

19.00



August, 1959 Anderson: Food Habits of Migratory Ducks 315

amounted to 3.12 per cent, tables 25 and
26.

Plant Foods (96.88 Per Lent of Or-
ganic Contents).—Plant parts appeared

in all black duck gizzards collected. The
plant contents of individual gizzards

ranged in volume from 0.1 to 8.7 cc. and

averaged 4.2 cc. per gizzard. Twenty
plant species were identified; the nine that

were considered important constituted

95.63 per cent of all organic foods, table

25.

In general, the diet of the black duck

was similar to that of the common mal-

lard. Corn might have been more im-

portant on the list of foods of the black

duck if collections had been made later in

the fall and if a larger sample had been

taken.

Animal Foods (3.12 Per Cent of Or-
ganic Contents).—Onlj' a few kinds of

animal organisms were represented in the

1 1 black duck gizzards, table 26.

Inorganic Contents (36.38 Per Cent
of Total Contents).—Gravel was present

in all black duck gizzards collected ; in in-

dividual gizzards, it ranged in volume

from a trace to 4.5 cc. Stones varied in

size from minute to 9 mm. (largest dimen-

sion) ; however, most inorganic particles

were less than 2 mm. in size.

Lesser Scaup
Aythya affinis

Lesser scaups are usually considered

omnivorous feeders, but this study indi-

cated their preference for animal foods

during the fall months in Illinois. Data
were obtained from 220 lesser scaup giz-

zards collected in the periods shown in

table 27. Of the total, 81 were from the

Mississippi River and 139 from the Illi-

nois River stations.

A lesser scaup gizzard was considered

full if its gross contents amounted to 5.7

cc. or more. The contents of individual

lesser scaup gizzards ranged in volume
from a trace to 10.5 cc. and averaged 2.86

cc. Approximately one-third of the giz-

zards were less than one-quarter full ; four

of these were empty and showed indica-

tions of lead poisoning. Only 10 were
more than three-quarters full. Fatty tissue

surrounded most of the gizzards.

Table 27.—Lesser scaup gizzards collected in Illinois in approximately 2-week periods.

1938-1940.



316 Illinois Natural History Survey Bulletin V^ol. 27, Art. 4

Table 29.—The most important animal foods identified in 220 lesser scaup gizzards col-

lected in Illinois. 1938-1940.

Animal

TOTAL ANIMAL.

BRYOZOA statoblasts

MOLLUSCA
Gastropoda, snails

Gyrauliis parvus

Viviparus viviparus

Campelonia
Lioplax subcaririata

Amnicola
feracuta

Unidentified Anwicola
{Probythinella)

bitineyana

Unidentified Amnicola {Probythinella) . .

.

Flumnicola
Somatogyrus

siibglobosus

Unidentified Somatogyrus
Pleurocera

Neritina

Unidentified Gastropoda
Pelecypoda, mussels

Sphaeriidae

Pisidium
Musculium transversu7n

Sphaerium
stamineum
Unidentified Sphaerium

Unidentified Sphaeriidae

Unionidae, fresh-water clams
Unidentified Pelecypoda

Unidentified Mollusca
ARTHROPODA

Crustacea
Cambarus virilis, crayfish

Insecta
Ephemeroptera, Hexagenia nymphs, mayflies

Odonata, Anax Junius, dragonflies

Hemiptera
Corixidae, Corixa, water boatmen
Gerridae, Gerris remigis, water striders. . .

.

Coreidae, squash bugs
Unidentified Hemiptera

Coleoptera

Carabidae, ground beetles

Dytiscidae, diving beetles

Hydrophilidae, water scavenger beetles. . .

.

Scarabaeidae, Aphodius femoralis
Curculionidae, snout beetles

Trichoptera, Hydroptilidae ca.ses, caddisflies.

Diptera

Chironomidae larvae, midges
Anthomyiidae
Unidentified Diptera

Hymenoptera, Formicidae, ants
Arachnida

Araneae, spiders

Unidentified Arachnida
NONFOOD, feathers

UNIDENTIFIED

Occurrence
(Number of
Gizzards)

2

2

16

1

15

29
1

3

2

1

11

2

57

1

27
9

12

8

23

30
2

7

1

1

1

1

6

1

1

1

1

1

2
2

T

1

2

2

1

Volume
(Cubic

Centimeters)

Per Cent of
Total Organic

Contents

369 87

0.10

13 56
0.70

1.00
20
12

10

t

50
t

0.10
t

t

20
0.29

t

08

t

10

40
t

90.35

t



August, 1959 Anderson: Food Habits of Migratory Ducks 317

The gross contents of the 220 lesser

scaup gizzards amounted to 630.26 cc, of

which 35.05 per cent (220.90 cc.) was
grit and 64.95 per cent (409.36 cc.) was
organic material. Reflecting the appar-

ently carnivorous appetite of the lesser

scaups in Illinois, animal matter amounted
to 90.35 per cent of the organic foods,

while plant structures constituted only

9.65 per cent.

Plant Foods (9.65 Per Cent of Or-
ganic Contents).—In Illinois, lesser scaup

ducks do much of their feeding on sub-

mergent vegetation at water depths of 3 to

important single plant, it was second in

importance to the pondweeds as a group.
Animal Foods (90.35 Per Cent of

Organic Contents).—Animal matter was
found in lesser scaup gizzards taken in all

collecting periods, but in greatest amounts
in those taken in the last 2 weeks of No-
vember. It was found in four-fifths of the

lesser scaup gizzards, exclusively in one-

fifth. The animal contents of individual

gizzards ranged in volume from a trace to

9.5 cc. and averaged 1.68 cc. per gizzard.

The principal animals represented in

the gizzards of lesser scaups, table 29,

Table 30.—Ring-necked duck gizzards collected in Illinois in approximately 2-week pe-
riods, 1938-1940.



318 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

marshes, and sloughs. Of the 120 ring-

necked duck gizzards collected, table 30,

7 were from the Mississippi River region

and 113 from the Illinois River valley.

A ring-necked duck gizzard was con-

sidered full if the gross contents amounted

to 8.5 cc. or more. The contents of indi-

vidual gizzards ranged in volume from 0.4

to 11.0 cc. and averaged 3.7 cc. per giz-

zard. Most of the gizzards were sur-

rounded by heavy fatty tissue.

The gross contents of the 120 gizzards

of ring-necks amounted to 445.65 cc, of

which 41.31 per cent (184.10 cc.) was
grit and 58.69 per cent (261.55 cc.) was
organic material. Plants comprised 65.93

per cent of the organic foods, and animal

matter made up 34.07 per cent, tables 31

and 32.

Plant Foods (65.93 Per Cent of Or-
ganic Contents).—Plant structures were

present in nearly all the ring-necked duck

gizzards. The plant contents of individual

gizzards varied from a trace to 9.1 cc. and
averaged 1.44 cc. per gizzard. Most of

the gizzards contained less than 2 cc. of

plant material each ; the few with more
than 2 cc. contained plant material exclu-

sively. Plant material in the gizzards of

ring-necked ducks increased from 64.10

per cent of organic contents in 1938 to

75.20 per cent in 1939, paralleling the in-

crease in duck food plants in Illinois River

valley lakes (Bellrose 1941:249-53).
Although the gizzards of ring-necks

contained some unidentifiable plant debris,

44 species of submergent, emergent, and
moist-soil plants were recognized. Seeds

and seed fragments formed the bulk of the

structures; however, the stems and leaves

of coontail and the tubers of duck-potato

and chufa were present.

The 1 1 plants most important to the

ring-neck (plants that contributed 1.0 per

Table 31.—The most important plant foods identified in 120 ring-necked duck gizzards
collected in Illinois, 1938-1940.

Plant

TOTylL PLANT.

Ceratophyllum dtmersum, coontail . . . .

Zea mays, corn

Potamogeton
noJosus, longleaf pondweed
pectinatus, sago pondweed
pusilliis, small pondweed
foliosus, leafy pondweed
graminens, variable-leaf pondweed
praelongits, white-stem pondweed
Other Potamogeton

Polygonum
coccineum, marsh smartweed . . .

lapathijolium, nodding smartweed
pensykanicum^ large-seeded smartweed.
punctatum, dotted smartweed . .

hydropiper, watet-pepper
Other Polygonum

Cyperus
erythrorhizos, red-rooted nut-grass. . . .

esculentus, chufa
Sagittaria lati/olia, duck-potato
Cephalanfhus occidentalis, buttonbush . . . .

Scirpus

fluviatilis, river-bulrush

acutus, hard-stem bulrush
validus, soft-stem bulrush
Unidentified

Sparganium
eurycarpum, giant bur-reed
Unidentified

Other plants

Occurrence
(Number of
Gizzards)

35
10

50
34
11

5

1

1

2

54
36
10

1

1

2

13

2
1

19

15

7

3

1

10

67

Volume
(Cubic

Centimeters)

172.45

45.54
36.40

20.38
8.25
3.56
3.20
0.40
0.30
0.20

13.61

1 25
0.74
0.30
0.20
0.10

7.85
0.10
6.70
3.78

3.27
0.45
0.02
0.03

1.13
2.44
12.25

Per Cent of
Total Organic

Contents

65.93

17 41



August, 1959 Anderson: Food Habits of Migratory Ducks 319

cent or more each to the organic contents

of the gizzards representing this species,

table 31) totaled almost 60 per cent of

the volume of food in the gizzards.

Parts of the secondary food plants were
found in relatively large quantities in a

few gizzards of the ring-necks, but in most
gizzards only traces or small quantities

were noted.

Animal Foods (34.07 Per Cent of

Organic Contents).—Animal matter was
found in 80 ring-necked duck gizzards and
was represented in the four collecting pe-

riods. The animal contents of individual

gizzards varied from a trace to 7.6 cc. and
averaged 0.73 cc. per gizzard. Only four

gizzards contained anin^.al food exclusive-

ly.

Of the total animal material in the giz-

zards of the ring-necks, mollusks repre-

sented more than 70 per cent by volume;
more than half of the volume of mollusks
consisted of univalves, table 32. Adults
and larvae of insects constituted nearly 25
per cent of the volume of animal matter.

Bryozoan statoblasts, fish, crustaceans,

spiders, and water mites were present in

insignificant amounts.
Inorganic Contents (41.31 Per Cent

of Total Contents).—The volume of in-

organic material in the gizzards of the

ring-necks ranged from a trace to 7 cc. and

Table 32.—The most important animal foods identified in 120 ring-necked duck gizzards
collected in Illinois, 1938-1940.

Animal

TOTJL ANIMAL.

BRYOZOA statoblasts

MOLLUSCA
Gastropoda, snails

Stagnicola

Physa
Fiviparns viviparus

Amnicola {Probythinella) binneyana
Campeloma
Fliimnicola

Somatogyriis subglobosus
Pleurocera

Unidentified Gastropoda
Pelecypoda, Sphaeriidae, mussels
Pisidium
Musculium transversum
Sphaerium

Unidentified MoLLUscA
ARTHROPODA
Crustacea, Gammartis fasciatus^ gammarid . .

Insecta
Ephemeroptera, lloagfrna nymphs, mayflies.

.

Hemiptera
Corixidae, Corixa, water boatmen . .

Relastomatidae, Benaciis nymphs, water bugs
Coleoptera

Carabidae, ground beetles

Dytiscidae, diving beetles

Gyrinidae, whirligig beetles

Scarabaeidae, Aphodiiis distinctus, scarab
beetles

Chrysomelidae, Chaetocnema, leaf beetles

Unidentified Coleoptera
Trichoptera
Diptera, Chironomidae larvae, midges
Hymenoptera, Ichneumonidae, ichneumon flies.,

Arachnida, Araneae, spiders
AcARiNA, Hydracarina, water mites

CHORDATA, Pisces

NONFOOD, feathers

Occurrence
(Number of
Gizzards >

Volume
(Cubic

Centimeters*

Per Cent of
Total Orcjanic

contenis

2

1

1

3

4
2

1

1

14

4

3

5

9

17

1

4

6

1

1

1

1

6

19

1

1

5

1

5

89.10

1.20

5.10
0.20
0.20
2.40
3.70
0.70
0.60
0.20

20.29

4.30
5.20
9.20
13.40

t

8.20

2.36
0.12

0.68
0.06
0.05

0.60
t

t

0.10
9.33
t

t

0.01

t

0,90

34.07

0.46

1.95
08
08
92

1 41

27
0.23

08
7.76

1.64
1 99
3 52

5.12

3.13

90
05

0.26
02
02

23

04
3.57

004

034'



320 Illinois Natural History Survey Hulletin Vol. 27, Art. 4

averaged 1.53 cc. per u;izzard. Gravel par-

ticles ranj^ed in size from minute to 13

mm. (largest dimension). In 80 per cent

of the gizzards, grit particles seldom ex-

ceeded 3 mm, each. Apparently calcareous

shell material served as grit, for gravel

was absent from many gizzards.

Ganvasback
. yy / liya i 'a lisineria

The canvasback is an omnivorous feeder

in Illinois, this study indicated. Many of

the canvasback gizzards collected (61 per

cent) contained only vegetable matter,

while a few (8 per cent) contained animal
matter exclusively. Because few canvas-

backs were killed in Illinois while field

work for this study was being done, only

a small number of canvasback gizzards

were collected. Of the 2S collected, 18

were obtained in 1938, 9 in 1939, and 1

in 1940; 4 of these were from the Mis-
sissippi River area. One gizzard was taken

in the period October 15-31, 13 in No-
vember 1—15, 13 in November 16-30, and
1 in December 1-15.

Table 33.—The most important plant foods identified in 28 canvasback gizzards collected

in Illinois. 1938-1940.

Plant



August, 1959 Anderson: Food Habits of Migratory Ducks 321

Table 35.—The most important plant foods identified in 14 redhead gizzards collected in

Illinois, 1938.

Plant
Occurrence
(Number of
Gizzards)

Volume
(Cubic

Centimeters)

Per Cent of
Total Organic

Contents

TOTAL PLANT.

Potamogeton
nodosHS, longleaf pondweed
pectinatHS, sago pondweed
Other Potamogeton

Ceratophylluni demersum, coontail

F.chinochloa crusgalli, wild millet

'Aea 7nays, corn

Polygonum
coccineum, marsh smartweed
lapathifolium, nodding smartweed
pensyhanictim, large-seeded smartweed.
pu)ictatum, dotted smartweed

Scirpus

validus, .soft-stem bulrush

fluviatitis, river-bulrush

Ambrosia
artemisii/olia, common ragweed
Unidentified

Other plants

40 30 77.93

7,03
27

t



322 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

Table 36.—The iTiu!>t important animal foods identified in 14 redhead gizzards collected in

Illinois, 1938.

Animal
Occurrence
(Number of
Gizzards j

Volume
(Cubic

Centimeters

Per Cent of
Total Organic

Contents

TOTAL ANIMAL.

BRVOZOA statoblasts

ARTHROPODA
Insfcta

Ephemeroptcra, Hexagenia, mayflies .

Hemiptera, Corixa, water boatmen. . .

Coleoptera, Dytiscidae, diving beetles.

Trichoptera

Lepidoptera
Diptera, Chironomidae larvae, midges.

Arachnida
Argiopoidea, spiders

Unidentified Arachnida
AcARiNA, Hydracarina, water mites

NONFOOD, feathers

11.41

0.30
0.01

t

1.50
0.09
9.50

0.01

t

t

t

2^.07

0.58
0.02

2.90
0.17
18.37

0.02

the gizzards collected contained this vol-

ume of material. Gross contents of indi-

vidual gizzards ranged from 3.2 to 10.0

cc. each and averaged 6.47 cc. per gizzard.

Of the 90.61 cc. of material, 42.93 per

cent (38.90 cc.) was grit and 57.07 per

cent (51,71 cc.) was organic substance.

Plants contributed 77.93 per cent of the

organic contents and animal organisms

22.07 per cent, tables 35 and 36.

Plant Foods (77.93 Per Cent of Or-
ganic Contents).—Plant structures were
found in 13 of the 14 redhead gizzards;

the plant contents of individual gizzards

ranged in volume from 0.8 to 6.9 cc. and
averaged 3.1 cc. per gizzard. The bulk of

the material consisted of longleaf pond-

weed seeds. Nineteen food plants were
identified ; six species contributed at least

1.0 per cent each to the organic contents,

table 35. Seeds of the alkali bulrush, a

western species not indigenous to Illinois,

were found in one gizzard.

Animal Foods (22.07 Per Cent of

Organic Contents).—Animal organisms

were present in 12 of the 14 redhead giz-

zards; the animal matter in individual giz-

zards ranged from a trace to 4.3 cc.

Midges were found in six of the gizzards,

table 36.

Inorganic Contents (42.93 Per Cent
of Total Contents).—The grit contents

of individual gizzards of the redhead

ranged from 0.9 to 4.8 cc. and averaged
2.78 cc. per gizzard. A major portion of

the inorganic material consisted of quartz

particles varying in size from minute to 2

mm. (largest dimension) ; the material in-

cluded an occasional stone up to 11 mm.

Ruddy Duck
Oxyura jamaicensis

Only five ruddy duck gizzards were col-

lected for this study. All were obtained

between October 15 and November 15,

1939 and 1940. The gross contents of

these gizzards amounted to 16.6 cc, of

which 63.86 per cent (10.6 cc.) was grit

and 36.14 per cent (6.0 cc) was organic

material. Of the organic food, plant struc-

tures amounted to 23.33 per cent and ani-

mal matter to 76.67 per cent.

Plant Foods (23.33 Per Cent of Or-
ganic Contents).—Plant parts appeared

in three of the five ruddy duck gizzards;

only a trace in two and 1.4 cc. in the other.

Four species of plants were represented

:

coontail made up almost 100 per cent of

the bulk; longleaf pondweed, leafy pond-

weed, and wild millet appeared as traces.

Animal Foods (76.67 Per Cent of

Organic Contents).—Animal structures

were found in all five ruddy duck giz-

zards. The animal contents of individual

gizzards ranged from a trace to 1.7 cc.

Midge larvae comprised almost 100 per

cent of the animal matter; water boatmen
and water beetles appeared as traces.

Inorganic Contents (63.86 Per Cent

of Total Contents).—Gravel made up



Au-rust, 1959 Anderson: Food Habits of Migratory Ducks 323

nearly two-thirds of the gross contents of

the ruddy duck gizzards. The inorganic

contents of individual gizzards ranged

from ] .2 to 4.0 cc. and averaged 2.1 cc.

Most gravel particles were each smaller

than 2 mm. (largest dimension).

Common Goldeneye
Bucephala clangula

Only three goldeneye gizzards were ob-

tained for this study, all of them in the

period November 14-30, 1938. The total

gross contents amounted to 2.6 cc, of

which 50.00 per cent (1.3 cc.) was grit

and 50.00 per cent (1.3 cc.) was organic

material. Longleaf pondweed, which con-

stituted 15.38 per cent of the organic con-

tents, was the only important plant species

represented, while mayfly nymphs, which
constituted 84.62 per cent of the organic

contents, was the only animal food.

Greater Scaup
Ay thya marila

The gizzard of one greater scaup was
collected on November 16, 1940. It con-

tained grit material amounting to 1.0 cc.

and no animal or plant structures.

Oldsquaw
Clausula hyemalis

The gizzard of one oldsquaw duck was
obtained in the fall of 1940. It contained

2.7 cc. of material, of which 11.11 per

cent (0.3 cc.) was grit and 88.89 per cent

(2.4 cc.) consisted of plant and animal
matter. Coontail made up the entire plant

contents (41.67 per cent of the organic

material), while fish bones, midges, and
snails made up the animal contents (58.33
per cent of the organic material).

PLANT FOODS

Data derived from analjses of the con-

tents of waterfowl gizzards collected in

Illinois in the autumns of 1938, 1939, and
1940 were used in making evaluations of

the most important plants utilized as food

by waterfowl migrating through the state.

Although no completely satisfactory

evaluations of the importance of various

kinds of food plants are possible, a rough

evaluation of each of the most important

kinds was given by an index figure ob-

tained by multiplying the number of giz-

zards in which the kind of plant was found

(occurrences) by the actual figure indi-

cating the percentage it constituted of the

total plant volume (for example, for Zea
mays, multiplying 1,445 by 39.36, figures

derived from table 38).

The nineteen species of plants that were
most utilized by ducks in their southward

migrations through Illinois are listed m
table 37. These plants were the favored

Table 37.—Occurrence-percentage index ratings of plant foods identified in duck gizzards
collected along the Illinois River, Ottawa to Florence (4,505 gizzards), and along the Missis-

sippi River, Rock Island to Quincy (472 gizzards), 1938-1940 (derived from table 38).

Plant Index
Number

Zea mays, corn
[.eersia oryzoides, rice cutgrass

Polygonum coccineum, marsh smartweed
Ccratophyllum demersum, coontai!

Erhinorhloa crusgalli, wild millet

Potanwgeton nodosus, longleaf pondweed
Cyperiis erythrorhizos, red-rooted nut-grass
Acnida altissima, water-hemp
Polygonum lapathi/oliiim, nodding smartweed
Cephalanthiis occidentalism buttonhush
Polygonum pensylvanicum, large-seeded smartweed
Cyperus strigosus, nut-grass
Cyperus esculentus, chufa
Echinochloa walteri, Walter's millet

Potamogeton pectinatus, sago pondweed
Sagittaria latifolia, duck-potato
Scirpus fluviatilis, river-bulrush

E*-agrostis hypnoides, teal grass

Sparganium euryrarpum, giant bur-reed

56,875
1

1
, 862

8,249
7,734
4,605
2,293
2,289
1,849
1,111
956
635
605
554
537
427
232
156
116

112



324 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

Table 38.— Plant foods of clucks taken along the Illinois River, Ottawa to Florence (4,505

gizzards), and along the Mississippi River, Rock Island to Quincy (472 gizzards), 1938-1940.

Plant

Illinois River

Occur-
rence

(Number
of Giz-

zards)

Volume
(Cubic
Centi-

meters)

Per Cent
of

Organic
Contents

Mississippi River

Occur-
rence

(Number
of Giz-

zards)

Volume
(Cubic
Centi-

meters)

Per Cent
of

Organic
Contents

TOT.-ll. PLANT.

Zea tnays, corn

I.eersia oryzoides, rice cutgrass

Ceratophvlliim demersum^ coontail. . . .

Echinochloa
irKsgalli, wild millet

wa/teri, Walter's millet

Unidentified

Cvperus
ervt/irorhizos, red-rooted nut-grass..

strigosiu, nut-grass.

fscu/entiis, chufa

ferax

Unidentified

Polygonum
coccineuni, marsh smartweed
lapathifolinm, nodding smartweed.

,

pensyIvan icum, large-seeded smart-

weed
hydropiperoides, mild water-pepper.

punctatum, dotted smartweed
persicaria, lady's thumb
hydropiper, water-pepper
scandens, climbing false buckwheat
sagittatum, arrow-leaved tearthumb
amphibium, water lady's thumb...
aviculare, prostrare knotweed
Unidentified

Potamogeton
nodosus, longleaf pondweed
pectinatus, sago pondweed
foliosus, leafy pondweed
pusi/lus, small pondweed
perfnliatus, thoroughwort pondweed
praelongus, white-stem pondweed .

ampli/olius, large-leaved pondweed
epihydrus, ribbon-leaf pondweed
grarfiineus, variable-leaf pondweed .

Unidentified

Acnida altisiima, watcr-henip
Sagittaria

lalijolia, duck-potato
cuneata, wapato
Unidentified

Cephalanthus occidentalism buttonbush
Eragrostis

hypnoides, teal gra.ss

Unidentified

Triticum aestivum, wheat
Lemna

minor, lesser duckweed
Unidentified

1,262
880
795

669
243

2

613
378
384

3

20

1,995
1,028

480
219
173

101

61

7

2

1

17,234.88

6,429.05
2,339.58
1,751.63

1,165.32
410.67

1.40

683.11
289.13
267.42
0.20
47.78

760.02
161.01

141.63
82.32
35.31
11.71
6.75
0.33
0.20
0.05

15

1,252
596
179

98

3

5

44
691

156

660

114
2

46

152

2

2.71

329.65
104.22
40.03
17.76
8.40
1.70
0.11
0.05

"2'. 04
494.59

254.41
0.50
1.31

252.88

188.71
0.40

169.90

95.91
3.20

94.82

35.38
12.87
9.64

6.41
2.26
0.01

3.76
1.59
1.47

t

0.26

4 18

0.89

0.78
0.45
0.19
0.06
0.04
t

t

t

0.01

1.81

0.57
0.22

10

0.05
0.01

t

t

0.01
2.72

1.40
t

0.01
1.39

1.04

t

0.93

0.53
0.02

183

41

14

46

1,342.78

883.20
52.62
24.10

30.22

17

117

119

6

36
15

28
4
1

3

1

4

22
34
42
6

2

1

5

4

11

30

6.90
3.60
t

0.70

1.32
19.65

56.19
0.40
21.36
6.25
4.00
0.15
0.40
0.02
t

1.70

5.40
21.77
14.10
0.87

1.30
0.40
0.20
0.32

3.44

4.77

4.40

8.30



Auj^ust, 1959 Anderson : Food Habits of Migratory Uucks 325

Table 38.

—

Continued.

Plant

Sparganium
enrycarpuj)!^ giant bur-reed

Unidentified

ScirpHS

flNviatilis, river-bulrush

iitrovirens, green bulrush

aciitiis, hard-stem bulrush

validtis, soft-stem bulrush

palndosiis, alkali bulrush

aniericanus, American bulrush. .

.

Unidentified

Algae
Netumbo lutea, American lotus

^ne7rns
alba, white oak
palustris, pin oak
Unidentified acorns

Fagopyrum sagittatitm, common buck-
wheat

Rumex

altissimus, pale dock
acetosella, field sorrel

Unidentified

Bidens

frondosa, beggar-ticks

Unidentified

Ambrosia
arteniisii/olia, common ragweed . .

.

trifida, great ragweed . . .

psilostachya, western ragweed
Unidentified

Najas
guadalupcnsis, southern naiad . .

flpxilis, northern naiad
Unidentified

Eleocharis

palustris, common spike-rush. .

obtiisa, blunt spike-rush. . . ...
parvula, dwarf spike-rush

Unidentified

Heteranthera dubia, mud-plantain . .

Junciis, bog-rush
Bark, roots, and wood
Raniinculn. , buttercup
Nymphaea tuberosa, yellow water-lily

Chenopodiiim
album, lamb's-quarters
Unidentified

Alisma subcordattim, water-plantain

.

Salix, willow
Cornus, dogwood
Lippia lanceolata, fog-fruit

Vigna sinensis, cow-pea.
Myriophyllum

heterophyllum, water-milfoil

Unidentified

Illinois River

Occur-
rence

(Number
of Giz-

zards^

286
134

464
3

171

72
5

2

45

43

62
1

10

11

29

28
20
85

1

18

16

3

69
99

1

8

5

24
8

7

10

12

1

1

16

75
219

1

10

60

Volume
(Cubic
Centi-

meters)

60.36
31.74

47.97
9.50
8.90
3.58
3.30

1.63
58.29
55.60

16.90

38.10

37.40

27.05
t

0.08

20.68
1.95

7.94
7.55
1.07
0.65

14.35
1.10
1.30

8.44
4.22
2^00

t

14.30
12.58
8.15
8.10
6.58

6.41

t

6.20
6.17
6.04
5.60
5.20

0.50
4.23

Per Cent
of

Organic
Contents

0.33
0.17

0.25
0.05
0.05
0.02
0.02

0.01
0.32
0.31

0.09

0.21

0.21

0.15

0.11

0.01

0.04
0.04

t

t

0.08

t

0.01

0.05
0.02
0.01

0.08
0.07
0.04
0.04
0.04

0.04

0.03
0.03
0.03
0.03
0.03

t

0.02

Mississippi River

Occur-
rence

(Number
of Giz-

zards)

24
16

46

52

27
5

5

1

9

1

II

20

Volume
(Cubic
Centi-

meters)

26

6 57
6.61

8.83

14.39
2.10
1.80
2.30
0.70
21.50
1.00

5.80
12.40

11.60
t

0.50

0.73
0.10

0.10
0.20

t

0.50

Per Cent
of

Organic
Contents

0.80
1.31

1.03

2.60



326 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

Table 38.—Continued.

Plant

Illinois River

Occur-
rence

(Number
of Giz-

zards)

Volume
(Cubic
Centi-

meters^

Per Cent
of

Organic
Contents

Mississippi River

Occur-
rence

(Number
of Giz-

zards )

Volume
(Cubic
Centi-

meters)

Per Cent
of

Organic
Contents

Sparlhia pecli)iata, prairie cord-grass .

Carex
rostrata, beaked sedge

I'nidentified

LophotocarpHS
Ipomea hederacea, ivy-leaved morning-

glory .

Zauuichellia paliistris, horned pond-
weed

Sida spinosa, prickly sida

Gramincac
Paspahitu

ciliatifoliiivi, ciliate-leaved

paspalum
Unidentified

Vitis

rordifolia, frost grape
Unidentified

Potentilla, cinquefoil

Di^itaria

sanguirialis, crab-grass

ischaemum, smooth crab-grass

Anacharis canadensis, waterweed
Panicum

dichotomiflorum , fall panic-grass.. . .

capiUare, old- witch grass

Bean, navy
Verbena

hastata, blue vervain

Unidentified

Ahntilon theophrasli, velvet-leaf

Hibiscus

militarise scarlet rose-mallow
Unidentified

Setaria

itaiica, German millet

glanca, yellow foxtail

viridis, green foxtail

Ce/tis occidentalis, hackberry
Compositae
Crataegus e hawthorn
So/annm, nightshade
I.egiDiiinosae

Rhus
glabra, smooth sumac
radicans, poison ivy

Unidentified

Phaseolus, wild bean
Strophostyles

helvola, trailing wild bean
Unidentified

Pontederia cordata, heart-shaped
pickerelweed

Cladium mariscoides, twig-rush

Cassia fasciculata, partridge-pea ....

4maranthus
retroflexus, green amaranth
Unidentified

33
12

35

5

34
2

2

?

4
56

1

3

4
1

38
IS

1

1

4
37

2

5

3

17

1

1

1

4.20

4.13
4.10

4 04

3 . 60
3.56
3 30

3.25
t

0.25
2.82
3.00

2.50
0.30
2.10

1.90
0.11
1.50

0.80
0.05
0.83

0.50
0.06

6.40
0.50
t

0.50
0.40
0.30

30
0.30

0.18
0.10
t

0.20

0.10
t

0.08
0.07
0.03

t

0.01

0.02

0.02
0.02

0.02

0.02
0.02
0.02

0.02

t

0.02
02

0.01
t

0.01

0.01

t

0.01

t

t

t

t

t

0.04
t

0.10
3.20

0.20

1.50

2.50
17.72

0.30
0.50

4.90
t

0.03

0.10
t

0.20
t

t

0.04



August, 1959 Anderson: 1'OOd Habits of Migratory Ducks 327

Table 38.

—

Continued.

Plant

Illinois River

Occur-
rence

(Number
ot Giz-

zards)

Volume
(Cubic
Centi-

meters)

Per Cent
of

Organic
Contents

Mississippi River

Occur-
rence

(Number
of Giz-

zards;

Volume
(Cubic
Centi-

meters)

Per Cent
of

Organic
Contents

Ruins
flagellmis, northern dewberry
Unidentified

Ammannia cocciuea, tooth-cup

Avena sativa, oats

Convolvulus arvensis, field-bindweed

.

Cuscnta, dodder
Diodia teres, buttonweed
Geum, avens
Phytolacca americana, common
pokeweed

Po'tulaca, purslane

Rosa, rose

Sorghum vu/gare, sorghum
Prunns, cherry

Symphoricarpos orbiculatus, coral-

berry

Trifoliiim, clover

Unidentified plant

0.02
t

1

73

t

63 68 0.35

3

23

3.10

t

0.10

t

2.30

1.40

1.10

18.09

0.21

o'oi

0.15

0.09

0.07

'l"22

ones in each of the 3 years of this study
;

from year to year the relative positions of

some of them changed within the group as

a result of changes in abundance or acces-

sibility.

Food plants favored by the various spe-

cies of ducks differed with the feeding hab-

itats of the birds. Foods utilized by ducks

of the teal size were mainly from small-

seeded plants, while those utilized by the

mallard were principally from corn and
from large-seeded native wild plants. The
puddlers fed principally on emergent and

moist-soil plants, while the divers fed

largely on submergent plants. There were
exceptions in each waterfowl group, how-
ever, such as the gadwall and the baldpate,

which fed primarily on a submergent

l^lant, coontail, and the ring-necked duck

and the redhead, which fed extensively on

emergent plants.

Of the plants represented in the giz-

zards collected for this study, 95 native

wild plants and 4 domestic plants were

identified to species, table 38. The 19 im-

portant species listed in table 37 and dis-

cussed in the following pages constituted

92.91 per cent of the total plant material.

Analyses of gizzard contents showed that

the plants increased or decreased in use-

fulness to ducks during the fall season as

weather conditions and water levels var-

ied.

Corn
7jea Tuays

Corn was the most important food both

in volume and in number of duck gizzards

in which it was found (occurrences), table

38. It comprised 37.20 per cent of all or-

ganic foods in the gizzards, primarily be-

cause it was the staple food of the mallard,

which made up over 50 per cent of the

duck flight. It appeared in 1,445 gizzards,

of which 86.92 per cent were mallard and

9.55 per cent were pintail. Of the 26

wood duck gizzards that were collected,

1 1 contained corn.

Use of this grain depended largely upon

the time of corn harvest. In 1939, corn

ripened early, and harvesting was well

along by October 15; in that year, mal-

lard gizzards collected early in the season

were gorged with kernels of waste corn.

However, in 1940, corn harvesting did

not commence until late in October or

early November, and native wild foods

appeared in gizzards in large volumes until

the waste corn was available. The volume

of corn increased from October 16 to De-



328 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

cember 15, even though the number of

duck gizzards containing corn decreased.

Rice Gutgrass
Leersia oryzoules

Rice cutgrass, fig. 6, was shown by

this study, tables 37 and 38, to be the

most important wild native food plant in

Illinois during the autumn. This plant

was spotty in distribution, but apparently

wherever the seeds, rootstocks, and tender

shoots were accessible they were avidly

consumed. Pintails and mallards were the

most important consumers. As many as

2,000 seeds were taken from a single pin-

tail gizzard.

Plant structures of rice cutgrass, found

in 921 duck gizzards, comprised 12.17 per

cent of the entire organic contents of the

4,977 gizzards examined. Rice cutgrass

provided a good, staple food throughout

the fall months. The volume of rice cut-

grass structures in gizzards decreased

gradually from 16.83 per cent of the plant

Fig. 6.—Rice cutgrass {Leersia oryzoides), known also as saw-grass. This plant grows on
moist soil in shallow water. Ducks feed on the seeds and rootstocks.



August, 1959 Anderson: Food Habits of Migratory Ducks 329

foods in late October to 11.75 per cent in

early December.

Marsh Smartweed
Polygonum coccineum

Marsh smartweed, fig. 7, ranked fourth

among wild native food plants in percent-

age of total organic contents of the duck

gizzards examined, table 38 ; it was second

among wild plants and third among all

plants in the occurrence-percentage index

rating, table 37. In the region and years

of this study it was an abundant plant, but

in much of the region it was low in seed

production. In a few areas where water

level conditions were favorable, it pro-

duced an abundance of seeds in 1938 and

1939. Because of sporadic seed production

(Low & Bellrose 1944:14), this plant

varied from year to year in usefulness as

a source of duck food. All important spe-

cies of ducks fed on the seeds, but these

seeds seldom made up the bulk of the plant

food for any one duck.

Marsh smartweed seeds were found in a

large number of gizzards (2,012), but

Fig. 7.—Marsh smartweed [Polygonum coccineum), sometimes called redtop because of its

pink-red blossoms. When it grows in water 6 to 18 inches deep it produces seed that rates high

as duck food.



330 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

never in large quantities. Because the

seeds drop early in the fall, this smartweed

is considered a good early season source of

food. In October, this plant represented

5.50 per cent of the plant food but, by

early December, only 1.85 per cent.

Marsh smartweed rated as an important

baldpate and gadwall were the most avid

feeders. During October, when waste
corn was scarce, mallards fed extensively

on coon tail.

Coontail structures, which were found

in 809 gizzards, represented 9.03 per cent

of the total organic contents of all giz-

Fig. 8.—Coontail or hornwort {Ceratophyllum demerstim) . A favorite food of baldpates,
gadwalls, and ring-necked ducks, it grows best in stable or semi^table waters that are fairly

clear and protected from wave action. Ducks feed principally on the leaves and stems.

waterfowl food plant despite the relatively

small quantities of its seed ingested by in-

dividual birds.

Coontail
Ceratophylluni demersum

Coontail, fig. 8, which occurred com-
monly in all stable and semistable water
areas involved in the study, ranked second
among wild native food plants in percent-

age of the total organic contents of all duck
gizzards examined, table 38, but it rated

fourth in the occurrence-percentage index,

table 37. Seed production of coontail was
low in the years of this study ; leaves and
stems were the principal structures found
in the gizzards. This study showed that

all species of ducks of which there was an
adequate sample fed uppn this plant; the

zards. Analyses showed that utilization of

coontail rapidly decreased during the fall

season, from 16.84 per cent of the volume
of plant foods in October to 2.20 per cent

in December. Despite the decrease in vol-

ume, coontail appeared to be an important

source of food through most of the fall.

Wild Millet
Echinochloa crusgalli

Because some difficulty was experienced

in separating the seeds of wild millet from

the seeds of Japanese millet, EchinocJiloa

frujuentacea, undoubtedly some seeds

classified as wild millet were those of the

Japanese species. However, in the years

in which gizzards were collected for this

study, the acreage of Japanese millet in

Illinois was comparatively small.



August, 1959 Anderson: Food Habits of Migratory Ducks 331

Wild millet, fig. 9, ranked third among
wild native food plants in percentage of

the total organic contents of all duck giz-

zards examined, table 38. Although its

occurrence was spotty in the Illinois and
Mississippi river valleys in the years of

this study, it ranked fifth in the occur-

rence-percentage index, table 37. During
1939 and 1940, water level conditions in

some areas were very favorable for luxuri-

ant growth and heavy seed production of

millets (Bellrose 1941:253). Seeds of

the wild millet were found in the gizzards

of most ducks and were especially numer-
ous in those of pintails, mallards, and
green-winged teals. A few pintail gizzards

held as many as 1,000 seeds each, and the

craws another 3,500.

Wild millet seeds or other plant parts

appeared in 715 gizzards and constituted

6.08 per cent of the total organic contents

of the gizzards examined. The heaviest

consumption of wild millet occurred in

October, when this plant represented

10.76 per cent of the plant foods in the

gizzards; the consumption decreased to

3.90 per cent by December, probably as a

result of a decline in availability of millet

seed and a shift by the mallard and the

pintail to a corn diet.

Because the seeds remained on the

plants until late fall, wild millet proved
to be an excellent source of food for ducks

;

also, the rank stem growth provided pro-

tective cover.

Longleaf Pondweed
Potamogeton nodosus

The longleaf pondweed, fig. 10, is con-

sidered one of the good duck food plants

Fig. 9.—Wild millet [Echi-

iincliloa criisgalli). Known
also as barnyard-grass, this

moist - soil plant produces
seeds that are consumed in

large quantities by mallards,
pintails, teals, and other

ducks. The inset shows wild
millet growing on a mud flat

from which water has re-

ceded. In 1939 and 1940,

water levels along the Illi-

nois River were especially

favorable for growth and
seed production of millets.

The millets provide cover as

well as food for ducks.



U2 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

in many parts of the United States. In

Illinois, it was present in small amounts in

nearly all the river-bottom lakes in the

rej^ion and years involved in the present

stud\ ; usually it produced an abundance

of seed. In the j^izzards of all important

species of waterfowl included in this re-

port, the seeds and occasionally the stems

or leaves were found.

Longleaf pondweed plant parts, found

in 1,274 gizzards, amounted to 1.70 per

cent of the total orjjanic contents of all

gizzards examined, table 38. It ranked

sixth in the occurrence-percentage index,

table 37. Apparently, use of this plant

varied from one period to another, but at

no time did it constitute more than a sup-

plemental food.

Red-Rooted Nut-Grass
Cyperus erythrorhizos

Red-rooted nut-grass, a moist-soil plant

that grows on mud flats and mud banks

of both the Illinois and Mississippi river

valleys, ranked sixth among food plants

in percentage of total organic contents of

gizzards examined, table 38, and seventh

in the occurrence-percentage index, table

37. Because growing conditions were

much better for plants of this tvpe in 1939
and 1940 than in 1938 (BelJrose 1941:
252-3), the volume of seed and its acces-

sibility to ducks was greater. This nut-

grass was found in significant amounts in

the gizzards of several of the important

duck species; it made up the largest per-

centages of organic material in gizzards of

the blue-winged teal, green-winged teal,

and shoveler. In most cases, the entire

seed head had been clipped off; in other

cases, individual seeds had been strained

from the bottom ooze or from the water
surface. Some pintail gizzards contained

amounts estimated at 25,000 seeds each.

This plant was represented in 617 giz-

zards, table 38, and constituted 3.71 per

cent of the plant contents or 3.51 per cent

of the total organic contents of all duck
gizzards examined. There appeared to be

little change in the rate of its utilization

as the fall months advanced. This nut-

grass appeared to be an excellent all-season^

duck fcod.

Water-Hemp
Acnida altissirna

Water-hemp, or pigweed, fig. 11, ani

important moist-soil plant that occurs on

Fig. 10.—Longleaf pondweed {Potamogeton nodosus), known also as deer's tongue. Ducks
feed on the seeds of this plant.



Au-ust. 1959 Anderson: Food Habits of Migrato.'^y Ducks 333

Fig. 11.—Water-hemp or pigweed {Acnida
altissima) . This plant grows well on mud
flats.

mud flats, ditchbanks, and similar areas,

is a good source of duck food in seasons

favorable to its growth. It ranked eighth

in the occurrence-percentage index, table

37. This plant is subject to poor seed

yields when growing conditions are un-

favorable, such as occurred in 1938 and
1939. In those years, it was represented

in only about 1 per cent of the total or-

ganic contents of the duck gizzards exam-

ined, but in 1940, a year in which beds

were abundant and luxuriant, its volume
increased to 8.18 per cent. The puddle

ducks, especially the mallard, pintail, and

both teals, used this plant. It was not un-

common to find 40,000 seeds in a mallard

gizzard, or 25,000 to 30,000 in a pintail

or teal gizzard. Only the seeds and seed

heads of this plant were used.

Water-hemp seeds or seed heads, found

in 695 gizzards, table 38, made up 2.52

per cent of the total organic contents of all

gizzards included in this study. Appar-

ently, the usage of this food plant through-

out the fall changed little as long as the

seeds were accessible. An early freeze

would probably have lessened its use, but

the 1938-1940 study did not indicate any
decrease in percentage of use as the season

progressed. Water-hemp can be consid-

ered a good all-fall food for most species

of dabbling ducks.

Nodding Smartweed
Polygo n um Iapath ifoliu in

Nodding smartweed, fig. 12, grew abun-
dantly along the margins of most Illinois

rivers and bottomland lakes in 1938-
1940. Gizzard analyses showed that most
of the important species of waterfowl fed

on the seeds in significant amounts. Seed,

produced in abundance, seemed to serve

principally as a supplemental food, as it

never constituted a complete feeding.

Seeds of nodding smartweed, present in

1,145 gizzards, table 38, constituted 0.92

per cent of the total organic contents of

all gizzards examined. The period of

Fig. 12. — Nodding smartweed {Polygonum
lapathifolium) . The long, drooping, densely

flowered spikes distinguish this plant from
other smartweeds.



334 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

greatest consumption occurred the latter

half of October; during the fall the pro-

portion of these seeds in the gizzards

dropped from 1.62 per cent to 0.56 per

cent of the plant foods.

This smartweed can be considered only

a fair source of all-fall food, except lo-

Fig. 13.—Large-seeded smartweed {Polyg-
onum pensylian'uum), known also as Penn-
sylvania smartweed. A moist-soil plant, this
smartweed ranked below marsh smartweed
and nodding smartweed as an Illinois duck
food in the years of this study.

cally where the plant is easily accessible.

It ranked ninth in the occurrence-percent-
age index, table 37.

Buttonbush
Cephalanthus occidentalis

This shrub is very abundant in the val-

leys of both the Illinois and the Mississippi

rivers. Even though its seeds are a fair

duck food, the buttonbush is not a desira-

ble plant to have in a waterfowl habitat,

as it tends to crowd out more favorable

duck food plants. However, this shrub is

less undesirable in a waterfowl habitat

than lotus or river bulrush, which have lit-

tle value as duck food plants. Seeds of the

buttonbush were found in small quanti-

ties in the gizzards of all important spe-

cies of dabbling ducks.

Present in 690 gizzards, the seeds of the

buttonbush represented 1.31 per cent of

the total organic contents of all gizzards,

table 38. Throughout the fall season, the

percentage of seeds consumed varied very

little from week to week. Buttonbush may
be considered as a fair supplemental duck

food plant, table 37.

Large-Seeded Smartweed
Polygonum pensylvanicum

The large-seeded smartweed, fig. 13,

ranked eleventh in the occurrence-percent-

age index, table 37. Utilization of this

plant by ducks in Illinois was subject to

change from year to j^ear and place to

place and was dependent principally on ac-

cessibility. For instance, along the Mis-
sissippi River, where this smartweed ap-

peared to be easily accessible during the

years of this study, it ranked first among
native foods, table 38. The seed was the

only part of this plant found in the duck
gizzards examined.

Seeds of this smartweed, in 599 giz-

zards, table 38, made up 1.01 per cent of

the entire organic contents of all gizzards.

Apparently the seeds were eaten through-

out the fall, but were more important in

the diet during the latter part of Novem-
ber and December than at other times.

Nut-Grass
Cyperus strigosus

Like the red-rooted nut-grass, this spe-

cies grows on certain mud flats and other

moist areas. It ranked high among the im-

portant foods preferred by the pintail,

blue-winged teal, and green-winged teal

in the years of this study. Apparently both

seeds and seed heads were avidly con-

sumed. Some pintail and teal gizzards

contained as many as 10,000 seeds each.

Structures of this plant, found in 384
gizzards, constituted 1.58 per cent of the

total plant contents and 1.49 per cent of

the total organic contents of the gizzards

examined, table 38. Apparently heaviest



August, 1959 Anderson: Food Habits of Migratory Ducks 335

Fig. 14.—Chufa {Cyperns esculentus) , one
of several nut-grasses that grow on moist soil

in Illinois. Ducks feed upon the seeils and
tubers.

use of this plant occurred durinj^ Novem-
ber, when its principal consumers were
most abundant.

As with most moist-soil plants, in \'ears

and in places in which the seed was pres-

ent and accessible, this nut-grass was a

good source of waterfrwl food dur:n;j: the

fall months. It ranked twelfth in the oc-

currence-percentage index, table 37.

Chufa
Cypenis esculentus

Chufa, fig. 14, occurred rather sporad-

ically on mud flats, ditchbanks, and other

moist ground in the areas from which giz-

zards were collected. It was a preferred

food of the blue-winged teal, green-winged

teal, and pintail, which consumed seeds,

seed heads, and tubers. Several hundred

seeds were taken from a few of the teal

gizzards.

Structures of this plant were found in

385 gizzards and constituted 1.36 per cent

of the total organic contents of the giz-

zards examined, table' 38. As with the

other moist-soil plants, chufa received the

heaviest use during November. This nut-

grass furnished good waterfowl food dur-

ing the fall months when water conditions

made the plants accessible. It ranked third

among nut-grasses in the occurrence-per-

centage index, table Zl

.

Walter's Millet
Echinochloa walteri

Although the seeds of Walter's millet,

fig. 15, are much smaller than those of the

wild millet, they were eagerly consumed
by the ducks represented in this study.

Walter's millet often volunteers in muck
areas generally wetter than those contain-

ing wild millet. Seeds of Walter's millet

were found in the gizzards of most puddle

ducks— in relatively largest am.ounts in

gizzards of the pintail, green-winged teal,

and blue-winged teal. The fruit is more

Fig. 15.—Walter's millet (Echinochloa ival-

teri), sometimes called corn grass. Its small

seeds are consumed in considerable numbers
by mallards, pintails, and teals.



336 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

persistent than that of the wild millet and

is therefore available for waterfowl later

in the season.

Walter's millet was represented in 243

stomachs, table 38, and constituted 2.09

per cent of the total organic contents of

all {gizzards. It is a jjood source of late-

fall waterfowl food, it ranked fourteenth

in the occurrence-percentage index, table

37.

Sago Pondweed
Potamogeton pectinatus

Sago pondweed, fig. 16, according to

Martin c^' Uhler (1939) is one of the

most important duck food plants in the

United States. In 1938-1940, this plant

appeared to be relatively unimportant in

Illinois; here the plant was spotty in dis-

tribution and it produced verv little seed

(Bellrose 1941:266). Although sago

ranked low among the important plants in

the present study, table 37, most species of

ducks, especially the divers, fed on the

limited seed supply, tubers, and leaf struc-

tures.

Portions of the plant, found in 630 giz-

zards, represented only 0.64 per cent of

the total organic contents of all gizzards

examined, table 38. In no half-month pe-

riod did it vary considerably in volume or

number of occurrences from the average.

If this plant had been more abundant
and if it had produced more seed, it un-

doubtedly would have ranked much higher

in the food preference list.

Duck-Potato
Sayittaria latifolia

The duck-potato, fig. 17, was shown by
this study to rank low among the import-

ant duck food plants in Illinois, table 37.

Although it occurred sparingly in the areas

from which gizzards were collected in

1938-1940, it produced a moderate
amount of seed (Low & Bellrose 1944:

13). Analyses of gizzard contents showed
that most species of waterfowl fed on the

seeds and tender roots ; however, only the

large ducks were able to use the tubers.

The usefulness of this plant seemed to be

partly dependent upon accessibility—on

water levels sufficiently high to allow the

ducks to feed in the duck-potato beds.

Structures of this plant, found in 167

gizzards, comprised 1.31 per cent of the

Fig. 16.—Sago pondweed {Potamogeton pectinatus) , known also as teal grass and eel grass.
Ducks feed upon its seed, foliage, and tubers.



August, 1959 Anderson: Food Habits of INIigratory Ducks 337

Fig. 17.—Duck-potato [Sagittaria lafifolia),

known also as arrowhead, wapato, or boot-

jack. Ducks value it more for its seed than for

its tubers.

total organic contents of the gizzards col-

lected for examination, table 38. The
plant apparently increased in duck food

value as the fall season waned. In Octo-
ber, it represented less than 1 per cent of

the plant contents of gizzards, but 3 per

cent by December. This plant may be

considered a fair duck food throughout

the fall, increasing in importance as the

season advances.

River-Bulrush
Scirpus fluviatilis

River-bulrush seeds occurred in about

one-tenth of the duck gizzards collected

in 1938-1940 from areas along the Illi-

nois and Mississippi rivers, table 38. The
total quantity of river-bulrush seeds was
only 0.29 per cent of all the organic food.

The number of gizzards in which river-

bulrush seeds were found (510) is con-

sidered large in view of the fact that seed

production of this plant is poor in Illinois

(Bellrose & Anderson 1943:430). Evi-

dently the seeds are very palatable.

Teal Grass
Eragrostis hypnoides

Teal grass was found to be another

moist-soil plant that ranked among the

important sources of duck food in the pe-

riod of this study, table 37. Under cer-

tain conditions, when water levels were
sufficiently high to flood the plants grow-
ing along ditchbanks and mud flats, it

ranked much higher than when conditions

were less favorable. It appeared among
the important native foods because of large

numbers of seeds consumed by a relatively

small number of ducks. The green-winged
teal, blue-winged teal, and pintail fed

more upon this plant than did other spe-

cies of ducks.

Seeds of teal grass, found in 114 giz-

zards, constituted 0.96 per cent of the total

organic contents, table 38. After Novem-
ber 15, utilization of this plant rapidly de-

creased. The drop was due partly to ice

fringes that prevented ducks from having

access to the seeds and partly to a decrease

in numbers of the ducks that were the

principal consumers of these seeds. Teal
grass may be considered a fair source of

earlv-fall food but a poor source of late-

fall" food.

Giant Bur-Reed
Sparganium eurycarpiuii

Giant bur-reed occurred in small beds

scattered among the bottomland lakes of

the Illinois River valley in the years giz-

zards were collected for this study. De-
spite the very limited occurrence of giant

bur-reed, a comparatively large number of

gizzards, 286 from the Illinois River val-

ley and 24 from the Mississippi River val-

ley, contained seeds of this plant, table 38.

The high rate of utilization indicates that

ducks found the nutlike seeds of the giant

bur-reed very palatable, but that the small

quantity available limited the importance

of giant bur-reed, which ranked last

among the 19 most important plants, table

37.

ANIMAL FOODS

This stud}' indicated that animal foods

were not important in the diet of most

species of waterfowl migrating through

Illinois in the autumns of 1938, 1939, and

1940, although impressive numbers of ani-

mal groups were found in the gizzards

collected. The lesser scaup duck, ring-

necked duck, shoveler, blue-winged teal,

and green-winged teal were among the



338 Illinois Natural History Survey Bulletin Vol. 27, Art. 4

Table 39.—The most important animal foods of ducks taken along the Illinois River,

Ottawa to Florence (4,505 gizzards), and along the Mississippi River, Rock Island to Quincy
(472 gizzards), 1938-1940.

.Animal

Illinois River

Occur-
rence

(Number
of Giz-

zards)

Volume
(Cubic
Cenri-

meters)

Per Cent
of

Organic
Contents

Mississippi River

Occur-
rence

(Number
of Giz-

zards)

Volume
(Cubic
Centi-

meters)

Per Cent
of

Organic
Contents

TOTAL ANIMAL.

BRVOZOA, moss animals
MOLLUSCA
Gastropoda, snails

Stagnicola

Planorhis

Uelisonia

Gyraulus
Carinijex

Physa
Viviparus

Campeloma
Lioplax

Amnicola
Flumnicola
Somatogyrns
Pleurocera

Neritina

Unidentified Gastropoda
Pelecypoda, mussels

Sphaeriidae
Pisidium
Musculium
Sphacriutn

Unidentified Sphaeriidae. . .

Unionidae, fresh-water clams. .

Unidentified Pelecypoda
Unidentified Mollusca

ARTHROPODA
Crustacea

Branchiopoda
Copepoda
Ostracoda
Malacostraca

Insecta
Orthoptera
Neuroptera, hellgrammites
Ephemeroptera, mayflies

Hexagenia
Caenis

Odonata
Anisoptera, dragonflies

Zygoptera, damselflies

Unidentified Odonata
Homoptera

Cicadellidae, leafhoppers. . . .

Hemiptera
Corixidae, water boatmen
Notonectidae, backswimmers.
Nepidae, waterscorpions
Belastomatidae, water bugs. .

Gerridae, water striders

Miridae, Lygiis, plant bugs...
Lygaeidae, chinch bugs

136

3

7

1

7

2

26
8

45
4
3

16

2

167

15

20
45
6

9
28
81

3

9

105

27

3

1

80
2

9

17

6

329
2

2

22
2

1

1

941.57

9.97

5.70
1 . 50
1.17
0.58
0.40
3.40
4.90
34.20
3.25

43.15
5.50
0.90
5.50
2.50

143.49

17.70
27.50
94.50
23.30
10.80
17.64
48.94

1.40
4 30
4 20
18.91

0.52
0.50

31.25
0.10

2.80
14.00
3.60

0.20

128.52
0.30
0.80
17.73

20
t

t

5. 18

0.05

03
01

0.01

t

t

0.02
0.03
0.19
0.02
0.24
0.03
t

0.03
0.01

0.79

0.10
0.15
0.52
0.13
0.06
0.10
0.27

0.01
0.02
0.02
0.10

t

t

0.17
t

0.02
0.08
0.02

0.71
t

t

0.10
t

4
1

11

4
9

2

13

29

1

37

143.24

t

0.20
11.80
1.80

13.80
3.10
0.80
0.30

10.78

5 90
2.70

16 20
13.70
4.89
2.80
18.50

2.50

t

13.68

2.10
t

t

4.33

0.12

0.02
0.03



August, 1959 Anderson: Foou Habits of Migratory Ducks 339

Table 39.—Continued.

Illinois River

Animal

Coreidae, squash hugs
Pentatomidae, stink bugs. . . .

Unidentified Hemiptera
Coleoptera

Carabidae, ground beetles. . .

.

Omophron
Haliplidae

Dytiscidae, diving beetles. . .

.

Gyrinidae, whirligig beetles. .

Hydrophilidae, water scaven-

ger beetles

Staphylinidae, rove beetles . .

.

Puprestidae, t!atheaded wood
borers

Drvopidae
Elmidae
Scarabaeidae, scarab beetles..

Chrysomelidae, leaf beetles. .

.

Curculionidae, snout beetles .

I'nidentified Coleoptera
Trichoptera, caddisFies

Hydroptilidae
Hydropsychidae
Unidentified Trichoptera

Lepidoptera
Diptera, flies

Chironomidae, midges
Tabanidae, horse hies

Anthomyiidae
Unidentified Diptera

Hymenoptera
Ichneumonidae, ichneumons. .

Tiphiidae, Tiphia, tiphiid wasp.s

Formicidae, ants. . .

Unidentified Hymenoptera . .

Unidentified Insecta

Arachnida
AcARiNA, water mites

CHORDATA
Pisces, fish

Amphibia, frogs.

UNIDENTIFIED ANIMAL
NONFOOD

Parasitic worms
Feathers

Occur-
rence

(Number
of Giz-

zards)

3

5

46

3

227
8

6

6

1

1

2

6

12

17

6

132
13

19

4

238
2

1

14

3

2

6

1

15

21

75

18

1

83

Volume
(Cubic
Centi-

meters)

0.40
0.57

1.32

0.17
23.97
0.37

0.90
0.29

t

t

t

86

50
2.90
0.55

5.99
11.66
2.25
0.39

127.61
0.50
0.09
5.63

0.05
0.10
0.10
0.96
5.09
0.72
0.37

0.72
1.00
0.80

0.20
8.72

Per Cent
of

(Organic

Contents

01

t

0.13
t

t

t

t

t

0.02
t

0.03
0.06
0.01

t

0.70
t

t

0.03

t

t

t

t

0.03
t

t

t

t

t

t

0.05

Mississippi River

Occur-
rence

(Number
of Giz-

zards)

Volume
(Cubic
Centi-

meters!

0.12

0.12
20

0.35
0.10

6.00

0.27

0.20

09

4.70

0.20
0.10

0.08

0.14

0.52

Per Cent
of

Organic
Contents

0.01

0.01
0.01

0.02
0.01

40

0.02

0.01

0.01

0.32

0.01
0.01

0.01

0.03

species that were the principal consumers

of animal foods.

Animal parts constituted 5.52 per cent

of the organic contents of all waterfowl
gizzards collected in the years of the study.

The two outstanding animal groups were

mollusks and insects, table 39. The for-

mer comprised 55.66 per cent of the total

animal foods and the latter 39.32 per cent.

Crustaceans comprised 2.89 per cent of

the animal foods.

Mollusca

Snails comprised 49.47 per cent of the

Mollusca and 27.54 per cent of the ani-

mal foods, while mussels constituted 39.36



340 Illinois Natural History Survey Hulletin Vol. 27. Art. 4

per cent of the Alollusca and 21.90 per

cent of the animal foods, table 39.

fresh-water snails found in the largest

numbers of duck gizzards were Amtiicola,

Canipelonia, and Pleuroccra. Fragments

of a brackish water snail, i^eritina, were

found in two gizzards. 'Ihe mussels iden-

tified were of no commercial use; most of

them were small and thin shelled. Genera

represented included Sphaeriuin, Pisidiuni,

and Musct/liurn.

Insecta

The insects represented 2.17 per cent of

the total organic foods and 39.32 per cent

of the total animal foods in the gizzards

examined, table 39. Man.v species of in-

sects were represented in gizzards collected

prior to November 15, but after this date

the volume and the number of species of

insects decreased. This decrease was due

in part to a decline in the populations of

ducks that feed upon insects and in part to

a decline in the number of insects avail-

able.

Among the insect material found in

greatest volume in the duck gizzards were

Odonata nymphs, midge larvae, mayfly

nymphs, fig. 18, caddisfly larvae, and

water boatmen.

Crustacea

In the duck gizzards collected, Crus-

tacea constituted only a small portion of

the animal foods, table 39 ; in greatest

volume were the crayfish (Malacostraca).

The minute forms appeared in many giz-

zards but in negligible volumes; among
them were water fleas (Branchiopoda),

amphipods and pillbugs (Malacostraca),

and ostracods.

Bryozoa

These small animal forms appeared

most often as traces in the duck gizzards

collected. The winter buds or statoblasts

of Pectinatella and Plumatella probably

had been eaten along with other foods.

Amphibia

Frog bones appeared in only one giz-

ird

Arachnida

A few spiders and water mites were
found in the contents of the gizzards col-

Fig. 18.—Mayfly nymph of the genus Hcxa-
gcnia. This is one of the animal foods con-
sumed by ducks that migrate through Illinois

in autumn.

lected ; they were not considered important

waterfowl foods.

Pisces

Fish vertebrae and scales were occasion-

ally found in the duck gizzards collected.

Mallards and black ducks have been

known to feed extensively on gizzard

shad, Dorosoma cepedianufti.

GRIT

Generally grit is considered to have two
functions in avian nutrition: (1) assisting

the gizzard in the grinding of food and

(2) furnishing necessary minerals for me-

tabolism and reproduction (Nestler 1946:

137). Because grit invariably appeared in

the gizzards examined in the present study,

it seems reasonable to conclude that ade-

quate supplies of hard, nonfriable particles

were available to waterfowl in the Missis-

sippi Flyway. Experiments with captive

wild mallards have shown, moreover, that

the grit demands of waterfowl may be low
even in areas of grit abundance. When
supplied with granite grit, each of 30 mal-

lards under observation at the Havana lab-

oratory of the Illinois Natural History

Survey took an average of slightly less

than one piece per day for a period of 141/2



August, 19S9

Table 40.

Anderson: Food Habits of Migratory Ducks

-Grit contents of duck gizzards collected in Illinois, 1938—1940.

341

Species



.U2 Iluinois Natural History Survey Bulletin Vol. 27, Art. 4

measured in millimeters across the widest

dimension regardless ot ti.e shape. '1 hese

varied from minute to 19 mm. in size;

most of them were under 2 mm. Grit m
mallard, pintail, ring-necked duck, and

lesser scaup gizzards consisted mostly ot

stones over j mm. in size, lialdpate and

gadwall gizzards seluom contained gritty

material larger than sand particles. Teal

and shoveler gizzards seldom contained

stones over 2 mm.
The frequency with which sand oc-

curred to the exclusion of stones in the

haldpate and gadwall gizzards suggests a

relationship between the food habits and

physical composition of the grit ingested

by these species. Baldpates and gadwalls

generally feed on soft, leafy aquatic plants,

which are likely to require little or no

grinding during the digestive processes,

and the sand recovered from the gizzards

of these ducks may have been taken only
because it adhered to the food ; or it may
have been unintentionally taken during
normal feeding activity.

Shell fragments, rather than stones,

were found in the gizzards of many lesser

scaups, ring-necked ducks, redheads, gold-

eneyes, and shovelers. Many other par-

ticles classified as inorganic material were
found in the gizzards examined. Fossil

fragments of crinoid stems, wood, coral,

and brachiopod shells were not uncommon.
Muskrat and fish teeth were numerous.

Most of these items were rough and angu-

lar, serving as excellent grinding agents.

LEAD SHOT

Lead shot pellets were found in the giz-

zards of most of the species of ducks in-

cluded in this study, table 41. Some of

Table 42.—The number of duck gizzards collected in Illinois in each of 3 years, the num-
ber and percentage of these that contained lead shot pellets, and the number of pellets per giz-

zard among the gizzards that contained lead.

Year



August, 1959 Anderson: r\)OD Habits of Migratory Ducks 343

these pellets had been ingested by ducks in

their feeding and some had become lodged

in the gizzards at the time the birds were
killed.

The lining of many gizzards containing

lead shot was dark green in color. Any
duck from which a gizzard of this color

had been taken was considered to have

been sick before it was shot.

Water levels and firmness of lake or

marsh bottoms are among the factors that

determine the accessibility and availability

of lead shot to waterfowl (Bellrose 1959:

249). Although the percentage of giz-

zards containing lead pellets did not vary

greatly from year to year for the 3-year

period of the study, the average number
of pellets per gizzard changed materially,

table 42.

Probably the lead shot was consumed in

the season it was deposited rather than in

a subsequent season (Bellrose 1959:266).

The gizzard contents showed an increase

in percentage of gizzards with lead shot as

well as an increase in the number of pel-

lets per gizzard as the autumn progressed,

table 43.

SUMMARY

1. In the autumns of 1938, 1939, and

1940, duck gizzards totaling 4,977 were
collected from hunting clubs and indi-

vidual hunters at 21 sites along the Illi-

nois River between Ottawa and Florence

and 11 sites along the Mississippi River

between Rock Island and Quincy. The
following 17 duck species were repre-

sented : mallard, pintail, green-winged

teal, blue-winged teal, baldpate, gadwall,

shoveler, black duck, wood duck, lesser

scaup, ring-necked duck, redhead, canvas-

back, ruddy duck, greater scaup, common
goldeneye, and oldsquaw.

2. Analyses of the gizzard contents

were made in accordance with the proce-

dure instituted and followed by the U. S.

Fish and Wildlife Service, Department of

the Interior.

3. The analyses indicated tliat, during
the fall, most species of ducks in Illinois

are predominantly vegetarians, that most
of them feed principally on native wild
plants, and that the lesser scaup is the only

species with a diet predominantly animal.

4. Corn made up nearly half of the or-

ganic contents of mallard gizzards. Na-
tive wild foods were present in relatively

greater quantities in gizzards of the wood
duck, pintail, redhead, baldpate, green-

winged teal, and ring-necked duck, all of

which included corn in their diets.

5. Of the 95 wild plants and 4 cul-

tivated plants found in the gizzards and
identified to species, the following 19 were
most important: corn, rice cutgrass, marsh
smartweed, coontail, wild millet, longleaf

pondweed, red-rooted nut-grass, water-
hemp, nodding smartweed, buttonbush,

large-seeded smartweed, nut-grass, chufa,

Walter's millet, sago pondweed, duck-

potato, river-bulrush, teal grass, and giant

bur-reed.

6. The relative positions of the impor-

tant food plants changed from year to year

as accessibility and availability varied.

7. The importance of a plant species

to a species of duck depended on the size

of the duck and the type of feeding habitat

frequented by the duck.

8. The dabbling ducks fed primarily on
emergent and moist-soil plants and the div-

ing ducks more frequently on submergent
plants. Animal foods were more important

to diving ducks than to dabbling ducks.

9. Snails and mussels provided the

largest animal food volume and occurred

in the largest number of gizzards. Insects

were second in volume and occurrence.

10. Grit constituted about 11 to 28 per

cent of the gross contents of the gizzards

of various duck species. Most of the stones

were less than 2 mm. in size ; the sizes

ranged from minute to 19 mm. in size

(largest dimension).

11. More than 200 of the gizzards ex-

amined contained lead shot pellets that

had been ingested.



LITERATURE CITED

Bellrose, Frank C.
1938. Abundance and food habits of the waterfowl in the Illinois River valley. Bachelor's

thesis, University of Illinois, Urbana. 33 pp.

1941. Duck food plants of the Illinois River valley. 111. Nat. Hist. Surv. Bui. 21 (8) :237-80.

1959. Lead poisoning as a mortality factor in waterfowl populations. 111. Nat. Hist. Surv.
Bui. 27(3):235-88.

Bellrose, Frank C, and Harry G. Anderson
1940. Preliminary report on availability and use of waterfowl food plants in the Illinois

River valley. 111. Nat. Hist. Surv. Biol. Notes 15. 14 pp. Mimeo.
1943. Preferential rating of duck food plants. 111. Nat. Hist. Surv. Bui. 22(5) :417-33.

Cottam, Clarence
1936. Economic ornithology and the correlation of laboratory and field methods. U. S.

Biol. Surv. Wildlife Leaflet BS-.^O. 13 pp. Mimeo.

Gerstell, Richard
1942. The place of winter feeding in practical wildlife management. Pa. Game Comn. Res.,

Bui. 3. 121 pp.

Fernald, Merritt Lyndon
1950. Gray's manual of botany. Ed. 8. American Book Company, New York. 1,632 pp.

Hawkins, Arthur S., and Frank C. Bellrose

1939. The duck flight and kill along the Illinois River during the fall of 1938. Am. Wild-
life 28(4): 178-86.

Hawkins, Arthur S., Frank C. Bellrose, Jr., and Harry G. Anderson
1939. The waterfowl research program in Illinois. 111. Nat. Hist. Surv. Biol. Notes 12.

16 pp. Mimeo.

Low, Jessop B., and Frank C. Bellrose, Jr.

1944. The seed and vegetative yield of waterfowl food plants in the Illinois River valley.

Jour. Wildlife Mgt. 8(l):7-22.

Martin, A. C., and F. M. Uhler
1939. Food of game ducks in the United States and Canada. U. S. Dept. Ag. Tech. Bul^

634. 156 pp.

Nestler, Ralph B.

1946. Mechanical value of grit for bobwhite quail. Jour. Wildlife Mgt. 10(2) : 137-42.

Wetmore, Alexander
1919. Lead poisoning in waterfowl. U. S. Dept. Ag. Bui. 793. 12 pp.

L3441





Some Publications of the Ilunois Natural History Survey

BULLETIN
Volume 26, Article 3.—Natural Availability

of Oak W^ilt Inocula. By E. A. Curl. June,

1955. 48 pp., frontis., 22 figs., bibliog.

Volume 26, Article 4.—Efficiency and Selec-

tivity of Commercial Fishing Devices Used

on the Mississippi River. By William C.

Starrett and Paul G. Barnickol. Jqly,

1955. 42 pp., frontis., 17 figs., bibliog.

Volume 26, Article 5.—Hill Prairies of Illi-

nois. By Robert A. Evers. August, 1955.

80 pp., frontis., 28 figs., bibliog.

Volume 26, Article 6.—Fusarium Disease of

Gladiolus: Its Causal Agent. By Junius L.

Forsberg. September, 1955. 57 pp., frontis.,

22 figs., bibliog.

Volume 27, Article 1.—Ecological Life History

of the Warmouth. By R. Weldon Larimore.

August, 1957. 84 pp., color frontis., 27 figs.,

bibliog.

Volume 27, Article 2.—A Century of Biological

Research, By Harlow B. Mills, George C.

Decker, Herbert H. Ross, J. Cedric Carter,

George W. Bennett, Thomas G. Scott, James
S. Ayars, Ruth R. Warrick, and Bessie B.

East. December, 1958. 150 pp., 2 frontis.,

illus., bibliog. $1.00.

Volume 27, Article 3.—Lead Poisoning as a

Mortality Factor in Waterfowl Populations.

By Frank C. Bellrose. May, 1959. 54 pp.,

frontis., 9 figs., bibliog. 50 cents, beginning

September.

CIRCULAR
32.—Pleasure With Plants. By L. R. Tehon.

July, 1958. (Fifth printing, with revisions.)

32 pp., frontis., 8 figs.

42.—Bird Dogs in Sport and Conservation.

By Ralph E. Yeatter. December, 1948. 64

pp., frontis., 40 figs.

45.—Housing for Wood Ducks. By Frank C.

Bellrose. February, 1955. (Second print-

ing, with revisions.) 47 pp., illus., bibliog.

46.—Illinois Trees: Their Diseases. By J.

Cedric Carter. August, 1955. 99 pp.,

frontis., 93 figs. Single copies free to Illi-

nois residents ; 25 cents to others.

47.—Illinois Trees and Shrubs: Their Insect

Enemies. By L. L. English. May, 1958. 92

pp., frontis., 59 figs., index. Single copies

free to Illinois residents; 25 cents to others.

BIOLOGICAL NOTES
29.—An Inventory of the Fishes of Jordai

Creek, Vermilion County, Illinois. By
Weldon Larimore, Quentin H. Pickerinf

and Leonard Durham. August, 1952. 2i

pp., 25 figs., bibliog.

30.—Sport Fishing at Lake Chautauqua, neat

Havana, Illinois, in 1950 and 1951. B]p

William C. Starrett and Perl L. McNeil,|

Jr. August, 1952. 31 pp., 22 figs., bibliog.

31.—Some Conservation Problems of the

Great Lakes. By Harlow B. Mills. Octo-

ber, 1953. (Second printing.) 14 pp., illus.,

bibliog.

33.—A New Technique in Control of the

House Fly. By Willis N. Bruce. Decem-
ber, 1953. 8 pp., 5 figs.

34.—White-Tailed Deer Populations in Illi-

nois. By Lysle R. Pietsch. June, 1954. 24

pp., 17 figs., bibliog.

35.—An Evaluation of the Red Fox. By
Thomas G. Scott. July, 1955. (Second

printing.) 16 pp., illus., bibliog.

36.—A Spectacular Waterfowl Migration

Through Central North America. By Frank

C. Bellrose. April, 1957. 24 pp., 9 figs.,

bibliog.

37.—Continuous Mass Rearing of the Euro-

pean Corn Borer in the Laboratory. By
Paul Surany. May, 1957. 12 pp., 7 figs.,

bibliog.

38.—Ectoparasites of the Cottontail Rabbit in

Lee County, Northern Illinois. By Lewis J.

Stannard, Jr., and Lysle R. Pietsch. June,

1958. 20 pp., 14 figs., bibliog.

39.—A Guide to Aging of Pheasant Embryos.

By Ronald F. Labisky and James F. Opsahl.

September, 1958. 4 pp., illus., bibliog.

40.—Night-Lighting: A Technique for Cap-

turing Birds and Mammals. By Ronald F.

Labisky. July, 1959. 12 pp., 8 figs., bibliog.

MANUAL
3.—Fieldbook of Native Illinois Shrubs. By
Leo R. Tehon. December, 1942. 307 pp.,

4 color pis., 72 figs., glossary, index. $1.75.

4.—Fieldbook of Illinois Mammals. By Donald

F. Hoffmeister and Carl O. Mohr. June,

1957. 233 pp., color frontis., 119 figs., glos-

sary, bibliog., index. $1.75.

List of available publications mailed on request.

Single copies of Illinois Natural History Survey publications for which no price is listed

will be furnished free of charge to individuals until the supply becomes low, after which a

nominal charge may be made. More than one copy of any free publication may be obtained

without cost by educational institutions and official organizations within the State of Illinois;

prices to others on quantity orders of these publications will be quoted upon request

Address orders and correspondence to the Chief, Illinois Natural
History Survey, Natural Resources Building, Urbana, Illinois

Payment in the form of money order or check made out to State Treasurer of Illinois,

Springfield, Illinois, must accompany requests for those publications on which a price is set.