Bull1Iss6ArtI


THE REGULATIVE ACTION OF BIRDS UPON INSECT 

ORCILLATI O NS. 

BY . A. FORBES. 

Attention has already been repeatedly called in these studies to 
the fact (fundamental to this investigation) that the principal inju­
ries due to insects are done by a few species, existing, for a time, in 
numbers far above the average, and soon to retire again to a much 
lower limit. As the number of a species which reach maturity is 
determined by the checks on its multiplication, it follows that these 
oscillating species are held in check by variable forces, and to the 
variations in these checks we must look for an explanation of 
their oscillations. On the other hand, we must expect to find 
that those insects whose numbers remain relatively constant from 
year to year are under the control of restraining influences of a 
much more uniform character than the preceding class. 

Concerning the effects of birds upon insect life, and through 
this upon the interests of agriculture, there are therefore three 
questions to answer:-

1. Do birds originate any oscillatiolls among the species of 
insects upon which they feed ? That is, are their food habits ever 
so inconstant from year to year that species which are at one time 
principal elements of thf\ir food, are at other times neglected and 
allowed to n:iultiply without restraint ? 

2. Do birds prevent or restrain any oscillations of insects now 
noxiou , or capable of becoming so if permitted to increase more 
freely ? That is, do they bring to bear upon any such species a 
constant pressure so great that those insects would increase 
unduly if this pressure were removed by the destruction of the 
birds? 

3. Do they do anything to reduce existing oscillations of inju­
rious insects ? Do they sometimes vary their food habits so far 
as to neglect their more usual food and take extraordinary nu:r:ibers 



4 The R egulative Action of Birds upon Insect Oscillations. 

of those species which, for any reason, became superabundant for a 
time? 

For the purpose of answering these questions, two separate 
lines of investigation are necessary. For the first two we require 
a knowledge of the food habits of the various species of birds 
·under ordinary circumstances, when the conditions of life are of 
average char:acter, and especially when no species of insects are 
unusually and excessively abundant. On the other hand, for an 
answer to the third question we must look to the food habits of the 
birds under extraordinary circumstances, where the opposite 
condition of affairs prevails. We must learn to what extent birds 
depart from their usual practices when confronted by an uprising 
of some insect species. If they concentrate for its suppression, 
they must assist more or less effectively to reduce ·to order the 
disturbed balance of life; but if they remain indifferent to this 
condition of things, their influence is nil. 

The present paper is a contribution to a discussion of the last 
of the above questions. As a striking and .conclusive example of 
an extraordinary condition of insect life, and of the food of birds 
in the presence of a disturbed balance of nature, I selected an 
orchard which had been for some years badly infested by canker ­
worms, shot a considerable number of birds therein for two suc­
cessive years, representing nearly all the kinds seen in the orchard, 
made full notes of the relat~ve abundance of the species, exam­
ined carefully the contents of all the stomachs obtained, with 
reference not only to the presence of canker-worms but of all 
other insects as well, and tabulated the results as the basis of this 
paper. Besides preparing as full an account of the food of these 
birds as practicable, I have brought the summaries on these tables 
into comparison with those derived from birds of the same species 
shot in ordinary situations during the same month. These com­
parisons have been confined to a few of the kinds obtained in 
the orchard, for the reason that most were not found there in suf­
ficient number to give a fair idea of the average food of the 
species. The collections were made in an orchard of forty-five 
acres of bearing apple-trees ( belonging to Mr. J. W. Robison) 
in Tazewell County, Ill., which had been infested by canker-worms 
for about six years. As a result of their depredations, a consider­
able part of the orchard had the appearance, from a little distance, 



The Regulative .Action of Birds upon Insect Osr::illations. 5 

of having been ruined by :fire. Closer examination of the trees 
most aff cted showed that the branches, stripped of every vestige 
of green, were festooned with th webbing left by the worms. 
To the w bs the withered remnants of the leaves adhered as they 
fell, the very petioles having b en gnawed off at the twigs. Not 
one per ent. of the trees w re uninjured, and th se were invaria­
bly on the outer part f the orchard. Tho e which had been 
attack d several y ars in ·ucL:e sion were killed; and there was a 
large area in the midst of the orchard from which such trees had 
been removed. One did not need to enter the enclosur to learn 
that the birds were pr ent in extraordinary numbers and variety. 
Fr m every part of it arose a chorus of song more varied than I had 
ever beard in any similar area at that season of the year. Most of 
the common summer resid nts were found there; and upon a second 
visit in 1882 many of the migrant specie likewise occurred. The 
:first collection was made on th 24th of May, 1881, and the 
second on the 20th of the same month im the following year. 
The season was less advanced at the time of the second collection 
than at the first, so that the actual difference between the two was 
probably not less than two weeks. At the first visit fifty-four 
birds were taken, representing twenty-four species, and seven other 
pecies were noted in the orchard of which no pe imens were 

obtained. On the second visit n · nety-two birds were shot, repr -
senting thirty-one species, and four other speci s were seen. In 
1881 the worms were nearly all fully grown, and many of them 
bad already entered the ground for their transformation, so that 
the larvre were less abundant than they had b en earlier. In 1882 
most of them were about half-grown, only a few having reached 
adult size. They were distinguishable with difficulty upon the 
leaves of the trees; but when a large branch was shaken or jarred, 
from a dozen to twenty would expose themselves by spinning 
down and hanging at the e_ d of a thread. The owner of the 
orchard informed me that they were about twice as abundant the 
preceding season. 

TURDIDJE. Thrush s. 

TuRnus i'!IIGRATORIU , L. Rom 

This speci s was abundant and nesting in the orchard. Nine 
specimens were obtained in all, three in 1881 and six in the fol-



6 The Regulative Action of Birds upon Insect O cillations. 

lowing year. The food was wholly animal, neither fruit nor any 
other kind of vegetation having been taken by any of the birds. 
Only three of the above number had eaten canker-worms, which 
composed, as nearly as could be estimated, about one-fifth of the 
food of the entire group. Insects made ninety-three per 
cent., the remainder consisting of a common species of my­
riapod (five per cent.), earth-worms, and gasteropod mol­
lusks. Ants were eaten by these birds only in trivial 
numbers. Diptera, Orthoptera and spiders were conspicuous 
by their entire absence. Cut-worms were extraordinarily 
prominen~ in the food, making twenty-eight per cent. of the 
whole. Half of them consisted of a single large, injurious 
species (Nephelodes violans). Among the Coleoptera, which 
amounted to thirty-six per cent. of the whole, the Scarabreidre 
and Elateridre were the principal elements, the former represented 
by eighteen per cent., and the latter by eleven. Among the Scar­
abreidre was a species known as a vine leaf-chafer (Anomala 
b'inotata), which made fourteen per cent. of the food. This in­
sect was scarcely less abundant than the canker-worm, and 
appeared in extraordinary numbers in the food of nearly all the 
species of birds examined, althc;mgh it had not attracted the atten­
tion of the owner of the grounds. I searched a small vineyard ad­
jacent, but saw no signs of unusual injury to the leaves. Carabidre, 
although common in the orchard, had scarcely been touched by 
the robins, only a single specimen of the family occurring. 
Hemiptera were found but in trivial numbers, representing about 
equally the families Coreidre and Cydnidre. Hymenoptera were 
still less abundant, composing only one per cent. of the food. 

MrMus CAROLINENSIS, L. C ATBIRD. 

This species was very common, and thoroughly at home among 
the trees, where it was doubtless nesting. Fourteen specimens 
were taken, three at the first visit and eleven at the second. 
With the exception of two per cent. of myriapods, their food con­
sisted entirely of insects. ~anker-worms had been eaten by eight 
of the birds, but not in any great number, as they composed but fif­
teen per cent. of the food of the species. A few cut-worms had 
been taken, and a larger number of other caterpillars, bringing 
the total for Lepidoptera up to about one-fourth of the food. 



The Regulatii-e Action of Bird upon Jn ect Os~illations. 7 

The catbird had hown it u ual preferenc for ants, eating f ur­
te n per c nt. of the e in ects. The e bird had taken an unusual 
numb r of ole ptera which made m r than half th food, 
hi fl carab, i 1 . b ut two-third of them b 1 nged to th 
inale pe (~lnonwla binotata) m ntioned abo under the 

£ od of th robin. Thr e f the e bird had lik wise aten large 
June bu Elaterid and their larvre occurred only in tri ial 
quantiti while arabiclre amounted to four per cent., chiefly 

ni odact lu . in tb robin, Diptera, rthoptera, and Arach-
nida, were not repre · nted in the food. 

filRPORHYX HU RUF ~ L. BROWN THR SH. 

This bird wa not c mmon in the orchard, and only four pe i­
men were taken. The food of these was entirel animal, an 
unexpected ircum tanc as the brown thrush usually feeds 
lar ely upon ram. ix per cent. of the fo d on isted of 
thou and-leg , ancl in ect · made the entire remainder. Lepidop­
tera were abou one-fifth of the food, and half of these were 
cank r-worm . Like the precedmg speci s, this bird had eaten 
an enormou number of beetles, which amounted to two-thirds of 
it food . Twelve per cent. of the whole was Carabidre, chiefly a 
species of hlreniu . carabreid tand at forty-four per cent., 
lar ely Diplota:s:.i Mel lontba, and Anomala. ix per cent. were 
Elateridre and three per ent. Rh nchophora. o specimens of 
the remaining order had been eaten by the e birds. 

S u m m a 1· y of t h Family. 

Treatino- now of the twenty-seven thru he mentioned as one 
roup we find that none of them had eaten any egetation what­

ever; that ninet - ix per cent. of their food con isted of inse ts 
(myriapods and earth-worm making up the remaining four per 
cent.) · that ix.teen per c nt. was canker-worms; and only four 
per cent. predac u be tle ·. The Anomala previously men­
tioned mad just a fourth f th ir entire food, other carabreidre 
bringino- up the av ra f that family to thirty-eight per cent. 

li k b etle (Elatericl.re) with their larv, w re five per cent. of 
the whole, and nout be tl (Rhynchophora) tw per cent. 



8 The Regulative Action of Birds upon Insect Oscillations. 

SAXICOLID.iE. Bluebirds. 

SIALIA SIALIS, L. BLUEBIRD. 

This species was not at all abundant in the orchard in either 
year. Only one was taken in 1881, and four in 1882. A ll but 
two per cent. of the food of these five specimens consisted of 
insects, spiders makjng the remainder. Canker-worms were 
twelve per cent. of the food, and other L epidoptera five per cent. 
additional. Two-thirds of the food consisted of Coleoptera. 
Carabidre made more than one-third (twenty-three per cent.), 
belonging chiefly to a species (Anisoclactylus baltimorensis) 
which depends largely upon vegetable food. Four of the 
birds had eaten Anomala binotata, which made thirty-six per 
cent . of the food of the whole. Five per cent. was Chrysomelidre, 
and fifteen per cent. Hemiptera, all belonging to the family 
Cydnidre. 

P ARID.iE. Chickadees. 

PARUS A.TRICAPILLUS, L. BLACK-CAPPED CHICKADEE. 

This little bird, unfortunately, was not at all common in the 
orchard; and only two specimens were taken, one in each year. 
Sixty-one per cent. of their food consisted of canker-worms, eaten 
by both the birds, and Coleoptera made the entire remainder. 
These were nearly all Cerambycidre (Psenoce'i·us supernotatus) 
and Rhynchophora of undetermined species, twenty-five per cent. 
of the former, and ten of the latter. 

TROGLODYTID.iE. Wrens. 

TROGLODYTES DOMESTICUS, Bartr. HOUSE WREN. 

Several specimens of this little species were observed, some of 
them evidently nesting. The food was chiefly insects,-all, in 
fact, but six per cent. of spiders and one of thousand-legs. 
Nearly half the food of these birds consisted of canker-worms, 
and other Lepidoptera and their larvre brought the average of the 
order up to fifty-nine per cent. A few gnats and other Diptera 
(four per cent.) and five per cent. of ants were also noted. Cole- ·. 
optera and H emiptera were taken in nearly equal quantities, t hir ­
teen per cent. of the former and ten of the latter. Two of the 



The Regulati1.'e Action of Birds upon Insect Oscillations. 

birds had eaten P enoc ,·u ,- , l{pernotat'll , _ amounting t four p r 
cent. of the food, and the other oleoptera were scattered through 
the familie arabidre, itiduli<lm, Scarabreidre, Elateridm and 

alandridm. The Hemipt ra were repre ented_,by trivial numb rs 
of four familie , includin

0 
a f w chinch bugs. 

IN I TILTID~. Warblers. 

lliL::UINTIIOPHAGA PEREGRL A, Wils. TEN ... ""E EE WARBLER. 

A single pecimen of tbi little warbl r was taken in 1882. 
Four-fifth of its food con isted of canker-worms, and all the 
remainder of a ingle pecies of beetle (T, l •,phonts bilineatus). 

DENDR<ECA £ TIVA Gmel. U:;\I IER YELLOW BIRD. 

This bird common every where at this eason, wa al o abund­
ant in the orchard. Five sp imens w re shot in all. The food 
was in e ts, excepting ix per ent. of spiders. Two-thirds of 
the total amount eaten by all of the birds consist d of canker­
worms. Coleoptera were tw nty-three per cent. of the whole 
amount six p r cent. being Aphodiu , and twelv per c nt . 
Psenoc m · upernotutus; already frequent! mentioned. arab ­
idre and Calandridre were r pres nted by in io-ni:ficant ratios, and 
Lamp ridre by a single T lephoru aten by one of the birds. 
One per cent. of H emiptera, and two of Hymeuoptera complete 
the record. 

DENDR<ECA PENN YLT".A I A, L. 'CHESTNUT- IDED vVARBLER. 

T wo specimens of thi abundant migrant were hot in the 
orchard in 1 2. Like th preceding warbler, two-thirds of th ir 
food con i ted of cank r-worm , and an additional ten per cent. 
of other caterpillars. A few ant were eaten by both of the birds. 
Eleven p r cent. f ol optera, likewi e eaten by the two, was 
about equally divided betwe n ome undetermined Scarabreidre 
and P senocerus supeniotcttu . One of th birds had eaten plant­
lice, which amounted to :fi.v per cent. of the food; and both had 
taken ants to the amount of six per cent. 

DENDR<ECA TRI.A.TA, Forst. BLACK-POLL WARBLER. 

F our of these bird were shot in 1882. Some undetermined 
seeds found in the crop of one of them reduced the in ect rati 



i O 1'he Regulative A ction of Birds upon Insect Oscillations. 

to ninety-five. Again two-thirds of the food consisted of canker­
worms. The same little borer (Psenoce1··us) eaten by so many of 
the smaller birds in this orchard, made :fifteen per cent. of the 
food; and an Aphodius and an undetermined carabid bring up 
the ratio of the Coleoptera to nineteen per cent. Four per cent. 
of ants, a few gnats (five per cent.), and traces of Hemiptera and 
mites were the only other elements detected. 

DENDR<ECA VIRENS, Gm. BLACK-THROATED GREEN WARBLER. 

A single specimen of this migrant was shot in 1882. Seventy 
per cent. of its food consisted of canker-worms, :fifteen per cent. 
of Psenocerus, and :five of undetermined Hemiptera. The remain­
ing ten per cent. was made up of trivial numbers of Hymenop­
tera, gnats, coleopterous larvre and mites. 

GEOTHLYPIS TRICHAS, L. MARYLAND YELLOW-THROAT. 

This resident warbler occurred but sparingly in the orchard. 
One specimen was seen in 1881, and two were obtained in 1882. 
Lepidoptera made four-fifths of their food, about equally canker­
worms and undet ermined caterpillars. A few Staphylinidre and 
some specimens of Psenocerus composed the eight per cent. of 
Coleoptera. A small hemipter (Piesma cine1·ea) amounted to :five 
per cent., and four per cent. was gnats. 

Summary of the F a mily. 

Of the warbler family as a whole, as represented by these 
fifteen specimens, I need only remark that fourteen of the birds 
had eaten canker-worms, which composed nearly or quite two­
thirds of the food of the group; that ten per cent. consisted of 
Psenocerus supernotatusj and that the remaining averages, with 
the exception of six per cent. of undetermined caterpillars, were 
so much subdivided as to have little or no significance. 

VIREONID.tE. Vireos. 

VIREO GILVUS, V. WARBLING VIREO. 

Three specimens of this little bird were shot, of purely insect­
i vrous habit. They had eaten canker-worms to the amount of 
forty-four per cent.; and other oaterpillars made thirty-five per 



The Begul,ative Action of Birds upon Insect Oscillations. 11 

nt. adcliti nal. f w ol optera (fifte n per cent.) of whjch 
one-thia1- w re carabid lan re, and tbre per c nt. of Cydnjdre 
(Podht::;) were the only other imp rtant lements. 1nornala 
binotata (eight per cent.) T leph ru , and an undetermined lonw 
horn were the other Coleoptera. 

A iPELID.LE. Wax-wings. 

A~IPELI CEDRORUM, V. CEDAR WAX-WING. 

A flock of about thirty of these birds was repeatedly started 
in the orchard during the fir t visit, but none were seen in 1882. 

e,en of the flock were shot, and the content of their stomachs 
carefully tudied. With the exception of a few Aphodii eaten 
by three of the birds in numbers too insignificant to figure in the 
ratio the entire food of all th se birds consisted of canker-worms, 
whi h therefore stand at an average of one hunclred per cent. The 
num her in each stomach, determined by actual count, ranged from 
seventy to one hundred and one, and was usually nearly a hun­
dred. A suming that the e constituted a whole days food, the 
thirty birds were destroying three thousand worms a day, or 
ninety thousand for the month during which the caterpillar is 
exposed. 

HIRD DI I D.LE. Swallows. 

PETRO RELIDOX LU.i: !FRON , Say. CLIFF SWALLOW. 

This specie was nesting in great numbers under the eaves of a 
barn at the edge of the orchard, and many of the birds were 
continually circling through the air. A single specimen was shot, 
and found to contain nothing but the very abundant scavenger 
beetle (Aphoclius inquinatu ), with about two per cent. of unde­
termined Hemiptera. 

FRINGILLID.LE. Finches. 

A TRAGA.LIN ' TRI TI , L. AMERICAN G OLDFINCH. 

A flock of these birds pa sed through the orchard, but only a 
single one was shot. o canker-worms had been eaten by it ; 
but about seventy per cent. of its food consisted of undetermined 
seeds, and the remainder of a harpalid beetle. 

2 



12 The E egulat{ve A r.tion of Birds upon insect Osciltat{ons. 

CoTURNICULus PASSERINus, Wils. YELLOW-WINGED SPARROW. 

A single specimen of this bird, shot in 1881, containe~piders 
thirty per cent., seeds of pigeon grass (Setar-ia) fifteen per cent., 
an unrecognized beetle five per cent., and some undetermined 
caterpillars, certainly not canker-worms. 

SPIZELLA DOMESTIC.A., Bart. CHIPPING SPARROW. 

This species was not common in the orchard in 1881, and only 
a single specimen was obtained; but in the following year it was 
found much more abundant, and seven a<lditional were taken. 
About one-third of the food consisted of caterpillars, half of 
which were recognizable as canker-worms. A large number of 
gnats (twenty-eight per cent.), nearly as many Coleoptera, (prin­
cipally Scarabreidre, including nine per cent. of Anomala), and six 
per cent. of Hemiptera, are all the other noteworthy items. 

SPIZELL.A AG RESTIS, Bart. FIELD SP ARROW. 

This species was less abundant than the preceding, and was 
represented by only three specimens. With the exception of five 
per cent. of gnats, and one of H emiptera, the food of this bird 
was equally divided between L epidoptera and Coleoptera. 
N early half the former ~onsisted of canker-worms, while the 
Coleoptera were represented by Histeridre, Scarabreidre ( chiefly 
the scavengers), Monocrepidius and Rhynchophora. 

SPIZ.A. AMERICAN A, Gmel. BLACK-THRO.A.TED BUNTING. 

This bird was the most abundant species in 1881, though but 
few were seen during the following May. Eleven were shot at 
the first visit and three at the second. With the exception of a 
little wheat eaten by two of the birds, and a trace of undeter­
mined seeds, the food consisted almost entirely of insects an·d mol­

lusks, eighty-eight per cent. of the former and six of the latter 
(Helix). T en of these birds had eaten canker-worms, which 
made forty-thre_e per cent. of the food of the entire group; Lepi­
doptera as a whole composing two-thirds of the food. Among 
the twenty-two per cent. of Coleoptera, we note Harpalus and 
Histeridre, each four per cent., Aphodius and Anomala likewise 
each four per cent., and Sphenophorus and other Rhynchophora, 
two per cent. 



The Regulative Action of Bird.s upon Insect O cillations. 13 

ZAMELODIA LUDOVICI.A.NA, L. Ro E-BREA TED GROSBEAK. 

Only two were seen, and both were killed. A very few canker­
worms were found (five per cent.) with fifty-eight per cent. of 
other cat rpillars. About half the fifteen per cent. of Coleoptera 
were Rhyn hophora, the remainder being Anomala bi1iotata, one 
of the Lampyridre, and undetermined specimens. One-fifth of 
the food consisted of seeds not recognized. 

P.A.SSERINA CY.A.NE.A., L. INDIGO BIRD. 

This bird, noted as common in 1881, was by far the most abun­
dant species in the orchard at the second visit. Eighteen speci­
mens were shot, two in the first and the remainder in the second 
year. Although this bird is one of the typical :finches, only three 
per cent. of its food consisted of seeds, chiefly Setaria and Com­
positre. Canker-worms made :fifty-nine per cent., eaten by all the 
birds but one, and other caterpillars an additional eight per cent. 
With the exception of a trace of Hymenoptera, the remainder of 
the food consisted entirely of beetles, about one-third of which 
were Anomala binota,ta. 

S 'Um mar y of th e Family. 

Only seven per cent. of the food of the forty-seven members ot 
this family (commonly called seed-eaters) consisted in fact of 
seeds; and insects made up all but two per cent. of the remain­
der. The most interesting items on the general list are canker­
worms forty per cent., predaceous beetles (Carabida:) two per cent., 
and Anomata binotata six per cent. 

ICTERIDM. Blackbirds. 

MoLOTHRus ATER, Bodd. CowBIRD. 

A single wandering specimen of this bird contained only Scar­
abreidre, including Aphodius, and a few other Coleoptera, with 
about sixty per cent. of corn and some seeds of Polygonurn and 
other plants. 

AGELJEUS PH{E ICEUS, L. RED-WI GED BLACKBIRD. 

Two specimens of this bird, which were also accidentally in the 
orchard, had fed about equally upon insects and upon wheat and 



14 The Regulative Action of Birds upon /meet Oscillatiom. 

other seeds. The Lepidoptera (twenty-seven per cent.) were 
nearly all the larvre of Nephelodes violans. Of the Coleoptera 
(eleven per cent.), part were AnoJ?ala and Elateridre, and the 
remainder consisted of specimens of Tanymecus corij'ertus, eaten 
by one of the birds. A grasshopper had also been taken by one, 
making ten per cent. of the food; and traces of Hemiptera were 
recognized. 

lcTERUS GALBULA, L. BALTIMORE ORIOLE. 

Not common. Three were shot. 'rhese had fed only on 
insects,-Lepidoptera forty per cent. and Coleoptera sixty per 
cent., the former all canker-worms, and the latter chiefly Anomala 
binotata (fifty per cent.). Six per cent. of Cerarn bycidl'e and two 
of Rhynchophora should also be mentioned. 

lcTERUS SPURIUS. L. ORCHARD ORIOLE. 

This bird was common in 1881, although but two were shot; 
but was not noticed the next year. More than three-fourths of 
the food of these consisted of canker-worms, and other caterpil­
lars made an additional twenty per cent., leaving but three per 
cent. for ants. 

QuISCALUS PURPUREUS ..iENEUS, Bartr. BRONZED GRACKLE. 

Wandering specimens of the grackle were seen, and a few 
were apparently roosting in the trees at night. But three were 
shot, all of which had fed chiefly upon corn, which amounted to 
sixty-two per cent. of their food. Fragments of a crawfish were 
found in the stomach of one. Half the thirty per cent. of Cole­
optera were Carabidre, including a specimen of Calosoma calidum, 
and the remainder were nearly all Lucanidre (Dorcus, eight per 
cent.) and undetermined Elateridre. 

Summary of the Family. 

The five species of this family mentioned were represented by 
but eleven specimens, which, taken together, were found to have 
made two-thirds of their food of insects, the remaining third of corn 
and wheat with a few seeds of weeds. Canker-worms, eaten by 
the orioles, only amounted to one-fourth of the food of the whole, 



The Regulative .Action of Birds upon .Insect Oscillations. 15 

and Coleoptera to a little more than another fourth. Of these, Cara­
bid.. made four p r cent., Cerambycidre two, Rhynchophora one, 
and Anoma,la binotat if urteen. 

TYRANNID.JE. Flycatchers. 

TYRANNU CAROLI "EN IS, L. KINGBIRD. 

This specie.s was not uncommon, but only three were shot. 
Two of these, to my surprise, were found to have eaten canker­
worms, which made more than a fourth of the food of the whole. 
Five per cent. of the remainder consisted of undetermined Hem­
iptera, and all the balance was Coleoptera. Seven per cent. was 
Elaterida~, two Larnpyridre, and more than fifty-eight Scarabrei­
dre, all Anomala except thirteen per cent. of Apliodius inquina­
tus, eaten by one of the birds. 

CoNTOPUS VIRENS, L. WOOD PEWEE. 

Three of these were shot, none of which had taken canker­

worms. Their food consisted chiefly of flies and gnats, which 
amounted to fifty-five per cent. Thirteen per cent. of Aphodius 
and ten per cent. of Ips, with a few ants and other Hymenoptera, 
are also worthy of mention. 

EMPIDONAX TRAILL!, Aud. TR.A.ILL'S FLYCATCHER. 

Two specimens, shot in 1882, had eaten only insects, one-fourth 
of which were canker-worms, and one-third Icbneumonidre. 
Another fourth consisted of Coleoptera, nearly half of which 
were Anomala; and ten per cent. were ants and other Hymenop­
tera. 

EMPIDO AX FLAVIVENTRIS, Bd. YELLOW-BELLIED FLYCATCHER. 

A single specimen had eaten a number of Lepidoptera and 
their larvre, but no canker-worms. Half the food was Coleoptera, 
nearly all Aphoclius and Anomala binotata,-fifteen per cent. and 
twenty-five per cent. respectively. The little Psenocerus was 
likewise taken by this bird, and a specim n of H ymenarcys 
(Hem1pt ra} 



16 The Regulative Action of Birds upon Insect Oscillations. 

Summa1·y of th e Family_. 

The nine flycatchers taken had eaten only insects, of which 
nearly half were Coleoptera, and the remainder were about 
equally distributed between the Hemiptera, Lepidoptera, and 
Diptera. Canker-worms make fifteen per cent. of the whole, and 
Anomala binotata seventeen per cent. The Scarabreidre include 
all but ten per cent. of the Coleoptera. 

CUCULIDJE. Cuckoos. 

CoccYzus ERYTHROPHTHALMus, Wils. BLACK-BILLED CucKoo. 

Three-fourths of the food of a single specimen shot consisted 
of canker-worms, other caterpillars making an additional twenty 
per cent. Anomala binotata was the only remaining element. 

PIClDJE. Woodpeckers. 

MELANERPES ERYTHROCEPHALUS, L. RED-HEADED WOODPECKER. 

This bird was abundant in the orchard, evidently nesting in the 
trees, although but four specimens were shot. Two of these had 
eaten corn, which amounted to twenty per cent. of the food. 
Fifteen per cent. was canker-worms, and twenty-four per cent. 
Carabidre (eaten by two of the birds), including Calosoma, Scar­
ites, and several Harpalids. Twenty-nine per cent. of Scarabrei­
dre embraced a Canthon and some specimens of Anomala bino­
tata. Melanotus and other spring-beetles were also eaten by two 
of the birds. 

CoL.APTES .AUR.ATus, L. FLICKER. 

A single specimen, killed m 1881, had fed only on ants, the 
usual aliment of the bird. 

COL UMBIDJE. Doves and Pigeons. 

ZEN.AIDURA CAROLINENSis, L. MouRNING DovE. 

Several mourning doves were seen, and a single specimen was 
taken. Three-fourths of the food of this was corn, and the 
remainder the seeds of some leguminous plant. 



Tfu, Regulative Actio11 of Bfrrl.~ upon Insect Oscillations. 17 

PERDI IDJE. Quail and Partridge .. 

0RTYX VIRGI JANA, L. Q AIL. 

Two quails were ·hot, among half a dozen seen. All but four 
per cent. of their f od consi ted of corn and other seeds, chiefly 
those of ompositre. A single chrysomelid, a rhynchophorous 
beetle, and a arabid were the only insects found. 

Besides the pe ies of birds above mentioned, the following 
were noted rarely in the orchard, but no specimens were secured: 
and Vi? o 0U-1Jac it.·, 'turnelta, mctyna, Cyanurw:; C1'istatv,s, and 

ltceturn JJ lasgica. The blue jay was seen eating canker-worms in 
the trees. The total number of species observed in the orchard wa 
therefore forty, and the number of specimens obtained and studied 
was one hundre<l and forty-one, representing thirty-six of the 
species. Twenty- ix of thes species had been eating canker­
worms, which were found in the stomachs of eighty-five speci­
mens. That is to ay, seventy-two per cent. of the species, and 
sixty per cent. of the specimens, had eaten the worms. Taking 
the entire a semblage of one hundred and forty-one birds as one 
group, we find that thirty-five per cent. of their food consisted of 
canker-worms; and if we exclude the species evidently merely 
accidental in the orchard, the average of canker-worms in the 
food of those properly belonging there rises to about forty pe 
cent. 

For a correct estimate of the probable effect of the birds 
in limiting the increase of the canker-worm, it is necessary to 
take into account some of the features of its natural history. 
The larval life of the insect lasts about one month, after which it 
enters the ground and pupates, where it remains until the follow­
ing spring. The imagos, t he females of which are wingless, 
emerge about the middle of April. They lay their eggs upon 
the bark of the trees, usually at night, remaining concealed upon 
the ground by day under fallen leaves and other rubbish. The 
eggs remain upon the trees about a month before the worms 
emerge, when the latter crawl up the trunk and commence their 
attacks upon the leaves. The pest is consequently exposed to 
destruction from the time it emerges until it disappears again, the 
adults falling an easy prey to birds which search the ground for 



18 The Regulative Action of Birds upon Insect Oscillations. 

food, and the eggs to the small species which pry about the trunks 
of trees. The entire period during which the insect is doubtless 
fed upon by birds will usually amount to somewhat more than 
two months. 

Besides the abundance of the canker-worms noted in the food 
of these birds, it is evident that two. or three other species of insects 
occurred in this situation in extraordinary numbers, especially the 
vine leaf-chafer (Anornala binotata) and a small borer (Psenocerus 
supe1·notatits). The purple cut-worm (Nephelodes violans) was 
also somewhat commoner than usual. The Anomala was eaten 
by thirty-nine of the specimens, representing fifteen species, and 
amounted to eleven per cent. of the food of all the birds taken in 
the orchard. Many of these were too small to feed upon so large 
an insect, and a better illustration of the abundance of this 
beetle may be gathered from the food of th~ thrushes and blue­
bird. Of thirty-two specimens of these families, nineteen had 
eaten the vine leaf- chafer, which amounted to twenty-seven per 
cent. of the food of all. Only fourteen of the same birds had 
eaten the canker-worm, which amounted to less than twenty per 
cent. of the food. It seems likely, therefore, that some of these 
birds were attracted to the orchard, not by the canker-worms, but 
by the superabundance of Anomala. The unusual frequency of 
P senocenis supernotatu,s, a small long -horned beetle found upon 
\he trees, is shown by the fact that of the twenty-five small arboreal 
birds (Paridre, Troglodytidre, and Mniotiltidre ), thirteen had eaten 
this beetle, which composed nearly one-tenth of their food. 

We have next to make the comparison of the food 
taken in the orchard by the species most abundant there, 
with the food of the same species, taken el8ewhere under 
ordinary circumstances. For the purpose of this compar­
ison I have selected the robin, the catbird, the black-throated 
bunting (Spiza arnericana), and the indigo bird (Passerina 
cyanea). In the table of the ordinary food of the robjn for 
May, published in Bulletin . 3 of this series, as represented by 
fourteen specimens, caterpillars amounted to but twenty-three per 
cent., whereas in the orchard they rise to fifty-four per cent. This 
difference between the averages is almost exactly accounted for 
by the ratios of canker-worms and N eplielodes violans not appear­
ing on the former table; these together a~ounting to thirty-five 



'the R egulative Action of Birds upon insect Osci.llations. 19 

per ent. otwith tanclino- th number of Anomala eaten in the 
or hard, th ratio of the araba:id;_ are substantially the ame, 
a the ordinary food of the robin in lay consi ts largely of June 
beetle . The surplu of Lepidoptera s em to be balanced by a 
deficiency in all the other ord rs, no one of which ris to the 
averag of it ordinary food in May. The lo s is gr ate t, how­
ever, in th Diptera, which drop from eleven per cent. to nothing. 

omparm the record of the fourteen catbirds shot in the 
orchard with that of twenty-two obtained in miscellaneous itua­
ti n , we not , :fir t, that the caterpillars on the :first table are 
more than twice tho e of th s cond,-twenty-six in the one, and 
twelve in the other; and that this differen is evidently due to 
the fifteen p r cent. of canker-worms taken by the birds of the 
first group. Thi hows that the catbi rd, like the robin, had 
simply add d the a11ker-worm aten to it u ual ratio of cater­
pillars. A more striking difference is shown in the totals of 

oleoptera which stand at fifty-six per cent. in the orchard birds, 
and tw nty-three in the others. This, again, is evidently due to 
the abundance of Anumala binotata · for when the ratio of this 
insect is subtra ted from the total of Coleoptera, the remainder is 
twenty per cent. a against twenty-three of the ordinary food. 
These e, ce ive ratio of Lepidoptera and Coleoptera are com­
pensated by deficiencies in the Diptera, Arachnida, Myriapoda 
and Orthoptera, e pecially in the three :first named groups. The 
decided preference of this bird for ant is shown by the fact that 
the u ual ratio of these insects is scarcely diminished, fourteen 
per cent. having been taken in the orchard and eighteen else­
where. 

Fourteen of the black-throated bunting ( piza ame1·icana), 
killed in the orchard, are to be contrasted with twelve shot in 
fay from various situations. A striking difference is seen at 

once in the insect ratios, which amount respectively to eighty­
eight and forty-seven per cent. This surplus of insects eaten by 
the orchard birds is readily traced to the orders Lepidoptera and 
Coleoptera. Of the former these birds had eaten more than three 
times their ordinary average, and of the latter nearly four times 
the usual amount. The excess of Lepidoptera is clearly due, as 
usual, to the presence of the canker-worms, since the balance left 

3 



26 The R egulative Action oj Birds upon insect Oscillations. 

after subtracting the canker-worm ratio from the average of that 
order taken by the first group, differs by only three per cent. from 
the average taken by the second group. The discrepancy in the 
ratios of Coleoptera is not so easily explained, but is distributed 
among several genera of Scarabreidre and the small scavenger 
beetles. The excess of these two orders is compensated princi­
pally by diminished ratios of veg etation, which amount to only 
six per cent. in the birds shot in the orchard, and fifty-two per 
cent. among those taken through the country at large. Diptera and 
all the lower orders of insects as well as Arachnida and Myriapoda, 
are also omitted from the food of the orchard birds. 

Insects composed ninety-seven per cent. of the food of eighteen 
indigo birds (Passe1·ina cyanea) shot in the orchard, and but fifty­
seven per cent. of the food of fifteen individuals taken elsewhere, 
the balance in both cases being seeds, chiefly Setaria, Polygonum 
and wheat. The e~cess of insects in the orchard specimens 
appears under L epidoptera and Coleoptera, the former sixty-seven 
per cent., the latter twenty-nine, as compared with twenty-eight 
and nineteen per cent. respectively, in the other group. The 
Lepidoptera of the orchard birds are nearly all canker-worms, as 
are likewise t en per cent. of those taken by the specimens from 
various situations. The difference in the ratio of Coleoptera 
taken by the two groups was exactly compensated by the ten per 
cent. of Anomala binotata eaten in the orchard. The excess of 
caterpillars and beetles taken by the former group, is partly com­
penf?ated also by the almost total disappearance of all other 
insects from the food. 

What, now, may we conclude, from the above data, respecting 
the influence of birds upon such entomological insurrections as 
are illustrated by the uprising of the canker-worms in Mr. Rob­
ison's orchard? 

Three facts stand out very clearly as results of these investiga­
tions: 1. Birds of the most varied character and habits, migra:qt 
and resident, of all sizes, from the tiny wren to the bluejay, 
birds of the forest, garden and meadow, those of arboreal and 
those of terrestrial habit, were certainly either attracted or 
detained here by the bountiful supply of insect food, and were 
feeding freely upon the species most abundant. That thirty-five 



The Regulative Action of Birds upon Insect Oscillations. 21 

per cent. of the food of · all the birds congregated in this orchard 
should have consisted of a, single species of insect, js a fact so 
extraordinary that its meanjng can not be mistaken. Whatever 
power the birds of this vicinity possessed as checks upon 
destructive irruptions of insect life, was being largely exerted 
h re to restore the broken balance of organic nature. And while 
looking for their influence over one insect outbreak we stumbled 
upon at least two others, less marked, perhaps incipient, but evi­
dent enough to xpress themselves clearly in the changed food 
ratios of the birds. 

2. The comparisons made show plainly that the reflex effect of 
this concentration on two or three unusually numerous insects was 
so widely distributed over the ordinary elements of their food 
that no especial chance was g iven for the rise of new fluctuations 
among the species commonly eaten. That is to say, the abnormal 
pressure put upon the canker-worm and vine chafer was compen­
sated by a general diminution of the ratios of all the other ele­
ments, and not by a neglect of one or two alone. If the latter 
had been the case, the criticism might easily have been made that 
the birds, in helping to reduce one oscillation, were setting others 
on foot. 

3. The fact that, with the exception of the indigo bird, the 
species whose records in the orchard were compared with those 
made elsewhere, had eaten in the former situation as many cater­
pillars other than canker-worms as usual, simply adding their 
canker-worm ratios to those of other caterpillars, goes to show 
that these insects are favorites with a majority of birds . 

• 



22 The Regul,ative Actwn of Birds upon !meet Oscillations. 

TABLES OF THE FOOD. 

' ai 
:S? 
+> 
t>-. 

Turdidre. ai ai 'O Mniotiltidre. 0 
:S? 'O bl) 
3 :~ 0 

o:l :... 
CIJ ~ __t4__ 

'O ' ~ 'O ' 'O s.,; i :... :... a, a, £ ..ci a, . o:l £ a, 
o:l ......... 

"' A.a, 
~ 

'O . 
~ 

o:l..O ~-::s A. a, ci ~ - ·;;-; ~ 0;.. 

..a o:,'O a, ;,-c '"O i:c ;.. o:l ~~ 
<) "" 

;.. a, . :... ..... 
~~ -00 8 ,d .~ 

~ 
a, :... 1~ Q:... 0 

,d :... ~ <) "' c;) +> ,:l A. 
d;.. 

d o·~ in ..... ~d !=~ d :... :.a o:,..C:: a, a, ..0 ~~ /4s.,; <) a, 

:.c :0 I:! .;; a, c:iu "' <l 8 <) a, "" a, t>-. =i +> 0 ""' E ::s ::l ::s ..c:: 
~~ 

...... ;.. :... +> 0 o:l :... 0 0 a, ~ i:q::, o;! 0 
~ 0 i:q 8 i:Q tel 8 CIJ i:q ~ __t4__ - -

Number of Birds .. .. . . . 9 14 4 27 5 2 5 1 5 2 4 1 2 15 

KINDS OF FOOD. NU~ER OF SPECIMENS AND RATIOS IN WHICH EACH ELEMENT 
OF FOOD WAS FOUND. 

9 14 4 27 5 2 5 1 5 2 4 1 2 15 
Animal Food . . .. . . .. . . . . 1.00 1.00 1.00 1.00 1.00 1 .00 1 00 1.00 1.00 1.00 .95 1 00 1.00 .99 

3 3 
I . MOLLUSCA. . . . . . .. .01 . ... . ... t . . .. . .. .. . ... 

9 14 4 27 5 2 5 1 5 2 4 1 2 15 
II. INSECT A . . . . . . . . ... .93 .98 .94 .96 .98 1.00 .91 1.00 .94 1.00 .95 

1 :i:11 :00 
.97 

4 11 2 17 2 2 2 3 8 
1. Elymenoptera . ' ' .... .01 .14 .03 .08 . . . . . .. . .05 . . . .02 .07 .04 .03 

4 11 2 17 2 2 3 5 
Formicidre .. ... . ... . .01 .14 .03 .us . . . . . . . .05 . ... .06 .04 . . . . . . . . .02 

9 12 4 26 3 2 5 1 5 2 4 1 2 15 
2. l epidopter a . . .... . . .54 .26 .22 .34 .17 .61 .39 .80 .67 .75 .66 .70 .82 .71 

6 5 1 12 

I -
Noctuidre (larvre) ... .28 .04 .05 .12 . ... ' . . . .. . . . . . . . . . . . . .. . . . . . .. . .. 
Nephelodes violans 3 1 4 

(larvre) ........ .14 .01 . .. . .05 . ... . . . . ... .. . . . . .. . . . . . . .. 
3 8 2 13 1 2 3 1 5 2 4 1 1 14 

Anisopteryx vernata .21 .Hi .12 .16 .12 .61 .46 .80 .67 .65 .66 .70 .37 .64 
3 1 2 4 1 2 10 

3. .Diptera .. ... . .. . . . . .. . . . . . . . . . . ... .. . . . ... .04 . . . . .01 .02 .06 .05 .04 .03 
2 1 4 1 2 8 

Gnats . ...... . . ... . . .. . . . . . . "27 .... .03 . . . . . . .02 .05 .05 .04 .03 
9 14 4 5 2 5 1 5 2 4 1 1 14 

4. Ooleoptera . .... .. .. .36 .66 .67 .51 .66 .39 .13 .20 .23 .11 .19 .08 .08 .18 
4 5 3 12 3 1 1 1 2 

Carabidre . .. . .. . .... .01 .04 .12 .04 .23 . ... .01 . .. . .01 .. . . .01 . ... . . . . .01 
1 1 1 1 

Staphylinidre ... . . .. . 04 . .. . .. . . .01 . . . . . ... . . .. . ... . . .. . .. . ... . . ... .05 .01 
1 

Phalacridre .. ....... . .. . . . .. . . . . .... . . . . . . . . t . ... . . . . . .. . . . . . . ... .. .. . . .. 
5 2 1 8 

Histeridre ... ........ .01 t .02 .01 ... . .. .. . .. . .. . . . . . . . ... . .. . ... . ... . . ... 
6 12 3 21 5 1 1 1 1 3 

Scarabreidre . . ... . ... .18 .49 .44 .38 .36 ... . .01 . .. . .06 .05 .02 . ... .... .03 
3 10 2 15 4 

Anomala binotata .14 .36 .14 .26 .36 . . .. .... . .. . . .. . . . . .. . . . . . . . ... . ... 
6 1 3 10 1 

Elateridre . .. . .. . ... .11 .01 .06 .05 .... .... .01 . ... .... . ... . .. . .. .. . ... 
1 1 2 

Lampyridre . . . . .. . • .. . . .. .. . . .. .. ... . . .. . . ... .20 .04 . ... .... . . . . ... .03 
1 2 3 2 3 1 1 10 

Cerambycidre . .. . ... .. . . . . . . . . . . .. .. . . . . .26 .04 . ... .12 .06 .15 .15 .03 .10 
Psenocerus SU- 3 2 3 1 1 10 

pernota tus .. ... . . . . .... .. . . .. . . ... ... . . . .. .12 .06 .15 .15 .03 .10 
1 

Chrysomelidre .. . .. .. . . . . .. .. .... . ... .05 . . . . .. . . . .. . . ... .. .... ... . . .. . . .. 
3 3 1 7 1 1 1 1 

Rhy nchophora .. . .. .01 .01 .03 .02 . .. . .10 .01 . . .. t .. . . .... . ... . . . . + 
3 6 9 3 4 2 1 1 1 2 7 

5. Hemiptera .. . . . . . . . . .02 .02 . . . . .02 .15 ... . .10 . .. . .01 .05 .01 .05 .06 .02 



The Regul,ative Action of Birds upon Insect Oscillations. 23 

Number of Birds .. 

KINDS OF FOOD. 

. Homoptera ... . . . .. . 

Apbides ... ..... .. 

TABLE F THE FOOD-Continued. 

9 14 4 27 5 2 5 1 5 2 4 1 2 15 

NUMBER OF SPECIMENS .AND RAT IO IN WHICH EACH ELEMF.NT 
OF FOOD WAS F OUN D. 

1 
. 02 .... 

1 

1 
.05 .... 
1 

.05 ... 

Tettigon idre .. . .. 
3 

Heteroptera ........ .02 
4 6 3 
02 .. .. .02 .15 .. 

.02 .... 
1 

.06 ... 
1 

1 1 
.05 t 

Aradidre ........ . 

Lygreidre . ..... . . . 

hinchbug .. . . 
1 

Coreidai . . ... . .. . . .01 
2 3 

Cydniclre ......... . .01 .02 

Ill. ARACHNIDA . . .. .. . 
2 2 

IV. MYRIAPODA .. 05 .02 
VI. VERMES (Lumbri- 1 

cus) .. ..... . . . .01 

Vegetable Foorl (seeds). 

1 
.01 
5 

.. .01 

1 5 
.06 . 03 

1 
.01 

3 

.02 ... 
1 

.02 ... . 
1 
.02 .... 

.15 ..... 
2 3 3 

.02 .06 .... .06 .... 
1 

.01 .. 

1 1 
.05 t 

1 1 5 
t t .02 .... 

1 1 
.05 .. . .01 



24 The R egulative Action of Birds upon Insect Oscillations. 

TABLES OF THE FOOD-Continued. 

rJ 
~ rJ 

'Cl 

'Cl ;§ 
·a 

·a ;a Fringillidre . 
0 Q) Q 
c:.i 0.. .:: 

Icteridre. 

1-1 s -~ 
~ ~ ~ -

Number of Birds .. . .. . . 

KIN DS OF F OOD. 
NUMBER OF SPECIMENS AND RATIOS IN WHHJH EACH ELEMENT 

OF FOOD WAS FOUND. 

3 7 1 I 1 1 8 3 14 2 18 47 1 2 3 
Animal Food .. .. ... . . .. 1.00 1. 00 1.00 .30 .65 .96 1.00 .94 .80 .97 .93 .30 .50 1.00 

1 1 
I. M OLLUSCA .. .. . . . .. ,, . ... .06 . . . . .01 . . . . . . . .. . . 

3 7 1 1 1 8 3 14 2 18 47 1 2 3 
II. INSECTA .. ......... . 1.00 1.00 1.00 .30 .35 .95 1.00 .88 .80 .97 .91 .30 .50 1.00 

1 1 3 3 1 2 8 
1. Hymenoptera ... . . . . . . + .02 . .. . . . . .03 . . . . .01 .02 .01 .01 .. .. . . . . . . . . 

1 1 2 
Formicidre ... . . . . .. .. . . .. .. ... . . . . . . . . .01 + . .. . .. . + ... . . .. . . .. 

1 1 
Tenthredinidre . . . . . .. . .. . . . . . .02 . . . ... . . .. .01 ' . .. . . . ... 

3 7 1 7 3 13 2 17 43 2 3 
2. Le.,pidoptera .. . ... . . .79 1.00 . . . . . .. . .30 .32 .47 .65 .63 .67 .57 . ... .29 .40 

2 2 1 
Noctuidre. ... . .. .. . .. . . .. . . .. . . . . .. . .14 . . . . ... .04 . .. . .25 . .. . 

Nephelodes vio- 1 
lans (larvre) . .. . . . ... . . .. ' . . . . .. . .. . .. . . . . . .. . ... .25 

3 7 2 1 10 1 17 31 1 3 
Phalren idre (larvre) .44 1.00 . .. . . . .. . .. . .16 .20 .46 .05 .60 .41 . . . . .01 .40 

Anisopteryx ver- 3 7 2 1 10 1 17 31 1 3 . nata ... .. .. .. .44 1.00 . . . . . . . . .16 .20 .43 .05 .59 .40 . . . . .01 .40 
1 7 1 8 

3. Diptera . . . .. . . ... . . . .03 . .. . . . . . ... . . ... .28 .05 . . . . . . . . . . .05 ... . .... . ... 
7 1 8 

Gnats .. .. . .. . ....... . ... . . .. . . . . . .. . . . ... .28 .05 .. . . . ... . ... .05 . .. . . ... . . .. 
1 

Muscidre ...... . . . . . . . 03 .. . . . .. . . . . . . . .. . . . . . . .. . ... . . .. . . . . 
2 3 1 1 1 7 3 11 2 18 43 1 .2 2 

4. 0 oleoptera . ........ . .15 + .98 .30 .05 .25 .47 .22 .15 .29 .26 .30 .11 .60 
2 1 3 4 

Carabidre .. . ........ . .05 . . . . . ... .30 . ... .. . . .. . . .04 . . . . .. . . .02 . ... ... . . ... 
1 1 

Nitidulidre . . ..... ... . ... . . .. ... . .... . . .. . . . . .... .01 . ... .. . . + . ... .... . ... 
1 3 1 5 

Histeridre . ... .. .... ... . . .. . . .. . . . . . ... . · ·•· .03 .04 . ... .01 .01 .. .. ... . . .. . 
1 

Trogositidre . . . ... .. ... . . .. . .. . . . . . .. .. .. . .. .. ... . "'i' . .. . . .. ... . .01 
1 3 1 · 3 3 7 9 23 1 1 3 

Scarabreidre .... .. . . . .08 + .98 ... . . .. . .14 .08 .11 .02 .15 .12 .25 .03 .50 
1 2 2 1 4 9 1 3 

Anomala binotata .08 .. . . . . .. .. . . .. . . .09 .04 .02 .10 .06 . ... .03 .50 
1 2 3 1 1 

Elateridre .. . ... . . .. ... . .. .. ... . . . .. .. . .. .01 . . . . . . .. .01 .01 . ... .04 .01 
1 1 

L ampyridre . .. .... .. . . . . .... . . .. . .. .. . . . . .. . . .. .. .. t . . . . + . . .. ... . . .. 
1 3 

Cerambycidai . .. ... . . 02 .. .... .. .. .. . . ... . . . . . .. .. .... . . . . .. . . ... ... . .06 
Psenocerus super- 1 

notatus . . . ... .... .. . . .... .... ··• · . ... . ... .. . . . . .. .. . . . . .. . .. . .. . .02 
2 2 1 

Chrysomelidre . .. . . . .... .. . .. .. .. .. .01 .. .. .. . . ... . . . .. + .02 . .. . . . .. 



The R egulative Action of Birds 'ttpon Insect Oscillations. 25 

TABLE OF THE FOOD -Continued. 

bD ;! 

I 

Cl) 0 0 -0 0 
Q) "i -0 ... 

a: -c :§ .:: a: 0 Q) :.. Q) 'Cl c:<! 

> ::.., bl) 0. 0 
..., 

Q) ... 
X ~ c:: ~· :.. c:<! • ..., . -d 'Cl 0 
d c.c ·- .SC 

en :.. obll 11,,.!:d :.. ci· 
bl) 

~ d ~o bl) c:<! :.. 0 d d 
~ bll'E Q) 

Q d o 0. .Q•- Q) Q) 'C O·- :.. 
!::: <) 0 i;:.:: -~ ..., .... ... p 0 

:; ·:-~ en 0 .0 <11 0 ... · - ,,0 s :.. en .,. c:<! 
0. .lt1 ~ :0 l::;..!:d 

Q) 0 0. :s •o bl) <ii :.. d l::::l . !:' ~~ 
Q) ... ' <) ~ 

~ " 6 = en -~ :gc 'Cl .... e: "Od <ii 
~ 

Q) ..... Q) .Q 0 0 0 ~~ ;.) 0 ~ :,..; v r:i:. ~ ~ ~ E-1 0 ~ 

Number of Birds . ...... 3 7 1 I 1 1 8 a 14 2 18 47 1 2 3 

KINDS OF FOOD . 
NUMBER OF SPECIMENS AND RATIOS IN WHICH EACH ELEMENT 

OF FOOD W A.S FOUN D. 

1 3 6 2 6 18 1 1 
Rbynchopbora .. .... .. . . ... . .. . ... .01 .08 .02 .08 .03 .03 . ... .04 .02 

1 5 1 1 7 1 
5. Hemiptera .... .. .... .03 . .. ... . . .06 .01 . . .. . ... + .01 . .. t . .. . 

1 1 1 
Homoptera .. .. ... .. .. . . ... . . . . . . . .. . .. . . .. . ... + + . .. t . ... 

1 1 
Hetcroptera .. .. .. .... .. . .. . .. . .. .03 . . . . . . . . .. + ... . ... . ... 

1 1 
Lygreidai . . .. . .. . . .. . ... .. . . . .03 . .. .. ... . .... .01 . . .. ··•· . .. . 

1 
Cydnirlai . . . . . . 03 . ... .. ... .. .. . .. . . ... . ... . . .. . .. ... . . . . . 

6. Orthoptera (Acri li- 1 
d re) . . .. .. .. .. . .. . . . . .. . . .. .. . . . ... .... . ... . .. . .. . .10 . ... 

1 6 2 9 
III. ARACHNIDA .. .. . . . ... . . . . .30 .01 + .. .. . ... .01 . .. . . . ... 

1 1 4 3 2 6 17 1 2 
Vegetable Food ( eed ) . .. .. . .. 70 .35 .04 . . . .06 20 .03 .07 .70 .50 . ... 

2 2 
Compositre ....... ... .. . . ... ... .. . . ... . ... .01 .01 .. . . .. . . .. 

1 1 
Polygooum . .... . .. ... . .. . . . . . . . . . .. . . . . ... . .. .05 05 . ... 

1 1 1 
Wheat ...... ... .. . . . . . . ... . ... .. . . . .05 . . . .02 . . . . .45 . . .. 

1 2 2 2 7 
Setaria .... ... .. ... .. .... . .. - . .. ... .15 .01 . . + . . . .01 .01 .. . - -· . . .. . 

1 
Corn .. .... .......... ... . - . - .. ... ... . .. - .. ... . ... .60 . . . . --- . 

1 1 
Panicum .. .. - . - - . . .01 . .. + . . .. __ . 



26\ The .Regulative Action of Birds upon Insect bsciilations. 

TABLES OF THE FOOD- Continued. 

ai I ai ai -0 
:0 -0 

Icteridre Tyrann idre. -0 P ic idre . ''3 
'; 8 :a ::: Q 

0 
I'< 

::: Q) 

~ (.) 0.. ----- -
I'< 

a5 Q) 

a5 ..c: 
a5 :;; Q -0 ~ 

:§ 
..., 

0 Q a.i ol Q) •• ol Q ;.::: Q) -::, -~ A I'< I'< Q) 
t>, .:: UQJ 

0 C!l -::i ~ 
~ 

a5.c Q).!:tl bO I'< Q) .D Q ~o -0 <) 
A 'Cl 'Cl ~ 0.. '..., .DO ce Q) ;.; 

I'< Q) :!' i:: ~ '.!:tl Q) 0. Q) A ol N 'Cl .-
~ .!,jc;, ..C:-o ,....; _; 

..c: i:: ~ bO ...... ~~ ~ I'< -~ 0 ·.; :.l::: · o 
;~ 

ol ::: Q 0 ..., .!: 0 Q)~ 
..., ~u -0 0 ..., 

0 ::: ~ :.., 0 
~ 

I'< 0 ~~ 0 
0 c::i 8 ~ 8 ~ 8 'A fa;< ~ ::s CJ -- - -

Number of Birds ... . .. 2 3 11 3 3 2 1 9 1 4 1 5 1 2 

KINDS OF FOOD. NUMBER OF SPECIMENS AND RA'fIOS IN WHICH EACH ELEMENT 
OF FOOD WAS FOUND. 

5ol 
' I 

11 3 3 2 1 9 1 4 1 5 2 
Animal ~~ood . . ... .. .... 1 .38 .68 1.00 1 .001 00 1.00 1.00 1 00 .80 1.00 .84 .. . . .04 

2 3 11 3 3 2 1 !l 1 4 1 5 2 
I I. lNSECTA. . . .... . . . ... 1.00 .30 .66 1 00 1.00 1.00 1.00 1.00 1.00 .so 1.00 .84 · ·· - .04 

1 1 1 2 2 1 6 1 1 2 
1. Hymenoptera . .... . . .03 . . . .01 .05 .12 .48 .02 .16 . . . . .01 1.00 .21 . ... . ... 

1 1 1 1 2 1 1 2 
Formicidw . . . .. . . . . .03 .. . . .01 . .. .04 .05 . .. . .02 . ... .01 1.00 .21 . . .. . . .. 

1 1 
lchucumonidre . . . . . .. . .... . . . . . . . . . . . .33 . . .. .07 . . . . ... .. . . . . .. . ... . .. . 

2 7 2 1 1 1 5 1 1 1 
2. Lepidoptera . .. ..... .97 . . . .34 .28 .05 .25 .30 .20 .95 .15 .. . . .12 . . .. . ... 

1 
N octu idre(larvre) .. . . . . . . . .05 . . .. . . . . . . . . .. . . . .. . . . . . . .. . . .. .... . ... . ... 

Ncph~lodes vio- 1 
lans (larvre ) . . . . . .. .05 . .. . . . . .. . . . .. . . . . . . . . . . .. . . . . . . ... 

2 6 2 1 3 1 1 1 
Pha lrenidre (larvre). .77 . . . .25 .28 ... .25 . ... .15 .75 .15 . . .. .12 .... . ... 

2 6 2 1 3 1 1 1 
Anisop teryx vernata .77 . . . . .25 .28 .. . .25 . . . . .15 .75 .15 . . .. .12 .. .. . ... 

3 1 4 
3. Dipte1·a . .... . . .... .. . . . . . . . . . . . . .55 . .. . .08 .19 . . .. . .. . . .. . . .. ... . . ... 

1 1 
Tipulidre .. .. .. ... . . . . . . .. .. . . . . .. . .08 .01 . .. . . . . . ... .. . . . . . . ... 

1 1 
Gnats .... . ... . ... ... .... . . . . . .. . ' .. .23 ' .. . ' ... .OS .. . . . ... . . . . . ... . . .. . ... 

2 2 
Muscidre .. . . . . .. . ... . .. . . . . . .. . .32 ... . .10 . . . . . .. . . .. . . . . . . ... . .. . 

3 8 3 2 2 1 8 1 4 4 2 
4. Ooleoptera . ......... . .. . .30 .29 .67 .28 .25 .50 .43 .05 .64 . .. . .51 . ... .04 

3 3 2 2 1 
Cara bidre .. ... .... . . . .. . . .16 .04 .. . . . . .. . ... . . . . .. . . .. . . .24 . .. . .19 . . . . .01 

1 1 
Nitidulidre .. . .. . ... . . .. . ... . .... .10 . ... .. . . .03 . . . . .. . . . . .. . . . . . ... . ... 

1 
Trogositidre .. .. .. .. . . . . . . . . t . . .. ... . .... . . .. .. .. . . .. . . .. .. . . ... . . ... . . . . 

1 1 
Lucanidre .. .. . . .. . .. . .. . .08 .02 . ... . . .. .. . . . . .. .. . . . ... . ... .. .. . .. . . . . . 

1 6 3 2 2 1 8 1 3 3 
Scarabreidre . .... . . . . .... .01 .17 .58 .18 .10 .40 .33 .05 .29 . .. . .23 . ... . . .. 

4 2 1 3 2 2 
Anomala binotata . . .. . . . . .14 .43 . ... .. . . .25 .17 . ... .04 . .. . .03 . ... . ... 

1 3 1 1 2 2 
Elateridre . .. .... .... .... .05 .03 .07 .. .. .. .. .. . . .02 . ... .09 . ... .07 . . . . . .. . 

1 1 
Lampyridre .. . . ..... .. .. . . . . .. . .02 . ... .. . . .. . . .01 . . . . . . . . . .. . . ... . ... 

3 1 1 
Ce ram bycidre . ...... ... .. . . .02 .. .. ... . . . .. .10 .01 .... .. .. . .. . ... . . .. . . ... 

Psenocerus super- 1 1 1 
notatus . ... .. .... .. . . .01 .. .. .... .. .. .10 .01 .... . .. . . ... . ... . ... . ... 

1 1 
Chrysomelidre .. . . . . . t . . .. . . . . . . .. .... . . .. . . . . . ... .. . . . . · • · · .02 



The R egulative Action of B frds upon Insect OsdllationS. 27 

TABLE OF THE FOOD - Concluded. 

Number of Birds . . .. . . . 2 

KINDS OF FOOD. NUMBER OF SPECIMEN!'! AND RATIOS IN WHICH EACH ELEMENT 
OF F OOD W .AS F OUND. 

Rhynchophora ... . . 
1 3 
t .01 

1 
5. H emiptera ... . . .. . . .. . . . . .. . . t 

1 
H omoptera .... . . . . 

Cy dnidre . . . . .. .. . . 
6. Orthopter a (Acridi -

dre ) .. . . . ... .. ... . 
V. CRUST.ACE.A (C raw - 1 

fish). .. .. . . . .. .08 
3 

Vegetable Food (Seeds) . . . .62 

Leguminosre . . . .. .. . 

Compositre . . .. .... . . 

Polygon um . .. ... . . . ... . 

t 

1 
.02 
1 

.02 
6 

.32 . ... 

2 
.01 
1 

Whea t . . . .. . . .. .. . . . . . . .08 

Seta ria . . ... .. . . . .. . 
3 4 

Corn ... . . . . .. . . . . . . . . . . .62 22 

1 1 
.10 .01 

1 1 
.10 .01 

. . .. 

2 
.20 

. . . . 

. .. . 

2 
.20 

2 
.16 

. .. . . . 

2 
.16 

GENERA. .A.ND SPECIES RECOGNIZED IN THE F OOD. 

1 
1.00 

1 
.25 

1 
.75 

1 
.01 

2 
.96 
1 

.02 
1 

.32 
2 

.03 

1 
.02 
2 

.57 

The following lists are intended to supplement the preceding 
tables and, taken tog ether with them, to present all the details 
concerning the food of the birds observed in the orchard, upon 
which the foregoing discussion is based. In the first list the g enera 
and species recognized in the food of each kind of bird are 
given separately ; in the second the food elements are systemati­
cally arranged, and against the name of each element the names 
of all the species of birds are placed in whose food that element 
was recognized. The :figures preceding the names of the birds 
in the second list indicate the number of individuals in which the 
given element was found: 

TURDIDlE. 

T urdus migratorius · H elix, Hyalina, Limnea humilis, Formica, 
N ephelodes violans, Anisopteryx vernata, E laplu-us ruscarius, 
Staphylinus badipes, Aphodius, A. inquinatus, Phyllo-

4 



28 The R egulative Action of Birds upon Insect Oscillations. 

phaga, Anomala lucicola, A. binotata, Melanotus, Monocre­
pidius, Graphorhinus vadosus, Alydus eurinus, Camus delius, 
R ymenarcys, Polydesmus serratus, Lumbricus. 

Mimus ca1·ol-inensis : Formica, F. fusca, Lasius, L. niger, 
N ephelodes violans, A nisopteryx vernata, Clivina striato­
punctata, Anisodactylus, Rister americanus, R. perplexus, 
Onthophagus, Aphodius, A. inquinatus, Phyllophaga, Anoma­
la binotata, Melanotus, Graphorhinus vadosus, Tanymecus 
confertus, Baris, Sphenophorus, Camus delius, Podisus 
spinosus, Iulus. 

H arporhynchus 1·ufits : Anisopteryx vernata, Chlrenius, Steno­
lophus conjunctus, Rister americanus, R. perplexus, Aphodius, 
Diplotaxis georgire, Anomala binotata, Melanotus, Monocre­
pidius, Baris confinis, Iulus. 

SA XICOLIDlE. 

Sialia sialis : Anisopteryx vernata, Anisodactylus baltimorensis, 
Aphodius, Anomala binotata, Chrysomela suturalis, Diabro­
tica vittata, Coonus delius, Rymenarcys requalis, Euschistus. 

P arus atricapillus : 
tatus. 

PARIDlE. 

Anisopteryx vernata, Psenocerus superno-

TROGLODYTIDlE. 

Troglodytes domesticus : Anisopteryx vernata, Olibrus, Apho­
dius, Monocrepidius auritus, Psenocerus supernotatus, Blissus 
leucopterus, Iulus. 

MNIOTILTIDlE. 

H elminthophaga peregrina : Anisopteryx vernata, Telephorus 
bilineatus. 

D endrceca cestiva : Anisopteryx vernata, Aphodius, T elephorus 
bilineatus, Psenocerus supernotatus. 

D endrceca p ennsylvanica : Anisopteryx vernata, Psenocerus 
s u pernota tus. 

D endrceca striata : Anisopteryx vernata, Aphodius, Psenocerus 
supernotatus. 

D end1·ceca virens : Anisopteryx vernata, Psenocerus superno­
tatus. 

Geothlypis t1·ichas : Anisopteryx vernata, Psenocerus superno­
tatus, Piesma cinerea. 

VIREONIDlE. 

Vireo gilvus : Anisopteryx vernata, Anomala binotata, Tele­
phorus bilineatus, Euschistus. 

AMPELIDlE. 

Ampelis cedrorum : 
A. femoralis. 

Anisopteryx vernata, Aphodius inquinatus, 



The Regulative Action of Birds upon in ect Oscillations. 29 

HIRUNDINIDlE. 

P et1·och liclon lunifrons: Aphodius inquinatus. 

FRINGILLIDJE. 

ot1trnicu,lu · pet8S 1·irws : Setaria. 
i].,izella dom,esti<;a : Anisopteryx vernata, Anomala binotata, 

Bari , etaria, Panicum. 
8pi.zella, rtgrestis: Anisopteryx vernata, Onthophagus, Aphodius 

A. inquinatus, Monocrepidius, Baris, Sphenophorus. 
rpiza amel'icana: H elix, A ·apestemon, Anisopteryx v rnata, 

Anisodactylu , Ips fa ciatu , Aphodius, A. inquinatus, 
Anomala binotata, Sphenophorus, Wheat, Setaria . 

Zwneloclia focloviciana: Anisopteryx vernata, Anornala bi­
notata. 

Passerina cyanea : Aphidius, Anisopteryx vernata, Onthoph­
agus, Aphodius, Anomala binotata, Monocrepidius, Baris, 
Setaria. 

ICTERIDlE . 

.11£olothrus ate?' : Aphoclius, Dibolia aerea, Polygonum, Corn. 
Agelceus pha:,niceus : N ephelodes violans, Anisopteryx v~rnata, 

Anoma1a binotata, Tanymecus confertus, Polygonum, Wheat. 
I cterus galbula: Anisopteryx vernata, Anomala binotata, Phy­

matodes variabilis, Psenocerus supernotatus. 
I cterus spu,riu : Camponotus, Anisopteryx vernata. 
Quisccdus pu1pureus ceneu,s : Calosoma calidum, Dorcus paral­

lelus, Crawfi.sh, Corn. 
TYRANNIDlE. 

Tyrannus carolinensis: Anisopteryx vernata, Aphodius m-
quinatus, Anomala, A. binotata, Melanotus. 

Gontopus vi?'ens: Ips fasciatus, Aphodius, A. inquinatus. 
Empidonax t1·ailli : Anisopteryx vernata, Anomala. 
Empiclonax flaviventris : Aphodius, Anomala binotata, Pseno-

cerus supernotatus, Hymenarcys. 

CUCULIDlE. 

Goccyzus e1·ytfitrophthalmus: Anisopteryx vernata, Anomala. 

PICIDlE. 

Melane1pes erythrocephalus : Camponotus, Anisopteryx ver­
nata, Calosoma calidum, Scarites substriatus, Canthon hud­
sonias, Anomala binotata, Melanotus, Corn. 

COL UMBIDlE. 

Z enaiclU'ra cm·olinensis : Corn. 
PERDICIDlE. 

Chrysomela suturalis, Polygonum, Setaria, Ottyx virginiana : 
Corn. 



30 The Regulative Action of Birds upon Insect Oscillations. 

H eli. · : l Turd us migratorius, 1 Spiza americana. 
Hyalina : l Turdus migratorius. 
L irnncea humilis: l Turdus migratorius. 
Aga:pesternon: l Spiza americana. 
Formica sp.: l Turdus migratorius, 1 Mimus carolinensis. 
F. fusca: l Mimus carolinensis. 
L asiits sp.: l Mimus carolinensis. 
L. nige1· : 3 Mimus carolinensis. 
Camponotus : l Icterus spurius, 1 Melanerpes erythrocephalus. 
Aphidius : l Passerina cyanea. 
Nephelodes violans: 3 Turdus migratorius, 1 Mimus carolin­

ensis, 1 Agelreus phreniceus. 
Anisopteryx vernata : 3 Turdus migratorius, 8 Mimus carolin­

ensis, 2 Harporhynchus rufus, 1 Sialia sialis, 2 Parus atrica­
pillus, 3 Troglodytes domesticus, 1 Helminthophaga pere­
grina, 5 Dendrreca restiva, 2 Dendrreca pennsylvanica, 4 
Dendrreca striata, 1 Dendrreca virens, 1 Geothlypis trichas, 
3 Vireo gilvus, 7 Ampelis cedrorum, 2 Spizella domestica, 1 
Spizella agrestis, 10 Spiza americana, 1 Zamelodia ludovi­
ciana, 17 Passerina cyanea, 1 Agelreus phreniceus, 3 Icterus 
galbula, 2 Icterus spurius, 2 Tyrannus carolinensis, 1 Empi­
donax trailli, 1 Ooccyzus erythrophthalmus, 1 Melanerpes 
erythrocephal us. 

Elaphrus rusca1·ius: l Turdus migratorius. 
Clivina striatop11,nctata: l Mimus carolinensis. 
Calosoma calidum : l Quiscalus purpureus reneus, 1 Melaner-

pes erythrocephalus. 
Scarites substriatus: l Melanerpes erythrocephalus. 
Chlcenius: l Harporhynchus rufus. 
Anisvdactylits sp.: l Mimus carolinensis, 1 Spiza americana. 
A. baltimorensis : 2 Sialia sialis. 
Stenolophus conJitnctus : l Harporhynchus rufus. 
Staphylinus badipes : l Turdus migratorius. 
Ips fasciatus: l Spiza americana, 1 Oontopus virens. 
Olibrus: l Troglodytes domesticus. 
Hister americanus : l Mimus carolinensis, 1 Harporhynchus 

rufus. 
H. perplexus: l Mimus carolinensis, 1 Harporbynchus rufus. 
Dorcus pm·allelus : l Quiscalus purpureus reneus. 
Canthon hudsonias : l Melanerpes erythrocephalus. 
Ontlwp~iagus : l Mimus carolinensis, l Spizella agrestis, 1 Pas-

senna cyanea. 



The Regulatil:e Action of Bfrd upon Insect Oscillations. 31 

Aplwrhuc c:.]J .: 1 Turdu mi ratoriu 1 Mirnus carolinensis, 1 
Harporhynchu rufu 1 ialia iali 1 Troglodytes domesti­
u , 1 Dendrce a re tiva 1 Dendr ca striata, 1 pizella 

aare ti 3 piza americana 1 Pa erina cyanea 1 Molothrus 
ater ontopu viren 1 Empidonax flaviventris. 

A. inquinatu : 1 Tur lu mi Tatoriu , 1 imus carolinensis, 2 
mpeli e lrorum 1 Petrochelidon lunifron , 1 pizella 

agre ti 1 piza americana 1 Tyrannu carolin nsis, 1 Con­
topu viren . 

A .. f◄ m,omli, : l mpeli drorum. 
D iplotaxic g orgire : l H arporb nchus rufu 
Phylloplwgu : l Turdus migratorius 3 l\Iimus carolinensi . 
Anomola ~ -: l T rannu carolinen is 2 Empidonax trailli, 1 

occvzu er throphthalmus. 
A. lwicola: l Turdu migratoriu . 
~-:L binotatrr : 3 Turdus miaratorius 10 Mimus carolinensis, 2 

H arporb n bu rufu 4 ialia sialis, 1 Vireo gilvus, 2 Spizella 
dom tica piza am ricana, 1 Zamelodia ludoviciana, 4 
Pa erina cyanea, 1 Agelreus phceniceus, 3 Icteru galbula, 2 
Tyrannu arolinen is 1 Empidonax flaviventris, 2 Melaner­
pe erythrocephalu . 

"J.lelanotu': l Turd us migratoriu , 1 Mimus carolinensis 1 Har­
porhyncbu rufu 1 T rannus carolinen is, 1 Melanerpes 
erythrocephal us . 

.J..lfonocr :pidius : 1 Turdus migratoriu 1 Harporbyncbus rufus, 
1 pizella aare ti 1 Pa erina c anea . 

..1.1£. cmritu' : 1 T roglodytes domesticus. 
T eleplwnt bilineatus : 1 H elminthopbaga perearina, 1 Den­

drceca resti va 1 Vireo gilvus. 
P hymatocle variabili : 1 Icteru galbula. 
P senoceru SU] rnotatus : l Parus atricapillus, 2 Troglodytes 

dome ticu , 3 Dendrceca restiva 2 Dendrceca pennsylvanica, 
3 D ndrceca triata, 1 D endrceca virens, 1 Geothlypis trichas, 
1 Icterus galbula 1 Empidonax flaviventris. 

h)·y om la utumli : l ialia sialis, 1 Ortyx virginiana. 
D ialn·oticrt ·ittrttrt : 1 ialia siali . 
D ibolia ai};·e(( : l ~Iolothru ater. 
Gm1 lwrhinu tclosus: 1 Turdus miaratorius, 1 Mimus caro-

linen i . 
T, mymecu,s corifi rtu : 1 Mimus carolinensis, 1 Agelreus phce­

niceu . 
B aris : 1 Mimus carolinen is, 1 pizella domesti a, 1 pizella 

agresti 1 Pa erma cyanea. 



32 The Regulative Action of Birds upon Insect Oscillations. 

B. conjinis: 1 Harporhyncbus rufus. 
Sphenoph.orus : 1 Mimus carolinensis, 1 Spizella agrestis, 1 Spiza 

americana. 
P ,iesma cine1·ect : 1 Geothlypis trichas. 
Blissus leitcopte1·us : 1 Troglodytes domesticus. 
Alydu · eu1·inits : 1 Turdus migratorius. 
Ga3nus deliitS: 1 Turdus migratorius, 1 Mimus carolinensis, 1 

Sialia sialis. 
Hymenarcys: 1 Turdus migratorius, 1 Empidonax flaviventris. 
H. a3qualis : 2 Sialia sialis. 
E itschistits : 1 Sialia sialis, 1 Vireo gilvus. 
P odisus spinosus : 1 Mimus carolinensis. 
Eolydesmus serratus : 1 Turdus migratorius. 
I u lus : 1 Mimus carolinensis, 1 Harporhynchus rufus, 1 Troglo-

dytes domesticus. 
Graw.fish : 1 Quiscalus -purpureus reneus. 
Lumbricus: 1 Turdus migratorius. 
Polyg_on7:rr:, : 1 Molothrus ater, 1 Agelreus phreniceus, 2 Ortyx 

v1rgmiana. 
Wheat : ~ Spiza americana, 1 Agelreus phreniceus. 
Setaria: 1 Coturniculus passerinus, 2 Spizella domestica, 1 Spiza 

americana, 1 Passerina cyanea, 1 Ortyx virginiana. 
Gorn: 1 Molothrus ater, 3 Quiscalus purpureus reneus, 2 

Melanerpes erythrocephalus, 1 Zenaidura carolinensis, 2 
Ortyx virginiana. 

Panicum: 1 Spizella domestica. 



ERRATA. 

Page 6, line 12 from bottom; page 8, line 15; page 11, line 2; 
for Cyclniclce, read Pentatomidce._ 

Page 17, line 9, before Vireo; omit ancl. 

Page 23, above ARACHNIDA, for Cyclnidce, read P entatomiclce. 

Pages 25 and 27, above Orthoptera, for Cyclniclce, read P enta-
tomidce. 

Page 28, lines 2 and 8, for Graphorhinus vados1ts, read Epi-
cce1·us imbrricatus. · 

Page 64, under Hemiptera, for Siplwnophora granarice, read 
Aphis maidis. 

Page 69, line 5 from bottom, for jresh-wate1·, read local. 

Page 78, line 1, after all, insert the. 

Page 82, line 7, for cha1·acte1·, read charctcte1·s. 

Page 91, line 5, for consisted, read consists. 

Page 92, line 2 from bottom, for more, read most. 

Page 97, line 11, for f01·y-six , read f01·ty-six . 

Page 99, line 2, for witn, read with. 

Page 101, lines 12 and 13 from bottom, for stritcture, read 
structitres. 

Page 105, line 23, for aeration, read ae1·cttion .