Post-hatching brood amalgamation in Northern Bobwhites

Our understanding of the frequency of brood amalgamation in the Northern Bobwhite (Colinus virginianus) is largely anecdotal. Information on it is important in understanding survival and reproduction. We captured entire bobwhite broods at 3-4 and 10-12 d of age and individually marked each bobwhite chick within a brood. Broods were considered amalgamated if novel unmarked or marked individuals or significant differences in body mass or flight ability among chicks were observed. During 2002, minimum frequencies of brood amalgamation within bobwhite broods were 6.7% at 3-4 d and 20.7% for 10-12 d-old broods. During 2003, minimum frequencies of brood amalgamation ranged from 0.0% at 3-4 to 22.2% for 10-12 d-old broods. Our results indicate bobwhites exhibit higher rates and earlier onset of brood amalgamation than previously documented among the Galliformes. Causes of brood amalgamation in bobwhite may differ from those proposed for waterfowl due to the bobwhite's limited mobility, short lifespan, gregarious behavior, and resulting potential for relatedness among individuals. Molecular techniques should be used to assess the effects of inclusive fitness losses and gains among bobwhites that donate and receive chicks. Bobwhite researchers should recognize the potential bias in chick survival estimates caused by high rates of brood amalgamation.