510 



Illinois Natural History Survey Bulletin Vol.23, Art. 5 



stomachs could often be identified by odor 

 or appearance. 



Minerals 



The mineral requirements of squirrels 

 are not well known. Little information 

 on the subject was gathered in this investi- 

 gation. As reported previously (Carlson 

 1940, Coventry 1940), bones are eaten by 



squirrels were never found at any appreci- 

 able distance from open water. 



Some evidence is available that mul- 

 berries, plums and other succulent fruits 

 serve as water sources for Illinois fox 

 squirrels. Robert E. Hesselschwerdt of 

 the Illinois Natural History Survey did 

 not find that fox squirrels on the Urbana 

 Township Wildlife Area showed a ten- 

 dency to migrate during the extremely dry 



Fig. 31. — Examples of squirrel "cutting" on nuts of the small pignut, Carya ovalis. The 

 thin hull and shell of this species, in addition to the sweet-flavored meat, make it highly at- 

 tractive to both fox and gray squirrels. 



both species of squirrels, perhaps for the 

 purpose of obtaining minerals. Baum- 

 gartner (1939fl) reported that fox squir- 

 rels eat soil to obtain mineral salts. Soil 

 was found in small quantities in some of 

 the stomachs opened by the present writers. 



Water 



Water apparently is not a requirement 

 of the fox squirrel habitat, but it seems 

 to be a necessity in the habitat of gray 

 squirrels. The tracks of both species are 

 often found in the mud or sand at the edge 

 of streams, ponds and lakes. It was not 

 determined in the present study how often 

 squirrels drink, but observations on ani- 

 mals and study of tracks indicated that 

 during the warmer months gray squirrels, 

 at least, take water daily. A comparison 

 of typical habitats of the two Illinois spe- 

 cies leads to the conclusion that the gray 

 squirrel is more exacting in its water re- 

 quirements than its larger cousin. Gray 



summer and early fall of 1940, when all 

 open water within 2 or 3 miles had dis- 

 appeared. During this period the squir- 

 rels made free use of Osage orange fruits 

 and of green corn and apples, from which 

 sufficient moisture may have been obtained. 

 On the Mason County area, wild grapes, 

 blackberries and wild plums probably 

 supplied needed moisture during periods of 

 drought. Other observers, including 

 Allen (1943), have noted the ability of 

 fox squirrels to survive on uplands far 

 from open water. Terrill (1941), work- 

 ing in Missouri, found that extreme 

 drought, resulting in the withering of 

 succulent foods, tended to concentrate both 

 fox and gray squirrels around ponds or 

 other open water sources. _ 



NESTING 



As has been reported by many writers, 

 fox and gray squirrels throughout their 

 range utilize both leaf and cavity nests. 



I 



