WINTER FOODS OF THE BOBWHITE 

 IN SOUTHERN ILLINOIS* 



Edward J. Larimer+ 



This is a report on the winter foods of the bobwhite 

 quail (Colinus virginianus) in southern Illinois. The 

 investigation on which it is based constitutes onephase 

 of the co-operative research program of the Illinois 

 Natural History Survey and Southern Illinois University. 



Data were obtained by inspection of 4,606 crops 

 from bobwhites that were collected during the hunting 

 seasons (November 11-December 11) of 1950 and 1951- 

 Primary consideration was given to determining the 

 kinds of food eaten, to measuring the volume of each 

 food, and to calculating the frequency of occurrence 

 of each (frequency expressed as a percentage of total 

 number of crops collected). An attempt was made to 

 evaluate the effect of weather on the diet and to deter- 

 mine whether any trends in the diet were evident 

 during the short period of time represented. 



ACKNOWLEDGMENTS 



Many people aided in this study; to each I am in- 

 debted. Dr. Willard D. Klimstra, Director of the Co- 

 operative Wildlife Research Laboratory and Professor 

 of Zoology at Southern Illinois University, Carbondale, 

 gave direct supervision and ready assistance. Dr. 

 Thomas G. Scott, Game Specialist and Head, Section 

 of Wildlife Research, Illinois Natural History Survey, 

 aided and encouraged the study in many ways. Mrs. 

 Diana R. Braverman edited the manuscript. The staff 

 of the Illinois Natural History Survey assisted with 

 insect identification. Dr. Alexander C. Martin, U. S. 

 Fish and Wildlife Service, identified several plant and 

 animal food items. John Oberheu, John Stallings, William 

 Biegler, Walter Stieglitz, John Dennis, Mrs. Elizabeth 

 Leighty, and other members of the Cooperative Wildlife 

 Research Laboratory, Southern Illinois University, gave 

 ' valuable technical assistance. The Southern Illinois 

 University Statistical Service simplified the computa- 

 tion and tabulation of the data. Many sportsmen con- 



•Pfoject No. 1 : Cooperative Wildlife Research Laboratory, 

 Southern Illinois University and the Illinois Natural History 

 Survey, co-operating. 



TTechnical Assistant, Illinois Natural History Survey, 

 October 16, 1950-June II, 1951, and October 1, 1952-Decem- 

 ber 31,1953; now Biologist, North Carolina Wildlife Resources 

 Commission. 



tributed bobwhite crops. I am grateful to them as well 

 as to the persons named above. 



Mr. A. E. Staley of Decatur, Illinois, contributed 

 funds to support this investigation, and Mr. Max McGraw 

 of Chicago, Illinois, assisted by arranging a grant from 

 the North American Wildlife Foundation. I gratefully 

 acknowledge the support of these men in making pos- 

 sible the completion of this study. 



DESCRIPTION OF THE STUDY AREA 



The area, fig. 1, within which the investigation was 

 conducted includes the 34 southernmost counties of 

 Illinois. Irregular in shape, the area extends 160 miles 

 north to south and 150 miles east to west and covers 

 approximately 15,000 square miles. Almost a third of 

 the study area lies below the 38th parallel, which is 

 south of Louisville, Kentucky, and all of the area is 

 farther south than northernmost Virginia. 



This area was chosen because it included the major 

 portion of the bobwhite population in Illinois and rep- 

 resented that part of the state which held the greatest 

 potential for bobwhite management. Marquardt & Scott 

 (1952:4-5) reported that 62 per cent of the bobwhites 

 bagged in Illinois in 1950 were from the region covered 

 by the study area; of the 29 counties reporting the "best" 

 kills of bobwhites, 24 were among those included in 

 this study. 



The continental location and latitude of the area 

 result in considerable climatic variation. Mean January 

 temperatures range from 28 degrees F. in the northern 

 part of the study area to about 34 degrees F. in the 

 southern part; during July most of this region has a 

 mean temperature of 78 degrees F. Summer temperatures 

 of 100 degrees F. are not infrequent, and winter tem- 

 peratures as low as -20 degrees F. are occasionally 

 recorded. In the southern part of the study area the 

 growing season is over 200 days long, sufficient to 

 grow crops such as cotton; at the northern border the 

 growing season is about 180 days long. The average an- 

 nual precipitation varies from 38 to over 46 inches, being 

 lower in the north than in the south. March is the wettest 

 month. For most of the area, 50 to 60 per cent of the 

 annual rainfall occurs during the growing season; how- 



