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Deer Foods during Years of Oak Mast Abundance and Scarcity

1975; Wiley; Volume: 39; Issue: 2 Linguagem: Inglês

10.2307/3799910

1937-2817

Richard F. Harlow, James B. Whelan, Hewlette S. Crawford, John Skeen,

Ecology and biodiversity studies

Rumen contents of white-tailed deer (Odocoileus virginianus) during November and early December of 1966 through 1973 in a mountainous area of southwestern Virginia revealed that acorns made up an average of 76 percent by volume of the deer's diet when acorns were abundant. When a mast failure occurred, deer replaced acorns with large amounts of the leaves of prostrate evergreen plants and shrubs and mushrooms. Proximate analysis of rumen contents revealed that diets containing acorns were higher in nitrogen-free extract and crude fat and lower in mineral content. In mast-free diets both mineral matter and protein increased. Proximate analysis and in vitro tests of composite diets indicated that when mast was present the diets were more digestible and were higher in fat and soluble carbohydrates. A relatively low value of 1.5 kcal/g for estimated digestible energy in mast-free diets suggests that when deer must rely on this type of diet during the winter season, their energy requirement for maintenance may not be met. The addition of oak mast to winter diets increased estimated digestible energy to 3.1 kcal/g, or a level adequate to meet the maintenance energy requirement. A forage inventory in the major forest types indicated that mature stands of pitch pine-bear oak (Pinus rigida-Quercus ilicifolia) produced the greatest quantity of important staple foods for deer during late fall and early winter. J. WILDL. MANAGE. 39(2):330-336 Oak mast predominates in the fall and winter diets of white-tailed deer wherever and whenever it is abundant in the Southeast (Ruff 1938, Pearson 1943, Pearson and Burnett 1940, Harlow 1961, Harlow and Hooper 1971). Acorns are often available to deer for eight months or more (Goodrum 1959). They are high in carbohydrates (King and McClure 1944, Morrison 1957) and provide energy and nutrients during the winter. During years of oak mast scarcity deer must turn to other forages. In this study, data from 1966 through 1973 are used to compare the effects of oak mast abundance and scarcity in late November on food selectivity patterns of deer. Nutritional values of rumen samples and of composite diets reconstructed from rumen analysis were estimated. Important forages available to deer were inventoried in the major forest types of the study area. DESCRIPTION OF THE STUDY AREA The Broad Run Wildlife Research Area in Craig County, Virginia, is within the Ridge and Valley Province. The soils are derived from shale, sandstone, and conglomerate bedrock. Thirty-five percent of the approximately 3,035-ha area is composed of the pitch pine-bear oak forest cover type; 33 percent, oak-hickory-yellowpoplar-white pine (Quercus spp.-Carya spp.-Liriodendron tulipifera-P. strobus) type; and 19 percent, mixed oak-pine type (Whelan 1962). Site indexes (the height which upland oaks attain in 50 years [Olson 1959]) range from 35 to 60 with pitch pine-bear oak containing the lowest index. Elevations range from 469 to 689 m above sea level. Slopes range from 0 to 58 percent and face primarily northwest. From 1959 to 1964, approximately 389 ha (12 percent of the study area) were dis330 J. Wildl. Manage. 39(2):1975 This content downloaded from 207.46.13.149 on Mon, 03 Oct 2016 04:08:45 UTC All use subject to http://about.jstor.org/terms DEER FOODS AND OAK MAST AVAILABILITY * Harlow et al. 331 turbed by clearcutting and heavy selection cutting. In 1957, 23 wildlife clearings were established which ranged in size from 0.30 to 1.33 ha. Seneca (1961) estimated 120 deer on the study area, or 1 per 27 ha. Hunter observation and annual kill statistics indicate little change in deer numbers since 1961 (Weekes 1974).