Bulletin STATE OF ILLINOIS DWIGIIT H. GREE1", Gorc;rrnor DEP ARTMENT OF REGISTRATION AND EDUCATION FRANK G. THOMPSON, Director NATU R AL HISTORY SURVEY DIVISION THEODORE H. FRISON, Chief Volume 22 BULLETIN Article 4 The Prairie Chicken in Illinois R ALPH E. YEATTER (I) . . Printed by Authority of the Statr of Illinois URBANA, ILLINOI S May 19./-3 STATE OF ILLINOIS DWIGIIT JI . GREES, Go'f.•unor DtPAR ntE~T OF REGISTRATION ,\~D EDUCATIO~ FRASK G. Tuo~1rso~, Director BOARD OF ~ATURAL RESOURCES AND CO~SERVATIO~ FRASK G. T110~1rsox, Chairman W ILi.LUi T REI.E AS E, D.Sc., LL.D., Biology ARTHUR CUTTS \VILLARD, D.Eng., LL.D., EZR \ J. KRA US, Ph.D., D.Sc., Forestry President of tlu U11i'f.•ersity of Jlli11ois L. R. ll owsos , B.S.C.E., C.E., E11gineeri11g EDsox S. BAsT1s, Ph.D., Geology R<)GER Ao.u1s, Ph.D., D.Sc., Chemistry NATURAL HISTORY SURVEY DIVISION Urbana, Illinois SCIENTIFIC AND TECHNICAL STAFF THEODORE H. FRISOX, Ph.D., Chief Section of Economic Entomology \\'. P. Fus-T, B.S., Cl1ief Entomologist C. C. Co~IPTOS, Ph.D., Associate Entomol­ ogist ~1. D. FARRAR, Ph.D., Researc/1 Entomolo­ gist J. H. BIGGER, 1\1.S., Associate Entomologist S. C. CIIA!l:DLER, B.S., Southern Field E11to­ mologist J .UIES \\'. ,\l'PLE, 1\1.S., Nori/um Field E11tomologist H. G. BERGER, ~I.A., Assistant Entomologist H. H. PF.TTY, JR., B.A., ,-lssistnnt in Ento­ mology £.~tension C. J. \\'EINM,\~, Ph.D., Special Research Assistant in Entomology \\'1LLL\M H. HASSE, Entomological .-I ssistant Jo11 x ~I. \VRIGIIT, B.A., Junior Entomolo­ gist ( V. S. B. E. P. Q. and Commodity Credit Corporation, cooperating) Section of Insect Survey H. H. Ross, Ph.D., Systematic Entomologist CARL 0. Mo11R, Ph.D., Associate Entomolo­ gist, Artist (on leave ) B. D. BURKS, Ph.D., .-I ssistant Entomologist (on leave ) 1\111.Tos \\'. S,\XDERSOX, Ph.D., Assistant Entomologist KATHRYX 1\1. so~l~IEBIAS, M.S., Artist, Entom ological Assistant Section of Forestry J A~I ES E. DAVIS, M.F., Extension Forester LEE E. YE.\GER, Ph.D., Forester Section of Aquatic Biology DAVID H. THOMPSON, Ph.D., Zoologist GEORGE \V. BENXETT, Ph.D., Limnologist D. F. HASSEN, Ph.D., A ssistanl Zoologist Section of Game Research and Management R. E. YEATTER, Ph.D., Game Specialist Section of Wildlife Experimental Areas ARTHUR S. HAWKINS, M.S., Game Tech­ nician (on leave) F. C. BELLROSE, JR., B.S., Assistant Game Technirian J. ~-. Low, Ph.D., Assistant Game Tecl1- 11u1a11 \V. _H_. ELDER, Ph.D., Assistant Game Tecl1- 111oan Cooperative Wildlife Restoration Pro,!ram (Stale Departme11t of Conservation and V. S. Fish a11d Wildlife Service) OTTO \V. TIEMEIER, M.A., Junior Biologist Section of Applied Botany and Plant Pathology L. R. TEIION, Ph.D., Botanist D. B. CREAGER, Ph.D., Research Pat/10/ogist J. C. CARTER, Ph.D., .4 ssistant Botanist G. H. HOE\H, 1\1.S., Field Botanist Section of Publications JAMES S. AY,\RS, H.S., Tee/mica/ Editor CossULTAXT: Herpetology, HOWARD K. GLOYD, Ph.D., Director of the 11/useum, Chicago .-l rademy of Sciences T hese ~a~ ers are conlribulions from lhe Section of Game Rt:search and iUannte111e11t 011d the Section of Wi/dlifr Experimental Areas. ( 40936-3:\1-3-43) ~2 CO N T ENTS Page EARLY DISTRIBUT ION •...•.. •• .. . ......... • .. . ... ....•... . . . . . .••.• . ........... 377 PRESENT R ANGE .•.. ........................ . .. • ... . .. ...•..............•...•. 379 Lif!x~r~;~~-- ........ :::::::::::::::::::::::::::::::::::: :: ::::::: :::: :: ::: ::: :~~i Booming ............ . . ........................................... . .. . . . .... 386 F locking ... . ........ . ... . . ... . . . .. . .................................. . ..... 387 :\-l ovements .. . .... . ....... ... ... ... . ............ . .......................... 387 Cove r Requirements ........ ... ... ... .. ........... . .......................... 388 Daytime Cover ............ .. .. . . . ... ....... . ............................. 388 Roosting Cover ........... . .... .. .. .. .. ...... . ............................ 388 Nesting Cove r .................... . .... . . ... . . . . . ......................... 389 Red top F ields ......... .. . . ...... . . . .. . . .. . ............................. 389 Fallow F ields and P astures .... ... . . .... ... . ... .. ..... . .................. 389 Waste Grassland ........ . ... .. ........... . . ... .. ... ..... .... . .......... 389 Nesting H a bits ........ . ....... . . . .......... .... . ........ .... .... .. ......... 390 Nest Concentrations .......... . .............. . . . . ...... . . ..... .... . .......... 39 1 Causes of Nest L osses .......................... .... .. ... ..... ..... . ......... 392 Preda tors ..... . .............................. .... .. ... .... ............... 392 D esertion ................. . .................. ..... . ... . .. . ............... 393 Farming O perations .................. . ........ ..... . .. .. .... . .......... . .. 393 Fa ilure to H atch ....................... . ...... ... . ... .... . . .. . ......... . . 393 ,v eights .................... . . . .... . .. . .. . ..... .. . ... .. . . .................. 393 POP ULATION S T UD I ES ......•..•......•......•. ..•.•.•. . •..•. . ..••••........•• . • 393 1\ lORTALITY CAUSES ............ . ...•.•............ .. ..... . .... .•....•......... 396 Juvenile H aza rds ............................ . ... . .. . ....... ..... . .......... 396 Predators ................................... .. . . . . .......... ............... 397 Cooper's H a,vk ............................ .. ..... . ........ . . .. . .......... 397 l\J arsh H a,vk ........................... . . ..... ... . ...... ..... . .......... 397 Buteo H a,vks ........................... . . ...... .. . ... . .. ..... . .......... 398 G rea t H orned O " ·l ........ . ........ . .... .. .. . . ...... ... .................. 398 O ther O " ·ls ..... . ...... . ....... . .... . . . .. ... . ....... .. ................... 398 Red Fox ......... . ....... . .. . .. .... .. .......... . ......................... 399 O ther Predators ............ . . . . .. ... . .... . . .. . ... . ..... . ................. 400 Parasites and Diseases ........ . .... .. ........ ... . .. .. .. .. . .. ................ .400 Accidents . .. .............................. ......... . .. ... .................. 40 1 I llegal Hunting ............................ .... . ....... . . . .................. 401 l\ Iort ality and Populations .................. .. . .. . ....... . . .. ............... .401 F ooD H A BITS ....... .. ... . ...........•.••..... . .. .... .. .........•............. 401 lVl AN AGEI\I ENT ....................•....•. • .•.. •.•.•....•......•......•........ 407 Legal P rotection ............. . .......... ... . ................................ 407 Refuges ........................... . .. ...................................... 408 L easing Land fo r Refuges ... ..... .. .... . .............................. . ...... 409 i:;;'li;~gr ~~::~~(t ·. ·. ·. ·.:::: ::: :::::::: ::: ::::::::::::::::::::::::::::::::::: :1n Trapping and Res tocking ..... .. ....... ....................................... 4 11 Public I nterest .............. . ...... ................................. . .... • .41 3 SU:'\11\IARY ............ . ........ .. ..... ........................................ 413 L ITERATU RE C ITED .•.......... . . . .. ..•......•...... . ......•..•.......•.. ... ... 415 Fem ale prairie chicken entering her ne st , situated in a clump of grasses and dewberries. The Prairie Chicken in Illinois THE g reater prairie chicken , Tym­ pa1111clws cupido america1111s ( Reich­ enbach), was formerly widely dis­ tributed over the grasslands of central North America. Because of its striking appearance, its characteristic breeding be­ havior, and its sporting qualities, it was well known to early generations of Amer­ ican naturalists and sportsmen. In spite of virtual extermination over much of its original range during the past three­ quarters of a century, this bird has persist­ ed in fair numbers in a few favored prairie areas, and it has also extended its range hundreds of miles northward into cutover ,rnodlands and farming sections in a num­ ber of northern states and Canada. The occurrence of widely distributed local areas in which prairie chickens are maintaining themselves with some success has made possible a number of investiga­ tions by game ecologists, chiefly in the Mississippi valley, to discover basic re­ quirements of this game bird and to out­ line measures to conserve and increase its numbers. l\!Iost of these investigations are still in progress. The present report summarizes a study of the biology and management of the greater prairie chicken in Illinois, a study begun in 1935 by members of the Section of Game Research and Management of the Illinois Natural History Survey. The summers of I 935 and 1936 were spent in full-time field work in southeastern Illinois. Since that time, supplemental studies of prairie chicken habits, require­ ments and distribution have been contin­ ued in various parts of the state. An­ nually since I 935, spring and fall censuses have been made on + square miles of prairie chicken range in Jasper County used as a study area. Preliminary para­ site and disease studies conducted br Leigh ( 19+0) were published in anothe·r RALPH E. YEATTER volume of the Survey B11lll'ti11. The pres­ ent report includes data on earlv distribu­ tion, present range, life histor~·, popula­ tions, mortality causes, food l~ahits and management of the prairie chicken in Illinois. The writer of this report is indehted to Dr. \V. Henry Leigh, formerly Assis­ tant Zoologist of the Illinois Natural History Survey, and to Mr. R. E. Hes­ selschwerdt, formerly Junior Biologist of the Survey employed on Federal Aid in Wildlife Restoration Act projects car ried on in cooperation with the l llinois State Department of Conservation and the U. S. Fish and \Vildlife Service; both gave in­ valuable assistance in the field studies in southeastern Illinois. Mr. Harry G. An­ derson, formerly Junior Biologist of the Survey, like Mr. Hesselschwerdt em­ ployed on Federal Aid projects, kindly analyzed the food material found in prairie chicken stomachs. The cooperation of other members of the Survey staff, especially Dr. David H . Thompson, Mr. Arthur S. Hawkins, Dr. Carl 0. Mohr, Dr. Herbert H. Ross, Dr. Leo R. Tehon and Dr. Lee E. Yeager, in various phases of this study is also acknowledged. The Illinois State Department of Conserva­ tion, th rough many of its game wardens, assisted materially in preparing the map, fig. 1, showing the distribution of prairie chickens in the state. The writer \\·ishes to thank the formers in the vicinity of Hunt , Ill., who have allowed him to use their farms for field studies and census work. EARLY DISTRIBUTION Nearly 60 per cent of the state of Illi­ nois was originally grassland. However, the first agricultural settlers arri,·ing early 111 the nineteenth century avoided the [ 377] 378 l1.1. 1:--:01s ~ AT U R,\ L H 1sTORY Su R\"EY B u1.1.ETI !\"' T' ol. 22, A rt . -I- grassland areas and settled in the timber­ lands along the r inrs and st reams. Tree­ less areas \\"ere then belie\"ed to he un­ sui ted to agriculture and, although it \\"as necessa n· to clear the land along the \\"a ter c·uu rses, the soi l there \\"as bet ter drained than was that of the pra ir ies. .:\Iorem·er , along the fo rest margins, game \\"as abundant , and timber and fuel sup­ plies \\"ere close at hand. In t ime. the high producti\"i ty of the grassland soil be­ came apparent, and agricu lture mo\"ed to the prairie. As the Illinois timberl and s \\"ere cleared and put under the plow , prairie chickens extended their range into these areas from the adjacent prai r ies , in which the first settlers had fou nd them. Later, as the prairie sod was broken and grain became common, ch icken populations increased enormously throughout the grasslands. The highest popul ations, resulting from the early de\"elopment of agriculture, seem to ha\"e occurred du ring the l 860's. Favorable conditions created bv inter­ spersion of crop land and unbroke~ prairie were reve rsed, however , as Illinois agri­ culture de,·eloped from the primiti\"e stage, much of it into highly intensive grain farmi ng. T he prairie chicken then began to decline over large areas of its range. Leopold (1 931 ) says of this period: " The prairies of Ill inois, however , which Hatch describes as poo r in 1836, and where Bogard us describes chickens as only 'rather numerous' in 1857 , had in 187-J. just passed their prime as chicken coun­ trr." · The period of 1850 to 1880 was one of rapid agricultural development in Illi­ nois. By 1880, the acreages of all farm land and of improved land in farms were reported greater than at present. 1\'luch of the improved fa rm land , ho\\"ever , did not hecome fully productive until later , when it was art ificially dra ined ( Case & .Myers 193+). .:\Ierritt ( 190+ ) states that game declined markedly in northwestern Illinois during the up tu rn of agriculture immediately following the Ci vil \Var. Prohahly a similar trend held true for much of the state. Undoubtedly heavy hunt ing pressure then and later hastened the decl ine of prairie ch ickens, but a wide­ spread decrease was inev itab le under the practice of intensive grain farming and grazing that was develop ing in the dark soil prairie count ies. T he heyday of the non residen t sportsman and ma rket hunter seems to ha\"e ended d uring this period. O \"e r half a cen tury ago, we find the A 111 aica11 Field ( Aug. 27, 1881) advising its reade rs tha t prairie chicken shooting was no longer good in Illinois or Mis­ souri. Central lllinois \\"as said to have fe w birds. For good shooting, it \\"as necessa ry to go "west of the center of Iowa and .Minnesota." 1 n spite of the decline of prairie chick­ ens, there were still, in the early '80's, occasional records in the hunting journals of fairly large kills in the east central counties of the state. However, on June 9, 1887 , the Illinois State Legislature passed game laws that included a pro­ vision for a closed season on prairie chick­ ens and ruffed grouse during 1887 and 1888, indicating increasing concern over the welfare of these birds. At the beginning of the present century, prairie chickens were still rather generally distributed on the Illinois prairie, but were to be found only locally and in great­ Iv reduced numbers in the dark soil coun­ ties. Under intensive agriculture and drainage, the remaining habitats were be­ ing broken into smaller and smaller units, leaving colonies in only the most favorable localities. In 1903, the season on prairie chickens, then of 30 days , was closed abruptly, and hunting was not again legal­ ized until 1911. Following this action, shortened seasons of 5 to 15 days, with a daily bag limit of three birds, were tried until 1933. Nevertheless, chicken popu­ lations continued to decline. In 1933 the season on prairie chickens was closed and has not since been reopened. About 30 years ago, Forbes ( 1912) reported, on the basis of information re­ ceived from game wardens, that prairie chickens were present in at least 7+ Illi­ nois counties ( nearly twice as many as in I 9+2). Reports received by Forbes in 19 12, and now in the Illinois Natural History Survey files , indicate that prairie chickens were then holding their own or increasing in some of the less adequately drained areas in eastern Illinois, but be­ commg rare in the central part of the state. Leopold's ( I 931) game survey of the north central states disclosed no colonies in the dark soil upland prairie counties May, 19-/.3 YEATTER: PRAIRIE CHICKEN 1:-: J LLl:-.'OIS 379 west of the Illinois Ri ve r , although sev­ eral local colonies were still present in the east central, the northern and the southeastern counties. In these southeast­ ern counties is the main Illinois range of the prairie chicken today. The period 1930 to 1935 saw the dis­ appearance of nearly all of the remaining colonies in the east central counties, and a reduction of birds in the northeastern marshlands. One of the last prairie chick­ en flocks remaining in the central part of the state was on the South Farm of th e University of Illinois at Urbana, where birds were reported present until 1932 by Dr. vV. L. Burlison, Head of the De­ partment of Agronomy of the College of Agriculture. PRESENT RANGE A survey of the range of the prame chicken* in Illinois in 19-1-0, fig. 1, shows t"·o general regions of importance: about 50 square miles of sand prairie along the Green River in Lee County, northwestern Illinois, and approximately 2,600 square miles in the gray soil prairie in the south­ eastern counties. To these regions may be added about 200 square miles of small occupied areas, principally in northern and south central Illinois. The total occupied territory, ap­ proximately 2,850 square miles, represents about 9 per cent of the area of grassland soils in the state, most of which were un­ doubtedly occupied by prairie chickens in the presettlement era. It is evident that prairie chickens ha ve persisted best in areas of the poorer prairie soils where fallow land or special farm­ ing practices provide more favorable en­ vironment than that in the intensively farmed areas. These birds survived longer on the heavy, dark soil of east central Illinois than on the upland prairie west of the Illinois River , probably because the east central area was poorly drained , hence less intensively farmed, until a compara­ tively recent date and was also less in­ tensively grazed by livestock. Apparently the birds disappeared first from th e ac­ quired woodland range and then from the adjacent prairies, their original habitat. *Throughout this paper the term prairie chicken, as it relates to Illinois birds, refers to only the greater prairie chicken, Tympan1uhu s cu_pido americanus (Reichenbach). It is notable that a considerable number of small, scattered colonies, in some cases now only a few dozen birds are to be found in the dark soil counti~s of north­ ern and north central Illinois , where thev have persisted for many rears around mar_shlands or other accid~nt;1lly preserved habitats. However, many such isolated colonies reported hy Leop~ld ( 1931 ) have dis~ppear~d du_ring the past dozen years. \ V1thout intelligent management, it is ex­ trem~ly ~ikely that all of the remaining colornes 111 northern l llinois will eventu­ ally be lost. In southeastern Illinois, the prospects for the surv ival of prairie chick­ ens a re better, al though the outcome there depends chiefly on future agricultural de­ velopments and the conservation policies pursued with respect to these birds. Ni ne major types of farming areas in Illinois are defined by Case & ~lyers ( I 93-1-), fig. 2, who state , "By 'type-of­ farming area' is meant an area in which one or more dominant types of farming can, in most cases, he easily distinguished and within which natural agricultural re­ sources and biological and economic con­ ditions are highly uniform. " Reference to the distribution map, fig. I, and the map showing the major types of farming areas in Illinois, fig. 2, will show that the chief lllinois prairie chicken range lies almost entireI,, in the sou th­ eastern mixed farming ;ection, Area 7, with the largest part of it lying in the central portion, Area 7 b, which is the most important center of redtop seed pro­ duction in the United States. The range extends well into Areas 7 a and 7 c, al­ though red top, A grostis alba Linnaeus, is grown somewhat less extensively and the ratio of prairie soil to woodland type soil is smaller there than in 7 b. Fig. 3 shows typical prairie chicken range in Area 7 b. Area 7 is in the so-called "gray prairie" soi l region of southeastern Illinois, charac­ terized by light-colored silt loams and poorly drained, tig:ht clay subsoils. These soils are of rebtively low productivity and are strongly acid. Because of acidity as well as poor drainage, they are not suited to grm,·ing leguminous hay crops unless heavily limed . Case & l\lyers ( 193-1-) state, "The low yield of grain crops on untreated land in Area 7 and the cost of liming: has led to the replace­ ment of grain crops with redtop, "·hich 3S0 lu.1:--01s i\ATURAI. H 1sTORY Su R\' EY B u1.1.ET 1:-- /' cality in the state is to\\'ard cleaning up fenccro\\'s and thickets. As a result, quail populations ha\'c been red11ced somewhat in the past few ,·cars. The recent increase in the amo11~1t of soyheans grown in this region and low prices for redtop seed have made inroads on the acreage of redtop and idle land. Ho\\'c\'cr, this development docs not at the present time appear to have Fi~. 3.-The type of farm land occupied by prairie chickens in southeastern Illinois. has mainta ined its native wildlife as well as the gray soil prairie region of south­ eastern Illinois. Birds nesting in numbers there in redtop and fallow fields include prairie chickens, quails, upland plovers, marsh hawks, meadowlarks, horned larks, H cnslow's sparrows, field sparrows, grass­ hopper sparro\\·s and several others. On the flat uplands of this region, in addition to numerous usage orange hedges, young pin oak, shingle oak, blackhcrry, raspberry, hazel, panicle dog\\'ood and other cover species arc common in manv fencerows and waste areas. This cover: figs. -t- and 5, in connection \\'ith cultivated grain c rops, rcdtop and fallow fields, makes this area so favorable for quails and rabbits that it attracts hundreds of hunters each fall. \ Vil di ife populations, especially of the brush-inhabiting species, arc of course af­ fected by the amount of idle land and brush present. This varies with economic conditions. The trend under present rela­ tively high prices for agricultural products caused an appreciahle reduction of prairie chicken numbers. Although there can be little doubt that Illinois prairie chickens inhabited cleared woodland soils to a considerable extent during the period of crude agriculture, these birds are at present confined almost entirely to prairie soils. Bennitt's ( 1939) map of the distribution of prairie soils and prairie chickens in :Missouri shows the close relationship of the remaining range to certain types of prairie soils in that state. In southeastern lllinois, where there is extensive interspersion of wood­ land soil areas with the prairie or grass­ land soil areas that harbor prairie chick­ ens, as a rule the only woodland soil farms on \\'hich chickens are found are those that immediately border the prairie. One explanation for the apparent pref­ erence of Illinois prairie chickens for prai­ rie soils may lie in the density and compo­ sition of grass and herbaceous growth, as well as in the type of plant succession, found on the prairie. Visual appraisal of May, 1943 Y EATTER: PRAIRIE CHICKEN TN ILLINOIS 383 Fig. 4.-Cover used by small game in southeastern Jllinois; a growth of young pin oaks, shrubs and berry vines along a stream. typical areas of vegetation on prairie and or. woodland type soils gives the distinct impression that the cover requirements of the prairie chicken are met more adequate­ ly at present by the prairie growth than by vegetation found on woodland type soils. Redtop, for example, on the prairie usually makes somewhat better ground cover than on woodland type soils; the older redtop fields on the prairie develop typical patches of dewberries and herba­ ceous plants that provide favorable nesting places, especially along the margins, while redtop stands on ,rnodland type soils sel- Fig. 5.-Cover used by small game in southeastern lllinois. The dense growth on the left is an osage orange hedge. The larger tree on the right is a shingle oak. 384 ILLIXOIS ,7\ ,\TUR.·\L HISTORY SUR\'EY B ULI.ETI~ f'ol. 22, Ari . ./- dom furni:-h such fa,·orahle combinations of vegetation. The importance of uncultivated areas, especially grassy area:-, in prairie chicken management is stressed by Gross ( I 930), Leopold ( 1931 ). Bennitt & ~agel ( 1937) , Hamerstrom ( 19+1 ). Grange ( 19-tl ), Lehmann ( 19+ l ) and others. Because soils comprising the present major range of the prairie chicken in Illi­ nois are of relati\'ely low agricultural \'alue. the percentage of land that lies id le annually is higher there than in the better portions of the prairie. This un­ cultivated land. "·hich furnishes a certain amount of cowr and food, must be re­ garded as a contributing. but secondary, factor in the successful stand of prairie chickens in southeastern llI inois , since these birds are maintaining themscl\'es in fair numbers in certain redtop-producing localities where there is practically no idle land. During the present study it became in­ creasingly apparent that the redtop crop grown in a dozen counties in southeastern Illinois \\·as admirably adapted to meet the cover and space requirements of prairie chickens at various times of the year. in­ cluding the period of the elaborate court­ ship performance. Of paramount impor­ tance is the fact that harvesting of the redtop crop is not begun until approxi­ mately July l or July I 5, depending on \\"hether the redtop is grown for hay or seed. Because of the lateness of the har­ vest, redtop proYides a habitat somewhat li ke the native prairie during the critical nesting period and while the hirds are \'cry young. Contran- to the common belief that prairie chickens will thri\'e onh- where tracts of wild lands remain, in s~utheast­ ern lllinois these birds are found in fields close to farm buildi ngs. where they are in frequent contact with domestic turkc,·s and chickt:ns, thus providi ng notewortl;y e\·idence of a potential adaptability to !'.'>t:ttled communities. Although, in some instances, prairie chickens ha,·e persisted for long periods in dark soil prairie districts, where up to 85 per cent of all farm land is plowed annually, their rate of reproduction in most districts of this type has been too low to prevent their ultimate disappear­ ance. The farming practices now widely employed in dark soil prairie regions do not provide the habitats essential to prairie chickens, and, unless conditions change mar kedly, the less fertile prairie soils will continue to be the chief range of these birds in Illinois. LIFE HISTORY The life history of the prairie chicken has heen studied in detail hy seYeral work­ ers whose observations ar~ acknowledged below. ~Jany of the findings of these \\·orkers have been verified by field work, principally on the Jasper County study area in southeastern Illinois, which has yielded new as well as supplementary in­ formation. Sexual Cycle In southeastern Illinois, male prame chickens, while still in winter flocks, may show the first evidence of the mating dis­ plar during mild \\·eather as early as late Fig. 6.-;\,]ale prairie chicken at the climax of the booming performance. J anuarr or the first few days of February. At first this activity consists of fighting, strutting and loud cackling-, but a few days later the first characteristic booming, fig. 6, may be heard from the booming grounds. The earliest date booming has been heard hy the writer is January 30, in I 939. For se\'eral weeks after the first males appear on the booming grounds, flocks of chickens, consisting apparently of both fe­ males and those males that have not yet .1.lf ny, 19-13 YEATTER: PRAIRIE CttlCKEX I~ I LLIXOIS 3S5 ?egun to display, are commonly seen stay­ mg close to the booming grounds. On March 1, I 939, apparently less than IO per cent of the total prairie chicken popu­ lation of the Jasper County study area ":ere 1!1ales in which the boomi,{g and d1splaymg performance was fully devel­ oped. I~ an inte1:s!ve study of the breeding habits of prame chickens in \ Visconsin , If) w I u I- < I I,... 0 a: w en :::E ::) z 20 15 10 s 2 /. 8 5 D [J 4 DATA fROM NESTS DATA FROM YOUNG BROODS I ,3, 0 '-'-"-'-----'......J.-J,_J,__1_...l...-L....L ___ .Ll,_l.J 1-15 16-31 1-15 16-31 1-15 16-31 1-15 MAY JUNE JULY AUG. DATE OF HATCH Fig. ?.-Hatching period of prairie chickens on the Jasper County study area, chiefly in 1935 and 1936. Some of the hatching dates were obtained from nest observations and others were calculated from careful estimates of the ages of young broods encountered in the fielTAI. -;,:F. ST ll'.(; ;\ lMnF.R P ER C F.:--T l\ ·rt: o r Cm·ER Co,·ER os STl'I>Y O F :'.\' ESTS S t·ccF.ssr 11L :\REA Rcdtop . .. . . . ... 60 14 57 Id le hdds and past ures ......... ' 36 12 33 \\'astc ~rassla nd . . . . . . .. . ... 4 13 54 Tora.I . . . . . . . . . . ..... . . . . . 100 39 49 -- -- - con.' r from booming grou nd:- also appa r­ r nth· influences the choice. J{efcrence to table 1 shows that , in this stuch·, success of nests in redtop fields and in ,~·aste areas was h igher than in idle fields. Although no concl usions can he drawn from the few records presented here, there is some basis for believing that nest losses in idle fi elds a re often rela­ tively high, d ue to the fac t that these areas freque n tly are plowed after nesting has begun. .:\lo reover, losses resulting from predators a re apparently higher in fallow fields than in red top because the former mo re frequently contain dens of furhear­ ers whose early spring hunting activities include nearby open areas. Nesting Habits As indicated above , prairie chicken nests in southeastern Illinois are located usualh· in grassy sites, sometimes without an;• other vegetation for cover, hut more often Fi~ 10.-Fernale prairie ch icken incuha ting her egg:; in a nest partly concealed by a growth of i ronweed s. ,Hay, 19./-3 YEATTER: PRAIRCE CHICKEN I~ ILLINOIS 391 with a bramble or a few herbaceous plants serving as overhead cover, frontispiece and fig. 10. Some nests are in thin growths of grass under a single stem of dewberry or rose that offers scant concealment, Nine of 23 prairie chicken nests repor t­ ed on by Hamerstrorn (1939) in \Viscon­ sin were within a half mile of a booming ground, and IO were between a half mile and a mile and a quarter. The distances Fig. 11.-Prairie chicken nest containing 10 eggs. The overhead canopy of bluegrass and dewberries was removed whil e the nest was being photographed. while others have heen found in the thick grass growth of old stack bottoms in red­ top fields. Tall and rank weed growth apparently is not attractive to prairie chickens. There appears to be a definite tendency for field nests to be situated within a few feet from the field margins. Not infre­ quently nests are found close to hedges or small trees along field margins or streams. Gross (1930), working in \Visconsi n, found that on rare occasions nests are sur­ rounded b,· trees of considerable size. Prairie ~hicken females occasionally lay eggs in the nests of others of their kind , making up clutches of 20 or more eggs. The largest observed clutch believed to have been laid by one prairie chicken con­ sisted of 16 eggs. The avera ge size of 12 clutches, most of them seen in 1935 and 1936, and each clutch laid apparentl y by a single female , was 12.3 eggs. Fig. 11 shows a nest containing 10 eggs. from the other -J. to th e nearest booming ground were unknown. In southeastern lllinois, where booming grounds are ap­ parently much closer together than in the area in which Hamerstrom worked, the re­ lationship of outlying nests is difficult to determine, but a definite tendency for nests to be grouped close to booming grounds was evident. The great majority of nests found on the Jasper County study area were within a radius of a quarter mile from the nearest booming ground; and wherever favorable nest sites were avail­ able on the Jasper County area a number of nests were found between 150 rards and 330 yards from a booming grou~d. Nest Concen trations Reports received from observers \\·ho recall conditions in southeastern l llinois 60 ,·ears or more ago indicate that large nun~hers of prairie chicken nests were 392 ILLl~OIS , . ATURAL HISTORY SUR\'EY BULLETIN Vol. 22, Art . ./- :-onH·t ime:- found in relati,·eh· small areas ot nestinl,!; coHr. Leopold ( 1933) men­ tions reports of former concentrat ions of nt.•sts in I o\\"a. Johnson ( 193-t) recalls a tract of about IO acrl'S of unbroken prairie near his home in ~Ia rshall Coun­ t\, :\ I inn., where numerous prairie chick­ e·n nests, both old and new, were disclosed by a spring fire. These instances seem to be associated with fairly high popula­ tions and the occurrence of areas of choice nesting cm·er in localities in which much of the nesting cover had deteriorated as the result of agricultural practices. Nev­ nthcless, in view of the observed prefer­ ence of prairie chickens for certain ngeta­ tive types, it does not seem unlikely that nest concentra tions mar sometimes have occurred on the ,·irgin ·prairie. Al though the re was ordinarily no marked tendency for nests to he grouped together on the Jasper County study area, in at least one instance favorable nesting co,·er was responsible for the selection of a number of nesting sites within a limited area. In 1936 a booming ground used by about 7 males was located slightly more than an eighth mile from a small area of grasslan d, the margins of which were being invaded b,· blackberries. This tract, about 200 yard; long and less than 100 yards wide, approximately -t acres, included part of a lightly grazed pasture, a small fallow area and a strip of bluegrass along a creek. A sea rch of this cover in June revealed four prairie chicken nests. Since no other nests \\"ere found nearby, it seems probable that nearly all , if not all, of the females in that locality were nesting in this small area. By ~1 ay 1, in Jasper County, red­ top has usually made sufficient growth to invite nesting, and after this there is prob­ ably less tendency for nests to be grouped in small bluegrass areas. Causes of Nest Losses Although of 39 nests under observation in Jasper County, 19, or +9 per cent, were successful. table I, it is significant that of the 20 unsuccessfu l nests 7 were aban­ doned or destroyed early in the season when only one to three eggs had been laid. There is considerable reason to be­ lieve that in such cases new nests are begun within a few davs. Indications are that in southeastern (llinois a compara- ti,·cly high percentage of the females final­ ly bring off broods successfully, because of renestings and a general increase of the quality and quantity of nesting cover as the breeding season advances. It is of interest to note in this connec­ tion that, although field studies in I 935 and 1936 showed an occasional attempted renesting as late as July, there was no evi­ dence that nesting attempts begun after the first week in June added a significant number of young birds to the crop. Ap­ parently red top cutting during July finds the hatching period nearly over and most of the nesting attempts ended, fig. 7. The causes of 19 out of 20 nest failures were known or could he determined from evidence at the nest. Predators destroyed se,·en nests, desertion was responsible for the loss of six, farming operations de­ stroyed five, one full clutch was apparent­ Iv infertile and one nest from which three ~r four eggs had disappeared was listed as failing for an undetermined cause. Predntors.-Clutches laid in April in poor cover were found to suffer fairly high losses from crows and furbearers. Thirty-five per cent of the nest losses ob­ served in this study were due to predators. In addition, broken shells, showing beak or teeth marks, were frequently found on the ground, and the nests from which they had come could not be located. Egg shells were sometimes found along hedges where they had apparently been dropped by crows. In southeastern Illinois, possi­ bly crows take rnore eggs than any other one species, but, since prairie chickens fre­ quently lay an egg or two in exposed places early in the season, it is difficult to say how much of the crows' activity is actual nest robbing. Furbearers hunting widely over mead­ ows and crayfish flats in early spring destroy a number of exposed nests. Ap­ parently, skunh, opossums and, on occa­ sion, minks and raccoons are guilty of nest robbing. The role of snakes as nest robbers in 1 this region is undetermined, hut probably certain species take some toll. In southeastern Illinois, growth of vege­ tation by early May usually restricts the feeding areas of most predatory species, and, as a result, nest losses from predators become of minor importance. Under these circumstances, the effect of egg predation ,l/ay , 19./-3 YEATTER: PRAIRIE CHICKEN 11' ILLJNOIS 393 seems to be chiefly to delay the nesting season. Desertion.-N est desertions in the Jasper County study area occurred chiefly early in the nesting season, and usually when only a small number of eggs had been laid. Apparently at the beginning of their nesting efforts the females are \'erv warv and desert as the result of even slight disturbances. Later, when the incu­ bation period is well under way, they do not desert their nests readilv when dis- turbed. - Farming Operations.-Plowing of grass or idle fields in May and June for corn or soybeans is the chief nest hazard to 1 llinois prairie chickens from agricul­ ture. However, spring burning of idle fields in 1936 was known to destroy J as­ per County quail nests and doubtless was responsible for considerable loss of prairie chicken nests. Fortunately, burning has not been widespread since that year, when a large acreage of idle land " ·as put back into cultivation. Failure to Hatch.-Romanoff , Bump & Holm ( 1938) state that fertility of eggs of upland game birds depends on the con­ ditions of mating, the health and activity of male and female birds, and upon several other physiological and environmental fac­ tors. These authors point out also that the hatchability of fertilized eggs is de­ pendent on their inherent vitality and nutrition and the environmental condi­ tions of incubation. They found experi­ mentally that the critical stages during which death of the embryos of pheasants, grouse and quails occurs most frequently are the fourth, the twelfth and about the twenty-second days of incubation. Field evidence as to the fertility of prai­ rie chicken eggs, the mortality of embryos and the effect of environmental conditions on the hatching of eggs is limited because of the relativelv small number of nests observed. Onh; one clutch that was ap­ parently incub~ted normally failed entire­ ly to hatch, in this case seemingly because of lack of fertilization of the eggs. In two clutches nearly ready to hatch , known to have heen exposed for several hours dur­ ing periods of high air temperature and low humidity in each case, the majority of the young failed to emerge from the shell probably because of drying of the egg membranes. In 12 clutches judged to have. undergone normal incubation, ap­ proximately 93 per cent of the l +8 eggs hatched. Weights \ Vhile trapping prairie chickens in southeastern Illinois in January, 19-W, Robert E. Hesselschwerdt, then employed hy the Illinois Natural H iston· Sun·ev on Federal Aid in \Vildlife R~storatio;1 Act projects, and Lynn H. Hutchens, then of the Forest Presern District of Cook County, obtained the weights of 27 live, adult birds. The prairie chickens were in good condition, hut some of them had been held in the traps for 10 or 12 hours before being weighed and had un­ doubtedly lost a few ounces. The live weights obtained hy Hessel­ schwerd t and Hutchens are as follows: average weight of males ( 20 specimens), 2 pounds +.7 ounces; heaviest male, 2 pounds 13.6 ounces; lightest male, I pound 15.2 ounces; average weight of females ( 7 specimens), 1 pound 12.5 ounces; heaviest female, I pound 15.2 ounces; lightest fe­ male, l pound 6..+ ounces. POPULATION STUDIES It was recognized at the outset of the present study that knowledge of at least the gross aspects of the behavior of prairie chicken populations in Illinois was neces­ sary in order to outline an adequate man­ ag~ment program. This recognition led to the collection of a large numher of pop­ ulation records, including field notes and reports received from qualified observers in different parts of the Illinois prairie chicken range. In addition, fall, win ter and spring censuses of the hi rds on the 2,560-acre study area in Jasper County were conducted each rear fro111 autumn of 1935 through the s1\ring of 19-t2. Prairie chicken population trends in northern Illinois are discussed else\\·here in this report. This section deals with the behavior of chicken populations in the principal range in southeastern Illinois. Although censusing of the study area during three different seasons yielded use­ ful information on monments and popu­ lation densities of prairie chickens, it he­ came evident that the fall and winter censuses were less reliable as indices of 394 ILLIXOIS ;\ATUR.-\L HISTORY U R\ EY B ULL ETIX I' ol. 22 .. ht. -I popubtion tr<.'nils th:111 the booming J.!fOllrHl l.'ensuses taken in April. For ex­ ampll', the stud) area 1um·ed to he a fa­ \"orite wintering ground for p rairie chick­ ens and each rear, in earlr \\"inter, an inf1~1x of bird~ occurred ·from nearby farms, causing the population le\"Cl there to rise abo,·e that of the surrounding range. In autumn the relatively high mo­ hilit,· of d1il.'ken flocks caused some , ·a ria­ tion · from dar to dar in the number of birds present ~lll a giv.en area of farmland, II) 140 131 i.J ...J < ~ c., 100 z ~ 0 0 m It.. 60 0 511 a: i.J m ~ 20 :::> z 1936 1937 1938 1939 1940 1941 1942 Fig. 12.-Trend of male prairie chicken popula tion s on a 2-by-2-mile area in Jasper Cou111y, 1936- 194-2, shown hy booming ground cen~uses. although the figures obtained during the fall censu ses were undouhtedh· more near­ ly representative of normal· populations than those from the winter censuses. The fall censuses, taken annually from 1935 through I 9-t-l, usually in late October or early ~o\"ember, sho\\"ed an average popu­ lation during the 7-year period of I 79 hirds present on the area. The largest number of birds sho\\"n by any fall census \\"as 255, in I 938, and the smallest num­ ber was J-t. 1, in 1939. These figures represent a variation in fall population densities of from about J bird per 10 acres to 1 bird per I 8 acres. The average "·as approximately I bird per H.3 acres. The results of the censuses of male birds on the booming grounds of the Jas­ per Countr stud,· area are shown in an accompanying gr~ph, fig. 12. Since the number of males on any par­ ticular booming ground is neve r constant throughout the season, eve ry effort was made to take the census at the height of the booming season, usually in late April. Hamerstrom 's ( 19{1) work clearlr shows the need for care in this respect. The booming census is subject to criticism in that it does not include the female hi rJs; our efforts to determine sex ratios by trap­ ping in late \\·inter were unsuccessful due to the fact that a disproportionatclr large number of males were found to enter the traps. .:'\ enrthcless, field experience indi­ cates that the census of booming males provides a usable and reasonablr accurate index of local prairie chicken p~pulations. Davison ( I 9-t-0) used the booming ground census extensiHly in connection with his study of the lesser prairie chicken, T_r111pa1111clws pallidici11ct11s (Ridgway), in Oklahoma. By comparing results ob­ tained on census areas of different sizes, he concluded that the minimum area that could be censused as representati\"e of anr locality is 2 by 2 miles, and that censu·s figures from areas 3 by 3 or -+ by -+ miles are more dependable. The Jasper County census area, 2 by 2 miles, represents the smallest unit indi­ cated by Davison's study as representati.\"e. The census was begun there in 1935 to determine population trends in an area for which weather records and field studies on subjects related to the welfare of prairie chickens were available. Since the dis­ tribution of these birds is spotty in the mixed prairie and woodland districts of southeastern Illinois, it seemed advisable to confine the census to a relativeh· small area lying within the better rang~. It is of interest to note that there was considerable similarity between the popu­ lation fluctuations on the studr area as shown by booming ground ce,{suses and the fluctuations indicated by field records and reports from other parts of the south­ eastern Illinois range. For example, a de­ crease in the fall of 1936, corresponding to that indicated hr the I 937 booming ground census of th~ Jasper County area, was reported to the writer by a number of observers throughout southeastern Illi­ nois. In :\'lissouri, Bennitt (1939) re­ ported a decrease of prai ric chickens in I 936. The "high'' of 1938 was amply confirmed for other localities in south­ eastern l llinois, as well as the study area, by field observations, by reports recei,·ed from farmers and hunters, and by subse­ quent agitation for an open season. The May, 19+3 YEATTER: PRAIRIE CHICKEN IN I1.uxo1s 395 population decline of 1939, shown hy the I 9-l-O booming ground census, was marked by the absence in the fall of I 939 of the n·umerous large flocks seen in various parts of southeastern Illinois during the previ­ ous fall and winter. Surprisingly, on the study area, where the booming ground census of the spring of 1939 had shom1 I 3 I male birds present, the census taken the following fall showed a total of only HI birds of both sexes. Al though the foregoing records indicate considerable variation in prairie chicken populations from year to year, when several consecu­ tive seasons are considered there is no indication of recent major changes in the average density of these populations in the main parts of the range in southeast­ ern l llinois. Undoubtedly, in recent years, there has been an increase in the total number of prairie chickens in this region, but this is due to extensions of the range into unoccupied territory rather than to building up of local populations. Prairie chickens have been found to un­ dergo cyclic fluctuations over a wide area in their acquired range in the northern Lake States (Leopold 1933) , but relative­ ly little evidence has been published on the subject of cycles in the Central States. Bennitt (1939) states that the type of population fluctuation of prairie chickens in Missouri is uncertain; it seems doubt­ ful to him if Missouri birds are cyclic. Leopold ( 1931) cites a record of high chicken populations in Crawford County, southeastern Illinois, about 1920, but else­ where in the same publication he states: "The question of early cycles must be left unanswered for Iowa, Minnesota, and Illinois. In Indiana, while the early be­ havior is unknown, there is a clear and convincing record of one fluctuation which I have called the 'comeback of 1912.' " That the increase of prairie chickens re­ ported in Indiana in 19 I 2 extended into Illinois is indicated by the following quo­ tation from For bes ( 1912) : " ... prairie­ hens-thanks to our protective laws-are now to be seen in at least seventy-four counties, so abundantly in some that farm­ ers are beginning to protest against their further increase because of the amount of grain which they devour." As previously mentioned, this gain proved to be a tem­ porary one. The average length of cycle of the prai- rie chicken and other grouse in the north­ ern tier of states and Canada is belienporting on the prog­ ress of a grouse investigation in central \Visconsin, tentativelr concluded that ".i\larsh Hawks are p~obahly a consistent but small factor in the mortality of young 398 I Lu:-:01s ~ATLRAL H ISTO RY Su RV F. Y B uLLETl:-: l" ol. 22, Art . .f. J.!rouse in ou r area.'' H e pointed out that destruction of striped spermophiles and other potential enemies of p rairie grouse hr marsh hawks may counterbalance the harm done in preying on the you ng birds. Leigh ( 1939) summarizes h is records of the food brought to a fami ly of young marsh hawks und er observation in the Jasper Coun ty study area as follows : During the period of ohservat ion , young ( unidentified) song hirds, immature rahhits and meadow mice (.1.l/ icro lus ) constituted the major portion of the hi ll-of- fare for the young raptors. Recognizahle bird remains included three you ng Ba h-white and two young Upland Plovers ( Barlramia lo11gi­ cawla). As far as could he determined from feathers, pe ll ets, a nd other fragments , no Prairie Chickens w e re hrought into the young during the ohservation period. Although the ma rsh ha"·k may occa­ sionally take a young prairie chicken, our observations on the summer feeding habits of this hawk in southeastern Illinois pro­ vide no evidence th at it can capture pre\' as large as an adult prairie chicken , unle;s the chicken is crippl ed or otherwise inca­ paci tated. If cont rol of the marsh hawk is indi­ cated on game management areas or ref­ uges for the benefit of game birds, it should be restricted to individuals that a re known to be doing harm. l\!IcAtee ( 1935 ) smns up the economic status of the marsh hawk on the basis of 601 stom­ achs examined by the U . S. Bureau of Biological Survey as follows : P robahly the insect food of the marsh hawk may be balanced against that portion composed of the moderately beneficial snakes and frogs. The remainder of its subsistence is about equally divided between birds and mammals, the indication heing that more harm than good is done in the destruction of the forme r and that the reverse is true in t he case of the latter. The economic tendencies of the marsh hawk seem to he ahout evenly halanced, and the decision as to whether it shou ld he inter­ fered with should he hased on local expe­ rience-hut this should he actu al ex pe rience or ohservation, not prejudice. /J 11 /eo H aw ks.- These large, soa ring hawks, or "mouse hawks," Buteo spp., are relatively unimportant as enemies of prai­ rie chickens. Although the red-tailed hawk may now and then manage to capture full grown pra ir ie chickens on the ground , it is too slow to overtake these birds when the\' are in flight . The red-tail feeds to som~ extent on such potential enemies of game birds as ground squirrels, barn rats, crows and bull snakes, thereby probably compen­ sating fo r occasional destruction of game. The bulk of its food consists of rodents. Red-shouldered hawks and rough-leg­ ged hawks rarely molest heal thy game birds and may be useful on game areas because they tend to keep rodent popula­ tions in check and occasion all\' take weak or diseased game animals o; birds that might ser\'e as sources of infection. Great H onzed Owl.- The great horned owl, Bubo 'l 1irgi11ia11us y•irginianus ( Gmelin), a large and powerful predator, is usually regarded as a serious enemr of small game. Exhaustive studies by Er­ rington, Hamerstrom & Hamerstrom ( 19-J-O) on food habits of this owl in Iowa and \Visconsin show that rabbits and hares are the staple items in the diet of this predator. It regularly eats smaller rodents, chiefly mice and rats , according to these authors. Passerine birds, poultry and game birds make up only a minor part of the total diet. l nstances of conspicuous local predation on game birds are usuallr associated with environments overpopulat­ ed by the game species. In southern Illinois, horned owls in­ habit chiefly the more heavily wooded sec­ tions where prairie chickens are not plenti­ ful. Consequently, predation seems for the most part to be confined to areas where woodland and prairie are well inter­ spersed. Even there our evidence against this owl does not indicate serious preda­ tion on game birds. Stoddard ( 1931) regards the great horned owl as beneficial on quail preserves in the southeastern United States because of the assistance it gives in keeping skunks, opossums, cotton rats and other enemies of the bobwhite within bounds. On refuges or game management areas, particularly in the northern part of Illi­ nois, elimination of individual horned owls may in some cases be necessary to protect concentrations of game birds, but a systematic campaign to eradicate these predators from prairie chicken refuges is not recommended. Other Owls.-Although the northern May, W/.3 YEATTER: PRAIRIE CHICKEN IX ILLINOIS 399 barred owl, Strix 'l 1aria 'i.'aria Barton, ap­ proaches the horned owl in size, it feeds to a greater extent on mice and is less prone to take poultry or game birds. This owl is generally more common than the horned owl in the southern Illinois prairie chicken range. It sometimes hunts in the daytime and is the large owl most fre­ quently shot by hunters. On the basis of intensive food studies, as ·well as field observations in Illinois, killing of these birds is not to be recommended except in the case of individuals that may form the habit of taking poultry or game birds. Throughout the prairie region of Illi­ nois, the short-eared owl, d sio f{am/1/eus f{alll///e11s ( Pontoppidan) , is encountered by hunters probably more often than any similar bird because of its habit of resting during the daytime , singly or in small groups, in weedy areas or stubble fields. Short-eared owls are attracted to fields in which mice are abundant, where they sometimes hunt by day. Their pellets usu­ ally contain little besides mouse fur and bo~es. These birds rarely nest as far south as south central Illinois; throughout the state they occur mainly as winter resi­ dents. Smaller than northern barred owls, they are not known to take game birds larger than a bobwhite or a Hungarian partridge, and these only rarely. The short-eared owl, the barn owl, Tyto alba prati11cola (Bonaparte), and the long­ eared owl, d sio 'loilso11ia1111s (Lesson), are highly beneficial to the farmer and should be fully protected. Red Fox.-In recent years, the popu­ lation trend of the red fox, Vulpes ful'l•a ( Desmarest) , in the state has been gen­ erally upward. At present, red foxes can be classed as abundant throughout the prairie chicken range of southern Illinois. According to distribution studies made by Dr. Carl 0. Mohr of the Illinois Natural History Survey, and based on trappers' records, the red fox population of the gray soil prairie region is somewhat higher than the average for the "·hole state. Although no special study of fox food "·as attempted, field records obtained in southeastern Illinois during all seasons throughout a period of 7 years did not indicate that the red fox was particularly destructive to game birds in that region. Errington's (1937) conclusion that pheasants, bobwhites and Hungarian part- ridges in Iowa are subject to a temporary increase in vulnerability to general preda­ tion at the beginning of the mating and breeding season is in agreement with our observations on prairie chickens. Never­ theless, prairie chicken losses at this season did not reach serious proportions in the Illinois area studied. Al though some of the six instances of apparent desertion of nests listed in the section on nesting may possibly have been due to death of the female, it is of interest to note that no instance of killing or in­ jury of a female directly on the nest by a predator was evident in the 39 nests under observation. Probablv reduced emission of scent during the inc~bation period, which occurs in the prairie chicken and certain other gallinaceous birds, is in part respon­ sible for the relative safety of the nesting female. However, this affords only partial protection, as indicated by the fact that killing of the female on the nest hy house cats or other mammalian predators is re­ ported in the bobwhite ( Stoddard 1931) and the Hungarian partridge (Yeatter 193-t). Errington ( 1937) says of the fall. win­ ter and early spring feeding of the red fox in Iowa: During fall and winter, the brunt of red fox feeding pressure is borne hy mammals, notably mice and rahhits. Occasional pas­ serine birds, ring-necked pheasants, and bob­ whites are taken, and these and other spe­ cies are freely eaten as carrion when car­ casses are found in fields or along highways. Domestic chickens eaten are probably carrion for the most part at this season; many farmers habitually dispose of their dead chickens by throwing them on the manure spreader, and the carcasses thus be­ come available to various creatures, includ­ ing foxes. It often happens that foxes bite off and swallow only the heads or feet of carcasses of this sort that they may discover. \Vith the coming of spring and the pupping season mice and rabhits continue to be the main ~taple foods, hut other forms receive more attention, apparent!}' in proportion to their increased availability. l\Iigratory spar­ rows, blackbirds, meadowlarks, etc., yield some toll; and ground squirrels are cap­ tured as they leave hibernation for the dangers of active life. Examination uf fragments and feathers around fox dens, of fox scats and of vari­ ous "kills" of game birds found in the l 1.1.1:-..01s ,:\ ,\TURAL HtsTORY SuR\'EY But.LETI:-..- /'ol. 22, ,/rt . .J. licltl cluri nl! the inn.·stigation gan· rcla­ ti n ·h · few indications of fox predation on prai;ie chickens among se,·eral hundred items of food. ~en·rtheless, experience ma,· sho\\' that control of fox populations is desi rah le on refuges or game manage­ ment areas where speci,d effo rts are being made to conscn·e and increase prai ric chickens or other game hirds. The com­ pa rati,·e abundance of both chickens and foxes in southeastern Illinois, ho\\'e\'er, is good c,·idencc that the fox does not con­ stitute a serious menace to these birds Ill good chicken habitats. Other Predators.-Evidence is mounti ng from \'arious studies that ground squirrels may be important as de­ stroyers of game bird nests as well as their young. Grange ( 19..J. l) , working in \ Vis­ consin, repor ts se\'eral instances of capture and killing of \'ery young domestic chick­ ens hy the 13-striped ground squirrel, Ci­ trllus tridun11/i11N1t11s ( :\Iitchill). Near Urbana, Ill., in the summer of 19..J.2, we found good evidence of the destruction of se\'eral pheasant nests hy the Franklin's grou nd squirrel, C. franklinii (Sabine). Ground squirrels are much more common in the dark soil prairie districts than in the gray soil prairie and their control may present special problems on refuges in the northern part of the state. Since the cro\\·, Con•us brachyrhynclws bracl,yrhynclws Brehm, is known on oc­ casions to he destructive to young prairie chickens as well as eggs, large numbers of this hird on refuges during the nesting season would normallr he undesirable. P ilot black snak~s, common black snakes, hull snakes, and possibly certain other snakes, are potential predators on the young an d eggs of prairie chickens, hut, as these forms feed extensively on rodents, their con trol should not he under­ taken unless they prove actually harmful on reful,!CS. The pilot black snake, f;/aplu obsr,/rta obsoleta (Say), whose food was investigated by Uhler, Cottam & Clarke ( 1939), is fairly common in Illinois , and the common hlack snake, Coluber constric­ /rJr m11strictor ( Linnaeus), which was found by Stoddard ( 1931) to rob quail nests in Georgia, is present in the prairies of southeastern l llinois. On the basis of the aho\'e studies, these fo rms might he expected to take some eggs or young of prairie chickens. The bull snake , Pitu- op his sari rn,ri (Schlegel). \\'hich is known from studies conducted hr the Illinois ~atural History Sur\'ey to. take the eggs or young of waterfowl on occasions, is not numerous on the prairie, but might possibly cause minor losses of eggs or young of prairie chickens in the \'icinity of wooded areas. Domestic cats and dogs have often been reported as causing loss of eggs and young of game birds. Although no instance of predation on prairie chickens hy either cats or dogs was found in the present study, it is not unlikely that in south­ eastern Illinois both animals, particularly field-hunting cats, annually destroy a number of nests and young of prairie chickens. Parasites and Diseases Appraisal of the role of diseases and parasites in wildlife mortality is a diffi­ cult matter. Verr weak animals often secrete themselves· in thick cover where they are likely to be found, if at all, only some time after death has occurred; if partially disabled, they may he caught hy predators and the evidence thus destroyed. Nevertheless, mounting evidence from field studies indicates that pathological factors mar be responsible for greater losses of wildlife than has generally been supposed. Since the prairie chicken is closely asso­ ciated with domestic chickens and turkers throughout its range in southeastern Ilii­ nois, the possible effect of poultry diseases and parasites on prairie chickens was con­ sidered an important part of the investi­ gation. Gross ( 1930) reports that certain poultry parasites and blackhead, a disease fatal to domestic turkeys, were found in the prairie chicken in \ Visconsin and in its close relative, the heath hen, Ty111pa1111- c/111s rnpido rnpido (Linnaeus), in Massa­ chusetts. During the Illinois investigation, a single prairie chicken showing the clinical symptoms of blackhead was found ( Leigh 19..J.0). This bird, an adult male, was extremely emaciated, and died soon after being captured. Although field studies in 1935 and 1936 did not give evidence of serious losses from pathological causes among adult birds, the finding of some unmutilated ,11 ay, 19-1-3 YEATTER: PRAIRIE Caro:.Ex I N ILu:--:01s 401 but partly decomposed carcasses of young birds during both years was considered as of possible significance from the stand­ point of pathology. Previously, Leopold ( I 931) published a report of similar find­ ings by an observer in ~1issouri, and Bennitt & Nagel (1937) quoted game wardens and other observers, also in ~Iis-• souri, as finding dead young during the drought summer of I 93+. In a study of the parasites of llli"nois prairie chickens, Leigh ( 19+0) autopsied 1-t young and 1-t adult birds collected during field work in southeastern Illinois. Blood smears showed no indication of blood parasites. Smears of intestinal and caecal scrapings ,vere negative for coccidia or other protozoa. Internal parasites reported by Leigh included three species of tapeworms, two species of roundworms and one species of Acanthocephala. l t is of interest to note that, although no tapeworms were found in the adult chickens, IO of the I+ young birds were infested with tapeworms, which, in four cases, completely occluded the 1 umen of the small intestine for most of its length. Since the most intense in­ festations were by an apparently rare and hitherto undescribed species of tapeworm , there seems to be little relationship be­ tween parasitism and the presence of do­ mestic poultry. \Vith respect to the possible effect of these parasites on the survival of juvenile birds, Leigh states: Although it cannot be definitely stated at this time that the high incidence and heavy infestations with cestodes of a genus kno,vn to be pathogenic for other gallinaceous birds constitute a serious mortality factor in young prairie chickens, it is reasonable to think that the minimum effect of such in­ tense parasitism in birds 4 to 8 weeks old would be a reduction in vitality which would open the way to secondary infections and render the birds more susceptible to predation or unfavorable environmental fac­ tors. Finding no cestodes in adult hosts would seem to indicate that the prairie chicken is susceptible to the new species of Raillietina during only the first few weeks of life. Accidents Accidents, chiefly those in which the birds strike ,vires or other objects while in flight, not infrequenth· cause the death or q-rippling of prairie chickens. The ex­ tent of such accidents, while prohablv g_r'eater than generally supposed, canno·t br accurately determined because of the work of predators or scaYcngcrs that usu­ ally dispose of \'ictims in a short time. Illegal Hunting Although the closed season in general affords fair protection, illegal hunting takes a moderate hut steady toll of prairie chickens in some parts of the Illinois range. Unfortunatek, m areas where prame chickens ar~ numerous, public sentiment tends to be somewhat indiffer­ ent in regard to protection. Probably the most serious consequences of illegal hunt­ ing come through the loss of occasional birds from sma ll , isolated colonies in the northern part of th e state. Mortality and Populations The foregoing discussion of mortality factors will serve to emphasize the fact that, given proper environment, the prai­ rie chicken has a reproductive rate suffi­ ciently high to cope with predators, dis­ ease, accidents and oth er hazards. As previously pointed out, the welfare of this species in Illinois is dependent chiefly on suitable environment during the nesting period and while the birds are Yery young. It is eviden t that prairie chickens can under certain farming systems maintain themselves for long periods in close con­ tact " ·ith agriculture. Hunting, under the short open season prevailing in Illinois a few years ago, added to other mortalit\' factors, serYed to depress prairie chicke~ populations and undoubt edly constituted a limiting factor in marginal range; nevertheless, it seems apparent that the gun was not the pri­ marr cause of elimination of the prairie chicken from most of its range in dark soil prairie counties of the state. FOOD HABITS Field studies indicate that prairie chick­ ens, particularly the young, feed to some extent throughout the day, hut the main feeding periods are for about 2 hours in the morning, beginning a short time after 402 Iu.1. 01s :'\'AT U RAI. HISTORY SuR\'EY B uuETrx I' ol. 22, A r t . ./- Tuhlc 2.-Foods found in stomachs of 10 adult pra irie chickens collecled in southeastern Illinois in lute June, July and A ugust, 1936 and 1937. Foou \ 'ECETA III.E FooD \\'ild St'l0 ds Huttonwt't'd, l)iodi11 /eres \\'alter .. . . . . ........... . Giant ragweed, ,-/111broii11114id11 Linnaeus . . . . . .......... . Partridgt' pea, Ctuiia Clwmaecriita Linn aeus .............. . Pennsylvania persicaria, Polygonum penniylvanicum Lin naeus \\'ild mustard, BraHica sp.. . . . . . . . . . . .... ............ . )~lack hindweed, I'olygo11u111 Convolvulw Linn aci..s ......... . Yellow foxtail, Setaria glauca (Lin naeus) Beau vais ....... ... . Total wild ieedi . ........ .... .. ................ ......... . Fruit Dewberry, Rubw t'illowi Aiton .......... ..... .......... . Panicle dogwood, Comru pa11irnlata L' Heri ti er d e Hrutelle .. . \\'ild black cherry, I'rrmru urotina E hrhart ............... . Prairie rose, Roia utigera i\ li chaux ....................... . Hawthorn, Crataegw sp . ............ ..... ......... ..... . . Tota/fruit ............................. ... ........ ... .. . Browse Flowering spurge, Euplrorbia corolla/a Linnaeus ............ . Goldenrod, heads and leaves, Solidago sp ...... ............ . Unidentified leaves ..................................... . Total browie . .... ... .. ................................. . Grain \\'heat, Triticum iativ11111 Lamarck . . ..................... . Total grain. . . . . . . . . .... ..... ....................... . ~last Acorns. . ........................................... . Total 111aJ/ . ........................................... . \ 't:getablc debri s ......................................... . ToTAL \'ECETABLE Fooo .....•........................•... ANll',IAL Fooo Insects Short-horned grasshoppers, Acrididae ..................... . Ground hectics, Carabidae. . . . . . . . . . . . . . . . . . . . . . . ...... . Leaf beetles, Chrysomelidae ............................. . Snout hectics, Curculionidae ............................. . Beetles, unidentified ................................... . Cutworms and army worms, Noct uid .. e .................. . I nscct pupae. . . ......... ... ................... . Total inuctJ .. . ToTAL AN1~1A1. Fooo ..................................... . ~ l ~I llER Of STO~IACHS JS WHICH Fooo ITEM Occt' RRED 8 3 2 2 1 ] ] 8 -l 2 1 1 2 3 1 3 6 6 3 1 1 1 2 PER CENT or Fooo ITEMS 8\' \ 'oLUME 21. 2 9 .0 4 .6 0 .8 t race trace t race 24 .5 3 .4 2.0 1.4 t race 9 .3 7. 5 0 .9 4 .7 0 .5 1.2 4 .8 2. 2 0.9 0 .5 0.4 0.1 O. J ToTALS 35. 6 31 .3 17 .7 4 .7 0 .5 1. 2 91 .0 9 .0 9 .0 JI ay, 19-1-3 YEATTER: PRAIRIE CHICKEK 1:-- ILLIXOIS +o3 Table 3.-Foods found in stomachs of H young prairie chickens collected in southeastern Illinois in late June, July and August, 1936 and 1937. FooD VEGETABLE Foon rruit Dewberry, Rubus villosus Aiton . . . . . . . . . ........... . \\'ild black cherry pits, Prunus serotina Ehrhart ...... . Panicle dogwood, Cornus paniculata L'Heritier de Brutelle . Prairi e rose, Rosa setigera l\lichaux ..................... . . Ground cherry seeds and pulp, Plzysalis sp.. . .... ... .. . . Hawthorn, Crataegus sp.. . . . . . . . . . . ............ . Tota/fruit ..... . ... .. .. .. . Grain \\'heat, Triticum sativum Lamarck . Corn, Zea mays Linnaeus .. ...... . Oats, .dvena sativa Linnaeus . Total grain . .............. . . .... . \\'ild Seeds Buttonweed, Diodia teres \\'alter ...... . . . .... . Bull grass, Paspalu.111 sp . .......... ..... . Hairy panic grass, Panimm Juwclmcae Ashe .. Sheep sorrel, Rumex Acetosella Linnaeus . Knotweed, Polygonum aviculare Linnaeus . Yellow foxtail, Setaria glauca (Li nnaeus) Beau vois . Total wild seeds . ... ... . Browse Unidentified leaves . . . . . . .... ..... . . . Goldenrod heads and leaves, Solidago sp. . ............. . Total browse. . . . . . . . . . . . . . . . . . ................. . Vegetable debris .................. . ToTAL \ 'EGETABLE Fooo ....... . A1'IMAL Fooo Insects Short-horned grasshoppers, Acrididae .......... . Long-horned grasshoppers, Tettigoniidae .. Ground beetles, Carabidae ............. ........ . Scarab bee tles, Scarabaeidae . . . ... .. .... . Leaf bee tles, Chrysomelidae ........................... . Stink bugs, Pentatomidae .. ... . Long-horned beetles, Cerambycidae .. Snout bee tles, Curculionidae Lady bee tles, Coccinellidae. Robber fli es, Asilidae ... Ants, Formicidae .. Cutworms and army worms, :"\octuidae . Tiger beetles, Cicindelidae . . Grub parasites, Tiphiidae ..... . Crickets, Gryllidae ............ . Soft-winged flower beetles, l\lelyridae. Leafhoppers, Cicadellidae ... . Total insects . .......... . . Arachnids ............ . TOTAL Ar-:1r.1AL Fooo .. :\'n,IBER OF STO:-.IACHS 1:-l WH I CH Fooo ITEM OccuRRED 7 4 4 1 1 1 6 9 1 2 1 1 5 3 2 12 5 7 2 8 4 1 7 2 3 s 3 2 4 1 1 2 2 P ER CENT OF Fooo I TEJ\I S BY \ 'oLU'ME 13 .2 6.1 2.8 0.4 0 .1 trace 17 .3 1.6 t race 11.8 0 .2 trace trace trace tra<:e 3.5 2 9 0 6 17 .4 4 .2 3.3 3.1 3.0 1.3 1.3 1.7 0.8 0. 7 0 .() 0.4 0.4 0.3 0.1 trace trace 0 .9 T OTALS 22.6 18 .9 uo 6 . ../ 0.6 60. 5 38.6 0.9 39.5 l1.1 l~()IS :'\ATlJR,\I. H ISTORY SVR\' F.Y B Ul.1.ETI:--. I ol. 22, Art . .J sunri,l·. a11d i11 the af tt.'rnoon for an hour or mort' hdort· sundown. I II su111111t·r tht.' adults :11ul young ha\'C frcqut·ntly ht·t·n oh:-er\'ed tlusting along field margin:- t.'a rly on dear mornings pre\'ious to fording. On dark. rainr dars, the fema les and ) oung are likel): to b·e found sitti ng quiet- one-third of the food of chickrns collectrd during the prr iod of ~lay to Octoher, i11clusi\'e . Gross ( Brnt 1932) reported that 17 prairie chickrns , collectrd mostly during the fall in \ Visconsin , had eaten about 72 per cent \'l'grtahle matter and 28 per Fi~. 13.-A cornfield, right, in which numerous prairie chickens fed in the winter of 1938-39, and nearby grassland used as cover. ly along hrdges \\"ell through the usual morning feeding period. 1 n the spring, the males appear to feed little until after the morning booming prriod. Several workers ha\'e investigated the food of the prairie chicken in the Middle \ Vest . Judd ( 1905) analyzed the stom­ achs of 7 I chickens collected in the Mis­ sissippi valley during all months except July. The foml consisted of approximate­ ly -+6 per cent seeds and gra in , 25 per cent browse, including leaves, flowers and hutls, 1-t per cent animal matter, chie fly j.!rasshoppers, 12 per cent fruit and about 3 per cent miscellaneous vegetable matter , mosth· acorns. Ah~mt 31 per cent of the annual diet \\"as !,!;rain, over half of \\"hich \\"as corn. ~early 15 per cent consisted of weed seeds, over half of which belonged to the smartweed family. The fruits eaten were chiefly rose hips. Insects made up ahout cent animal matter. Although more than 160 kinds of animal matter and vegetable matter were found in the diet, it was e\"i­ dent that a dozen items made up nearly 90 per cent of the food. Arranged in the order of percentages of all the food eaten, the 12 leading items were short-horned grasshoppers 26. 7, ragweed 11.0, oats 10.8, clover 7.7, black bindweed 6.2, acorns -LS, greenbrier 3.6, dogwood 3.5. crickets 3.3 , huck\\·heat 3.1, bramble 3.1 and blueberries 2.-t. Schmidt ( 1936) observed during a study of the \\"inter feeding habits of \ Vis­ consin prairie chickens that buds, especial­ ly of birch, hazel and aspen, formed a large part of the diet of males in the northern counties of the state when tem­ peratures were above zero, but that corn o r other grain and weed seeds were taken regularly when the temperatures were be­ low zero. He found that , in the southern \Visco11sin counties, resident birds and ,1/ ay, 19-1-3 YEATTER: PR.\IRIE CHICKEX IX ILLIXOIS migrant females appeared to feed on grain, weed seeds and buds through the winter. Hamerstrom's ( 19+ 1) field studies and experimental feeding of prairie ch ickens in confinement showed that \Visconsin birds eat grains, weed seeds, browse and greens in autumn and "·inter , but throw greater emphasis on the value of cultiYated gra ins, including corn, buckwheat, barley, oats and rve, as winter food. Fieid observations sho"· that waste soy­ beans, waste corn, fig. 13, and weed seeds form an important part of the winter diet of the prairie chicken in southeastern Illi­ nois. As a rule, prairie chickens do not eat shocked corn except during periods of deep snow. Although grain sorghums are not grmn1 extensively in this region, dur­ ing severe weather the birds readily eat sorghum in shocks, if it is available. They eat available weed seeds, as well as grains, throughout the winter and early spring. The crop of a recently killed female found on l\Iarch 29, 1937, was full of soybeans. \Vinter droppings almost in­ variably contain quantities of grass and other green material. Fruits of rose and "·ild grape, as well as other persistent f rnits, are in the diet to some extent dur­ ing the winter. Apparently budding is less common in Illinois than in \ Visconsin. Prairie chick­ ens have been observed eating buds from as early as i'\ov. 9 to early April in south­ eastern Illinois; however, so far as our records go, budding is not a daily practice. Probably green leaves of grass and herha­ ceous plants partially supplant buds in the diet at this latitude, as suggested by Leo­ pold's ( I 93 I ) observations in Iowa. Cot­ tonwood is the chief browse species, hut buds of red maple, elm , apple and proh­ ahl \' several other trees and sh rubs are induded to some extent. Samples of th e summer diet of prairie ch ickens are illustrated in tables 2 and 3, showing percentage by volume of various food items in crops and gizzards of I 0 adult and I+ young birds taken in south­ eastern Illinois during late June, July and August of 1936 and 193 7. As has heen shown by food studies of other gallina­ ceous birds, it is probable that the food ~ =t ,;,~-:-. if :.'-r,; .. ' \ l- , . .,., 'JI/ '/ ~ 'II , ' t::!fJ' .:!ti'< ·~~ ~ fg • I !~';I ,,, ... . ~r ~-·· "~ ) ..... C .,, ( I -;,< ': ,I - , . ·1/.· -..... «-:v••./ "f:!J A B D Fig. 14.-Animal matter found in the crop of a young prame chicken ( approxima1e age 10 weeks). A. Short-horned grasshoppers, M elano plus difierrntialis. JJ •• Short-horned an_cl long­ horn eel grasshoppers, including N roco no cepltalus robustus. C. Leaf-feed_111g heet_les, C:all1graplw similis and Crypto cepltalus venustus. IJ . Jmhri cated ~nout beetles, Epffaerus 1mbnrat11s. -l06 I Lll~OIS :\ ,\TC RAL HI STO RY lJR \"EY 8 ULLET I ~ T' fJ/. 22, Art . ./. of , ery ~ oung prairie chickens consists al­ most entirrlr of animal lllatter, chie fl y in:-ecb. Dur.ing the period of grow th, the diet graduallr changes to seeds, succulent n·getahle lllatcrial. fruits and insec ts char- A sisted chirAr of w aste wheat kernels , many of which had started to sprout. \ Vild fruits , including those of dew­ herry, panide dogwood and wild black cherry, were prominent in the stomach B C D I ' ., ' Fil!. 15.-Anima l m atte r fo un d in the crop of a young prairie chicken ( approximate age 8 weeks). ,-/ . June beetle s, Pl,y/lop/,aga spp. B. Long-horned and short-horned grasshoppers. C. Spider, A r achni da. D . Robber-flies, Asilidae. £. Miscellaneous beetles, bees and wasps. acteristic of t he su mmer diet of the adult . The stomach contents of the H- young birds mentioned above, which aYeraged 9 tu 10 weeks in age, consisted of 60.5 per cent vegetable ma tter and 39.5 per cent animal matter. A nimal matter found in the stomachs of two young prairie chick­ ens is shown in figs. 1 + and 15. The food of the 10 adu lts taken in th e sam e period a~ the young birds consisted of 91.0 per c<:nt vegetable matter and 9.0 per cent animal matter. In the adult stomachs analyzed , wild seeds ( exclusi,·e of fruit) and grains made up o,·er +O per cent of the contents, with weed seeds greatly predomi nating. But­ tonweed seeds constituted over 21 per cent of the total contents. l n the stomachs of the young birds, grain made up a greater Yolume than wild seeds (exclusive of fruit), most of w hich \\·ere buttonweed seeds. T he gra in con- material of both young and adults. Drop­ pings examined in the field in July and early August contained quantities of dew­ berry or other Rubus seeds. Grange ( 19+ 1 ) in \ Visconsin reports that the occurrence of the trailing swamp black­ berry, Rubus hispidus Linnaeus, apparent­ ly determined the distrihution of sharp­ tailed grouse and prairie chickens during a portion of the day and at times for periods of days in the summer of 19+ I. The consumption .hr prairie chickens of large numbers of short-horned grasshop­ pers, figs. 1 + and 15 , must be regarded as a definite asset to agriculture. Other harmful kinds of insects eaten hr the Ill i­ nois prairie chickens include sno~t beetles, scarah beetles, leaf beetles , cutworms and leafhoppers. Certain beneficial forms, in­ cluding ground beetles, lady beetles and grub parasites , were eaten to some extent. There is no evidence from field studies Alay, 19+3 YEATTER: PRAIRIE CHICKEN IN ILLINOIS -l07 that surface water for drinking is essential to either young or adult prairie chickens in Illinois. Probably dew meets part of the water requirements of these birds in summer, as Stoddard ( 1931) found in the case of bobwhites. In addition, the insect diet of the young birds and the fruit and green vegetation eaten by both young and old birds provide moisture when little free water is available. No evidence was found to indicate that prairie chickens made use of a small, intermittent stream in the Jasper County study area. MANAGEMENT Although definite limitations must he recognized in regard to management, it is evident that certain practical measures may be undertaken to insure the survival of prairie chickens in Illinois. That these birds can maintain themselves in good numbers in close contact with certain types of agriculture must be regarded as a highly encouraging sign. However, be­ cause of the possibility of future changes in agricultural practices, the present oc­ currence of prairie chickens over a fairly extensive district in southeastern Illinois must not be regarded with too much com­ placency. Adequate legal protection and a well­ balanced system of public-owned refuges, these refuges involving the use of sub­ marginal prairie lands and serving several kinds of wildlife, are essential to a sound prairie chicken management program for Illinois. Experimental stocking of suit­ able areas with trapped birds offers a possible means of increasing the range of prairie chickens in the state. Certain fa­ vorable land use practices are indispensa­ ble to the increase, or even the survival, of these birds. Needless to say, the suc­ cessful prosecution of a long-time program for the management and conservation of prairie chickens and other wildlife depends to a considerable extent on the degree of public interest and cooperation in such an undertaking. Legal Protection Inasmuch as hunting of prairie chickens in Illinois has been prohibited under the State Game Code since the close of the 1932 season, and the present study was begun only 3 years after closure went into effect, it has been possible to make certain observations relative to the effect of legal protection on prairie chicken pop­ ulations. In the northern part of the state, where prairie chickens have been decreas­ ing steadily for many years, increased pro­ tection has probably been of material as­ sistance in the case of some of the larger remnant colonies. Nevertheless, the amount of prairie chicken range in north­ ern Illinois has continued to decrease since 1933 with the disappearance of numerous small colonies. Obviously, in the northern counties the benefits received under a closed season have not been able to com­ pensate for the unfavorable environment. In the main parts of the southeastern Illinois prairie chicken range, there has been no evidence of a general rise of popu­ lation densities attributable to the closed season. However, prairie chickens have gradually extended their range in this region throughout the period covered by the present <;tudy. Although there is some evidence that this range extension began as early as 1930, when large acreages of farm land were idle , it is notable that it did not cease in the middle l 930's, when much of the idle land was put back into cultivation. It seems probahle that even the relatively moderate hunting pressure exerted during the 1912-1932 period was sufficient to eliminate prairie chickens from the marginal portions of their range in southeastern Illinois , and that reoccupa­ tion of these areas is now possible because of the survival of larger numbers of birds annually. Since prairie chicken population densi­ ties vary widely in different parts of the range , it is almost impossible with the data at hand to arrive at a sa tisfactory estimate of the number of these birds nm~· present in Illinois. It is virtually certain, however, that th e total population is only a small fraction of the number of resident upland game hunters in the state. An a,·­ erage of 12 chickens for each of the ap­ proximately 2,650 square miles comprising the main ranges in northern and south­ eastern Illinois would mean a total of about 32,000 birds. Even if the total num­ ber were twice as large, it would represent less than 1 bird to 5 licensed Illinois hunt­ ers. l\Ioreover, unlicensed hunters, con­ sisting of landowners and tenants and -WS l1.1.1:-:0 1s ;1. ,, TU R,, 1. H1sTORY SuR\' hY B u 1.1.hT1:-: /'ol. 22, ,frt. + their children . all of whom can legally hunt without Iicen:-.es on the farm land on which t hey reside, a re prohahly almost as 1111111erous as licensed hunters. Although the numher of licensed hunters living in till' northern half of the state is prepon­ deran tly grea ter than the number li\'ing in the sou the rn half , many northern hunters go annua lly to southern lllinois for quail hunti ng. In view of the heavy demand for upland game hunting in the localities no\\· inlwhited hy prairie chickens, it is evident that the gun is potentially an important fac tor in the conservation of prairie chick­ ens in Illinois. Legalization of prairie chicken hunting on a statewide basis at the present time would ine\'itably hasten the extermination of the remaining birds in the northern pa rt of the state. Resumption of chicken hunting in southeastern Illinois, except under such rigid restrictions as to furnish little sport for the great majority of hunters, would presumably soon bring a halt to the present extension of range and in time would be expected again to elim­ inate these birds from the poorer portions of their present range. Unless the number of prairie chickens in Illinois can be increased materially, the status of this species of game bird "·ill probably remain doubtful. In spite of the fact that fair-sized prairie chicken pop­ ulations now occur in four or five south­ eastern Illinois counties, and smaller num­ bers in several other counties, until all available range in this region is reoccu­ pied , and until adequate steps are taken to safeguard the colonies in other parts of the state , full legal protection seems adv isable. Loss to farmers through consumption of unh arvested corn by prairie chickens in win te r has sometimes been advanced as a reason for reopening the prairie chicken season. A I though it is true that a num­ ber of compl ai nts of damage were heard from fa rmers in some local~ties following the inc rease of chickens in 1938, onlr minor damage has been reported sinc·e tha t time. There seems little likelihood of increase of p rair ie chicken population densit ies to h igh levels in Illinois except for occasional shor t periods. During pe­ riods of deep snow, which mar temporari­ ly increase consumption of grain by prairie chickens, trapping and transfer of birds to restock unoccupied region:-. offers a means of reducing damage in local areas. Refuges In northern Illinois, adequate ref~ge areas are the first necessitr if the natn•c prairie chickens of that r~gion are to he preserved for the future. In Lee County, northern Illinois prairie chickens are mak­ ing their last stand on approximately 50 square miles of sand prairie along the Green River. .Much of this land consists of low dunes and is submarginal for agri­ culture. Bottomland areas, which are in­ terspersed among the sand lands, are rela­ tively fertile and are farmed or pastured intensively. Some of the pastured areas contain ponds or marshes and are leased for waterfowl shooting. A 1,+00-acre area has recentlr been purchased in Lee County as part· of the Federal Aid in \ Vildlife Restoration Act program to serve as an upland game, fur­ hearer and waterfowl refuge. This area, administered hr the State Department of Conservation, is a forward step toward safeguarding the remnant prairie chicken population, although it is too small for an ideal chicken refuge. An area of 25 square miles probably represents the minimum that would serve as an adequate sanctuary for prairie chickens in this region. The relatively high cost of bottomland soil is recognized as a serious obstacle to the acquisition of an adequate refuge area in the northern Illinois prairie chicken range. Careful blocking to include chiefly light sandy land would reduce the cost of acquisition. Nevertheless, inclusion of marsh areas and ponds would greatly in­ crease the usefulness of such a refuge. These hottomlands furnish important hab­ itats for prairie chickens, fu rhea re rs and other species of wildlife. They are among the few places where waterfowl now nest within the state. A well-managed refuge area of adequate size, consisting of perhaps 80 per cent upland sandy areas and 20 per cent marsh would be an important contribution to the conservation of wild­ life, including a number of species that are now rare as residents or nesting forms within the state, for example, mallards, pintails, blue-winged teals, king rails, up­ land plovers and badgers, in addition to prairie chickens. It should incidentally Jllay, 19./-3 YEATTER: PRAIR I E CH IC KEN I r-.' ILLI N OIS 409 serve al so as a sanctuary fo r prairie fl owers and herbaceous plants, many of which are now rare in the state. This area would, perhaps, eventually develop forest cover if withdrawn entirely from farming and grazing. I ts usefulness as a wildlife sanctuary w ould depend on keeping a large part of it in open grass­ land . To accomplish this might requi re a special program similar to one outlined by Grange ( 19+2) in Wisconsin , includ­ ing perhaps controlled grazing, or farm­ ing on some of the better portions, and also controlled burning practices. Since prairie chickens on the area would undoubtedly feed in winter on nea rby farmed areas, an extensive system of food patches probably would not be stri ctly necessary , but , in case farmin g is adopted in the more fertile areas to mainta in open land, some of the grain crops, especially corn, should be left standing to furni sh winter food for wildlife. From the standpoint of prai r ie chicken management , the chief native vege ta tion required would be species for budding; cottonwood , a favo rite species in south ern Illinois, would seem suitable fo r planting in small numbers in the northern Illinois range. A few aspen, wild cherry, panide dogwood and hazel plantings might also be made if these species are absent. D e­ velopment of widely scattered bramble growth, preferably dewberries, w ould pro­ vide summer food, as well as improve nesting areas. Leasing Land for Refuges Although solid block s or cl ose l y grouped tracts of land are probably th e most satisfactory from the standpoint of administration ·of public-owned refu ge areas, good prairie chicken man agement practices do not require th at refuge a reas he contiguous, provided proper di st r ibution of smaller refu ge areas can be obtained. For example, certain sand prairie town­ ships in northern Illinois which now h ave a few prairie chickens might be conve r ted into good chicken range by leasing, and converting to refuges for a t erm of years, 25 per cent of the total land in t he form of 20-acre , +0-acre o r large r tracts of the poorer farm soil th ro ughout each town­ ship. Except when control of " ·oody vege­ tation is necessary on these areas, no graz- ing should he permitted and adequate protect ion from fire would he necessary. Fanning Practices That prairie chickens are still making a strong stand in the redtop producing area of Illinois demonstrates that these birds are not necessarily eliminated hy agr icul t ure and suggests that the farming practices fo llo\\"Cd in t his area may serve as a guide in ma king management recom­ mend at ions. T he present general characteristics of the southeastern l ll inois prairie chicken range may be summa rized by stat ing that this ra nge consists principally of prairie soils of relatively low fer t ili ty in mixed fa rming a reas w here an nually 6 to 8 per cent of the to tal far m land is id le and about 15 to more than 25 per cent is in redtop. As suggested previously, these areas present favora hle condi tions for prai­ ri e chickens because red top as well as idle field s p roduce cover and nesting places quite ea rl y in the spring, and the redtop is harvested relati vely late, allowing most of th e young birds to get on the wing hefore th e cove r is removed, fig. 16. The densest popul ations of prair ie chickens oc­ cur in localities of rela ti vely high redtop acreages, and , as a ru le, the grea ter the amount of redtop harvested for seed, ra ther th an hay, the hetter the range. Since about half of the acreage of id le land in sou theastern Illinois has developed sufficient g rass to fu rnish nest ing cover, it may be sa id that grass type cover occu­ pies fro m approx imately 20 to more th an 30 per cent of the total fa rm land in the various localities occupied hy prairie ch ick­ ens. Presumably similar acreages of grass­ land and simil ar farming practices wou ld crea te prairie ch icken range anywhere they m ight be applied on the I ll inois prairie. Undoubtedly t he cover requirements may under certain conditions he met hy con­ siderablv smaller acreages of grassland th an th.ose given ahove, as ind icated by Bennitt's ( 1939) studies in Missouri, hut because of the many fac tors involved no conclusions can he drawn here as to mini ­ mum cover requirements. Since the redtop producing area will probably remain the chief potential range of prairie chickens in the state, and mu st he considered as very important in any 4IO l1.1.1.:-.0 1s :-,. ,,TUR,\ L HtsToRY S u R\' EY Bu LL ETJX /'al. 22, Art. -I manaJ.!ement program in\' ol \'i ng these birds, the future of the redtop industry is of special inte res t to w ildlife conser\'a­ tionii;ts. As Burlison, Stewart , Ross & \Vhalin ( 193-l) poin t out , the concentration of redtop sred production in southeastern l llinois, reduction of the avera~e acreage of redtop grown on individual farms will probably result in lo\\'er population densi­ ties than occur at present. Increased graz­ ing will also tend to reduce the amount of habitable range. ~evertheless, the changes forecast hy the study mentioned Fig. 16.-Harvesring redtop. Redtop grown for seed may be cut with a mowing machine a nd stacked ( above ) or with a binder and shocked (below). The latter method of harvest pro­ \' ides better late summer and fall cover for prairie chickens because of the taller stubble. ( Photograph by courtesy of the Department of Agronomy, University of Illinois College of Agricult ure. ) Illinois is due to a combination of factors that favor the continuation there of the present type of farming. However, these au thors \\'arn that , hecause of overproduc­ tion of seed and declining soil fertility under present farming practices, a reduc­ tion of the aYerage acreage of redtop on farms no\\' p roducing this crop is in pros­ pect. In creased g razing of redtop fields hy livestock is ment ioned as a probable part of such readjustment. As far as can now be foreseen, although conditions wi ll continue to favor the sur­ Yi\'a l of prair ie chickens in southeastern aboYe will serve to put the redtop business on a stable, though reduced, basis and they probably will not in themselves eliminate prairie chickens from any large part of the prairie soils these birds now occupy. Even though the general trend of south­ eastern Illinois agricultural practices is slightly unfaYorable to prairie chickens, individual landowners can assist in main­ taining the populations at or near their present levels if they will practice mod­ erate grazing of pastures, avoid burning of idle fields in the spring months and refrain, whenever possible, from disturb- May, 19-1-3 YEATTER: PRAIRIE CHICKEN I:--' lLLJKOIS 411 ing strips of idle grassland in which prai­ rie chickens are known to be nesti ng. In the dark soil counties of Illinois, prior to \Vorld "\Var II, a trend was evi­ dent toward greater use of grass crops for hay, pasture and soil conservation. This trend, now interrupted by the neces­ si ty for greater grain production , may be resumed after the war. Although it is unlikely that future agri­ cultural developments will be of a nature to encourage the return of prairie chickens to large areas of intensively farmed dark soil prairie, it is possible that local con­ ditions will permit the re-establishment of small populations of these birds in cer­ tain places. In some cases, small colonies of prairie chickens have persisted for many years in the dark prairie around grazed marshes, large pastures or other acciden­ tally preserved areas of favorable range. It is our conclusion that only slight changes, consistent with sound farm man­ agement, would be necessary to create fa­ ,,orable environment for prairie chickens on many dark soil prairie farms. Con­ trolled grazing, use of sweet clover as pasture during the spring and early sum­ mer, use of June clover, lespedeza and alsike as hay or seed crops, growing of mixed clover and timothy for hay, and re­ duction of the acreage of land annually plo\\·ed for spring crops, are indicated by field observations to be favorable to prairie chickens in the dark soil counties. Observations made in southeastern Illi­ nois indicate that the practice of supply­ ing strips of undisturbed grassland border­ ing ditch banks and cultivated fields is a possible method of supplementing the present nesting cover in dark soil counties, hut this method must be tried experi­ mentally before conclusions can be reached a-, to its effectiveness. Predator Control The presence of normal predator popu­ lations along with relatively high popula­ tions of prairie chickens on southeastern Illinois farm lands gives a good indication that widespread predator control would be unnecessary or unprofitable in prairie chicken management. On refuges or man­ agement areas, the conditions actually existing on the ground should be the guide to predator control activities. Large numbers of crows on refuges might cause undue loss of nests or young of prairie chickens. Cooper's hawks, if at all numerous, would be undesirable dur­ ing the nesting season. On the other hand, the great majority of species of hawks and owls, as well as predatory mammals, can well be left undisturbed because of their activity in controlling ground squirrels and other rodents. Feral cats and dogs have no place on game preserves. Cats especially may be serious enemies of young prairie chickens ( Lehmann 19+ 1). Normal harvesting of an annual crop of the common furbearing animals might he expected to exercise sufficient control to keep these forms from becoming over­ abundant and unduly destructive. As pre­ viously pointed out, evidence is lacking that foxes in moderate numbers exert any appreciable effect on prairie chicken popu­ lations. However, if it becomes evident that any particular form of predator has increased abnormally and is destructive, special efforts to reduce the population of that form to normal may he necessary. No general program of predator control involving the use of pole traps or other nonselective devices that may take a heavy toll of harmless or beneficial species (Wight 1931) can he recommended for refuge areas. Control should be restricted to individual predators or species for which there is evidence of activities actu­ ally harmful to game hirds. Trapping and Restocking The fact that agricultural practices change periodically on the Illinois prairie in response to market demands, and to de­ velopments in soil, water conservation and other factors, makes it possible that lim­ ited areas from which prairie chickens have disappeared may now or at a later time be successfully restocked hr releasing trapped birds. Other areas of potential restored or increased range include fair­ sized tracts withdrawn from agriculture, such as those surrounding munition plants in prairie districts, and the sites of exist­ ing prairie chicken colonies whe~e land­ o\\·ners are willing to practice special man­ agement measures for the benefit of these birds. Successful transplantation of prame chickens in local areas has been reported ILu :-.:01 s :'\ ., T LR,\L ll 1sToR\' SuR\ ' E\' R u1.1 .1rr1 :-.: Fi~. I i.- T ip- rop traps use