Covey Membership and Size Dynamics in a Low Density Population of Northern Bobwhites

Abstract

Northern Bobwhites (Colinus virginianus) are predicted to maintain optimal covey sizes throughout the non-breeding season to avoid predators, thermoregulate, and forage efficiently. Arguably, population declines that reduce local bobwhite population densities could influence coveying behavior, which may then affect individual survival and population growth rates. We investigated changes in covey size and membership in a declining bobwhite population on private land in southwestern Ohio. Covey densities (range 0.25–1.63 coveys/km2) were lower than estimates from other areas of the bobwhite range. Despite an average 3.2% weekly decline in mean covey size during October–March, two unique coveys merged to form larger coveys on only six occasions and only one radiomarked individual changed covey affiliation (n = 307 radiomarked individuals, n = 57 coveys). Spatio-temporal separation of coveys and low daily movement rates (139.2 m/day) provided little opportunity for contact among adjacent coveys, possibly inhibiting mergers and inter-covey movements of individuals, particularly during winter. We postulate that low incidences of covey mergers and inter-covey movement by individuals were associated with spatial isolation of coveys because of low population densities on our study sites. Such density-dependent social structure would likely lower non-breeding season survival in low-density populations and therefore have implications for population viability.