Winter Feeding of Fox and Gray Squirrel Populations

Abstract

Populations of fox (Sciurus niger) and gray squirrels (S. carolinensis) were provided with shelled corn for 3 winters in a mature mixed hardwood forest and for 2 winters in an even-aged 40to 50year-old oak-hickory forest in Illinois. Mast crops were above average during the study. Corn provided no obvious benefits to squirrels in the mature mixed hardwood forest with respect to reproduction, population density, survival, physical parameters, or reduction in disease. In the even-aged forest, the numbers and recaptures of squirrels were higher where corn was provided. Corn apparently is not a nutritionally adequate supplemental food for squirrels. During 1 winter, squirrels made little use of unharvested corn and soybeans left in fields adjacent to woodlands, but use of corn increased somewhat in March. J. WILDL. MANAGE. 44(1):41-55 Winter is a critical period for fox squirrels (Sciurus niger) (Allen 1943:172), and it is a breeding season for fox and gray squirrels (S. carolinensis) (Brown and Yeager 1945:475). The winter survival of potential breeding squirrels and their reproduction depend mainly on the size of the fall mast crop (Baumgartner 1940; Allen 1943, 1954; Packard 1956; Smith and Barkalow 1967; Nixon and McClain 1969, 1975) and also on the severity of the winter (Goodrum 1938, Terrill 1941, Allen 1943). In winters of low mast and severe weather, squirrel populations may suffer. Fox squirrels readily eat corn during the winter months (Allen 1943:226, Baumgras 1944:296, Brown and Yeager 1945:504, Packard 1956:37, Fouch 1962:217). Gray squirrels may not eat corn as readily as fox squirrels (Packard 1956:41) but it may be part of their diet (Davison 1964). Some biologists believe that under certain conditions, winter feeding may be of value to squirrels (Chapman 1938:683, Allen 1943:299, Brown and Yeager 1945:523, Packard 1956:60, Davison 1964:351, Tittensor 1975:34). Shelled corn has been used in winter feeding of fox squirrels (Baumgartner 1940, Allen 1943) and gray squirrels (Lint 1974), but the results of these supplemental feeding studies have been inconclusive. Our study was designed to determine the effects of supplemental corn supplied in winter to populations of gray and fox squirrels in mature and in pole-sized (average dbh 25.4 cm) mixed hardwood for-