The Yearling Disadvantage in Alabama Deer: Effect of Birth Date on Development

Male white-tailed deer are subjected to a variety of factors that influence body and antler development when they are yearlings. Nutrition and genetics have received considerable attention as factors that influence this development; however, date of birth has yet to be adequately investigated and theoretically could dramatically influence development in later years. To determine how date of birth influences development of antler and body characteristics at 1.5 years of age, we collected data from yearling male white-tailed deer (Odocoileus virginianus) harvested on 23 Alabama Wildlife management Areas (WMAs) during the 1998-99 and 1999-2000 hunting seasons. We found that early born males had greater body mass, number of antler points, antler beam length, and antler beam circumference than their late born counterparts. Mean birth date of fork-antlered yearlings was earlier (26 Jun) than spike-antlered yearlings (23 July). Yearling males from the Lower Coastal Plain had shorter main beam lengths and less antler points that those from the Appalachian Plateau, Piedmont Plateau, and Upper Coastal plain, but body mass and main beam circumference did not differ. There was also a lower proportion of fork-antlered yearlings harvested on the Lower Coastal Plain than in other physiographic regions. Antler development in the yearling age class has been proposed as a predictor of an animal's potential for antler quality. Because of variability of fawning periods in Alabama and subsequent effects on physical development, as well as differences in physical development among physiographic regions, selective harvest programs based on physical characteristics of yearling males may not be suitable as a means to improve genetic quality of deer populations.

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