9th International Deer Biology Congress

AUTHORS: Andrew R. Little, Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia; Stephen L. Webb, Noble Research Institute, LLC; Brad S. Cohen, David B. Stone, Gino J. D’angelo, Karl V. Miller – Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia

ABSTRACT: In cervids, male mate search strategies are influenced by the spatial distribution and reproductive synchrony of females [1]. Roving is a common strategy employed by males in cases where receptive females are distributed in unpredictable patches across a landscape. However, roving is energetically costly compared to other search strategies, suggesting males should incorporate spatial knowledge during their searching to maximize encounter probabilities with females [2]. For example, males may increase their encounter probability with mates when selecting for patches used by females [3].

To improve our understanding of how males may increase their likelihood of encountering receptive females, we examined changes in resource selection of 21 male and 11 female white- tailed deer (Odocoileus virginianus) during pre-breeding (13 September − 25 October) and breeding seasons (26 October − 27 November) in Harris County, Georgia, USA. Because sexual segregation is common among white-tailed deer populations, we hypothesized that males and females would be sexually segregated during pre-breeding [4]. We also hypothesized that males would align their resource selection with females during breeding season to increase their encounter probabilities.

We observed differential resource selection between sexes and seasons. During pre-breeding, females selected for agriculture and shrub-scrub vegetation types, while avoiding deciduous and evergreen forests, riparian, and developed areas. Interestingly, during pre-breeding, males selected for vegetation types that females avoided (e.g., deciduous and evergreen forests, and riparian areas), suggesting some level of sexual segregation prior to breeding season. During breeding season, females altered their resource selection from pre-breeding by selecting for deciduous forests and water sources (e.g., ponds, impoundments), while avoiding evergreen forests, shrub-scrub, riparian, and developed areas. As expected, males maintained selection of deciduous forests and riparian areas, but avoided vegetation types that females were no longer using such as agriculture and shrub-scrub.
Spatial mapping revealed an overall pattern of shifted resource selection for females between the pre-breeding and breeding periods; this also was evident for males (Figure 1). Spatial depiction of landscape use revealed that the two sexes utilized resources much differently during pre-breeding, a sign of sexual segregation. As expected, the areas predicted to receive the greatest use by females during the breeding season appeared to influence resource selection and the spatial distribution of males. Our research provides insight into how males alter behavior and spatial use of the landscape to match that of females during the breeding season, which should increase encounter probabilities with mates. Future analyses will examine how encounter probabilities may influence male movement behaviors.