490 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 5 



but midwinter supplies are often less 

 abundant in the woodlands than in farm 

 regions. The difference in average litter 

 size in the two habitats, as shown in table 

 21, is significant. The writers believe 

 that the superior quality and quantity of 

 food characteristic of many farmland hab- 

 itats may be the main reason for the differ- 

 ential in litter size. No comparative data 

 are available for gray squirrels, but it is 

 of interest that 34 litters found in wood- 

 land types averaged 2.68 young, table 20, 

 a number smaller than the average for 

 farmland fox squirrels. 



ILLINOIS HABITATS 



Forest cover is the basic requirement of 

 fox and gray squirrel habitats, and the 

 kinds, combinations and sizes of the trees, 

 shrubs and brambles they contain, and the 



include them under two main headings : 

 black prairie and woodlands. 



Black Prairie Habitats 



The black prairie region of Illinois is 

 overwhelmingly agricultural and is dom- 

 inated by the production of corn, soybeans 

 and wheat. It contains very little wooded 

 area, and therefore has an acute shortage 

 of den trees. Subtypes making up the 

 squirrel range in this region are woodlots, 

 wooded stream bottoms, hedgerows, and 

 fields and farmyards with scattered trees 

 or groves. The woodlots are predomi- 

 nantly oak-hickory. Walnut plantations 

 are widely scattered and aggregate only a 

 very small acreage. In the bottoms, the 

 main trees are elms, maples, sycamore, 

 white ash and other wet-site species ; and 

 on the bluffs, oaks and hickories are the 



Fig. 14. — Typical farm habitat of fox squirrels on Illinois black prairie type, Champaign 

 County, February, 1941. 



density of the stand, to a large extent 

 determine their quality. Since the oc- 

 currence and growth of woody vegetation 

 vary with soil, climate and the activities 

 of man and other animals, the types of 

 squirrel habitats in Illinois are many. 

 Although the variations in squirrel habitats 

 are not readily classified, it is possible to 



principal trees. The only important 

 hedgerow species is the Osage orange, the 

 older and larger hedges of which are now 

 steadily being pulled. Practically all 

 wooded areas on the black prairie are 

 grazed. 



Staple squirrel foods' in this region, in 

 probaljle order of importance, are corn. 



