Fitness Costs and Benefits Associated with Dispersal in Northern Bobwhites (Colinus virginianus)

Authors

DARRELL E. TOWNSEND II, DAVID M. LESLIE, JR., ROBERT L. LOCHMILLER, STEPHEN J. DEMASO, SCOTT A. COX AND ALAN D. PEOPLES

Abstract

Movements and dispersal distances are fundamental aspects of ecology and evolutionary biology. Northern bobwhites (Colinus virginianus) generally are considered the
least mobile of all gallinaceous species, but dispersal events of bobwhites (commonly referred to as “shuffling”) are well known. Although dispersal may be a key component in regulating population densities and inbreeding avoidance, few studies have attempted to explain relationships between dispersal, mortality and nest success in northern bobwhites. To examine these relationships, we monitored 957 radio-marked bobwhite from 1991 to 1996. Mean dispersal distance did not differ between sexes (P _ 0.699). Mean dispersal distances of adults (2821 m) were shorter than those of juveniles (3411 m; P – 0.042). We found no sex or age-related differences in survival rates among dispersers and non-dispersers. Despite associated risks with increased movement activity in unfamiliar areas, survival rate was 1.5-times greater for dispersers (5 .- 0.72) than non-dispersers (5 =- 0.50). Further, we found no relationships between nest success and dispersal distance. suggesting that dispersal distance had little influence on reproductive output of bobwhites. Thus, dispersers may play a key role in bobwhite population dynamics whereby declining populations escape extinction through recruitment from productive populations.