Comparative Habitat Use by Three Quails in Desert Grassland

During 1994-1996, we studied comparative habitat use by 3 sympatric quails in southern Arizona, USA, to better understand habitat partitioning and the potential for interference competition. Masked bobwhites (Colinus virginianus ridgwayi), Gambel's quail (Callipepla gambelii), and Arizona scaled quail (C. squamata pallida) responded in common to the randomly available environment by using patches that apparently reduced risks from raptors and hyperthermia. Bobwhites used patches with cooler temperatures and lower exposure to ground and aerial predators than the other species. Gambel's quail used patches with higher canopy coverage of woody vegetation and exposure of bare ground in comparison with scaled quail. Multivariate discrimination models (used vs. random patches) indicated a potential for interference competition among the quails. However, we interpreted the data to indicate that different manners of habitat use may lead to common outcomes (degree of exposure to predators) in risk avoidance; thus, the potential for interference competition probably was low. We surmised that the addition of woody cover to scaled quail habitat may create Gambel's quail habitat, and the addition of herbaceous cover to Gambel's quail habitat may create masked bobwhite habitat.