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 virginia nus ridgwayi), Gambel's quail (Callipepla gambelii), and Arizona scaled qua il (C. squamala pallida) responded in common to the randomly available envi ronment by using patches that apparently reduced risks from raptors and hyp erthermia. Bobwhites used patches with cooler temperatures and lower exposu re to ground and aerial predators than the other species. Gambel's quail us ed patches with higher canopy coverage of woody vegetation and exposure of bare ground in comparison with scaled quail. Multivariate discrimination mo dels (used vs. random patches) indicated a potential for interference compe tition among the quails. However. we interpreted the data to indicate that different manners of habitat use may lead to common outcomes (degree of exp osure 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 additio n of herbaceous cover to Gambel's quail habitat may create masked bobwhite habitat.