September, 1945 



Brown & Yeager: Squirrels in Illinois 



531 



and 2.43 in summer. The eyes of juve- 

 nile squirrels open at about 4 weeks; 

 weaning occurs at about 8 to 10 weeks, at 

 which time the hair is well developed. 

 Young squirrels become fully self-sustain- 

 ing when between 3 and 4 months old. 



24. Illinois squirrel habitats are of 

 two types, agricultural and woodland. 

 The former consist mainly of farm wood- 

 lots, hedgerows and wooded stream 

 valleys ; the latter, the more extensive 

 wooded areas, both upland and bottom- 

 land in character. The upland and 

 bottomland types combined provide rough- 

 ly 6,750,000 acres of squirrel range in the 

 state ; agricultural types provide a much 

 smaller acreage of habitable range. 

 Minor habitat types consist of reforested 

 stripmines, estates, parks, college campuses, 

 and many towns and cities. 



25. During this investigation, a total 

 of 76 kinds of food plants for Illinois 

 squirrels were recorded; these included 56 

 trees and shrubs, 2 vines, 4 brambles, 6 

 wild herbs, 7 cultivated crops and various 

 fungi. Six groups provided most of the 

 staple foods — -hickories (including pecan), 

 oaks, walnuts, elms, mulberry and field 

 corn. In Illinois almost any fruit may be 

 important seasonally or locally. Mixed 

 stands produce the greatest variety and 

 abundance of food. Cultivated crops, 

 mainly corn, are of far greater importance 

 to fox squirrels than to gray squirrels. 

 No study of the animal food of squirrels 

 was made. Squirrel food shortage ap- 

 peared to be rare on Illinois range. 



26. Illinois squirrels follow a some- 

 what distinct order of succession in the 

 utilization of foods. In late winter or 

 spring they feed on the buds and then the 

 flowers and seeds of elms, maples and other 

 hardwoods. Later they make use of mul- 

 berries and bramble fruits. The mast 

 season, from July or August through Oc- 

 tober, is the period of greatest food abun- 

 dance. 



27. Squirrels show definite preferences 

 when several foods are abundant at one 

 time. Hickory nuts seem to rank first 

 with both fox and gray squirrels. 



28. Storing or caching, which seems 

 to be instinctive in squirrels, is apparently 

 an extension of the morning and afternoon 

 feeding periods during the mast season. 

 The stored foods observed in the present 

 study were mainly nuts and acorns. 



29. The gnawing of bones, observed 

 in both squirrel species, may be for the 

 purpose of obtaining minerals. 



30. Fox squirrels apparently are able 

 to inhabit range lacking open water, pro- 

 vided succulent foods such as green corn, 

 blackberries or Osage orange fruits are 

 available. Gray squirrels were never 

 found on areas entirely devoid of open 

 water. 



31. Both fox and gray squirrels use 

 cavity and leaf nests, and in both species 

 cavities are important as young-rearing 

 sites. Either type of nest appears to meet 

 the essential requirements of either species, 

 but both types of nests are found in the 

 habitats of highest quality. Squirrels 

 utilize practically any kind of tree 

 for nest location, but, because of abun- 

 dance and statewide distribution, the oaks 

 are by far the most important group. 

 The oaks, maples, American elm, white 

 ash, beech, sweet gum, and, in extreme 

 southern counties, cypress and tupelo gum 

 are the chief sources of nest cavities for 

 Illinois squirrels. 



32. Squirrel hunters are mainly farm- 

 ers, laborers and small-town businessmen. 

 Slightly more than one squirrel killed per 

 hour was reported by a group of 236 Illi- 

 nois hunters in 1940 and 1941. A bag 

 figure believed to be more nearly represen- 

 tative for Illinois is between 0.5 and 1.0 

 squirrel per hour. Crippling loss, calcu- 

 lated from hunters' reports, was about 15 

 per cent of all squirrels known to have 

 been hit; this figure does not take into 

 account the loss in squirrels not known to 

 have been hit. The 12-gauge shotgun 

 was the most popular arm of Illinois 

 hunters, followed by the .22-caliber riHc 

 and the 16-gauge shotgun. 



33. The calculated squirrel kill in 

 Illinois in 1942 was 1,463,305 animals, of 

 which 64.7 per cent were fox squirrels and 

 35.3 per cent were gray squirrels. The 

 northern zone produced 11.4 per cent, the 

 central zone 29.1 per cent and the southern 

 zone 50.5 per cent of this kill. A total 

 of about 1,240,000 pounds of high quality 

 meat was produced, practically all of 

 which was used for human food. 



34. In general, good forest practices, 

 especially the maintenance of mixed, all- 

 age stands and protection from fire and 

 grazing, lend themselves to good squirrel 

 management. Selective cutting, except 



