Within-yard habitat use by white-tailed deer at varying winter severity

Abstract

Vegetative, topological, and spatial features that were associated with habitat use of radio-collared white-tailed deer ( Odocoileus virginianus, n=17 in 1996–1997 and n=13 in 1997–1998) were identified as snow depth changed in the Odell Deeryard, NB, Canada. Logistic regressions and classification trees revealed that use of forest stands varied with snow depth, and between the 1996–1997 and 1997–1998 yarding periods. Stand use at all snow depths was inversely related to the distance to stands with >50% softwood canopy cover (SCC). Stand use during periods of low snow depth (<20 cm) also was predicted by features such as the basal area of spruce ( Picea spp. A. Dietr.) <2.5 m 2/ha and browse availability >10% of ground cover. At moderate snow depths (20–50 cm) deer were more likely to use stands within 290 m of 30–50% SCC, within 215 m of >50% SCC, and having low slopes (<4.5°). During periods of deep snow (>50 cm) only those features that described shelter were useful in predicting habitat use variation between years. Deer were not associated with browse-related features when snow depth exceeded 50 cm. In 1996–1997, a winter of average snow depth, deer were more likely to use stands with low perimeter:area ratios (<0.04 m/m 2), within 220 m of cedar/hemlock-dominated ( Thuja occidentalis L./ Tsuga canadensis (L.) Carr.) stands, and with low basal areas of pine/larch (<0.3 m 2/ha, Pinus spp. L./ Larix laricina (Du Roi) K. Koch). In 1997–1998, an exceptionally harsh winter, deer left the yard in late January and moved to nearby timber harvest operations. However, while in the yard, deer selected stands at lower elevations (<180 m), but did not differentiate between softwood shelter species. Results suggest that deer use stands based on the spatial arrangement of shelter within the deeryard, and not just that of the individual stand. We suggest that the supply of browse during winter should be an explicit part of any deeryard management plan.