Comparative habitat ecology of Texas and masked bobwhites

The habitat ecology of masked bobwhites (Colinus virginianus ridgwayi) is p oorly understood, which hampers recovery efforts for this endangered bird. During 1994-96, we analyzed the habitat ecology of masked bobwhites in sono ra. Mexico, and Arizona and compared these findings with the habitat ecolog y of Texas bobwhites (C. v. texanus) in southern Texas. Mean values for the quantity of low screening cover (<50 cm aboveground), operative temperatur e (degrees C), and exposure to aerial predators were relatively constant ac ross regions (CV <14.2%), indicating these variables are important in adapt ive habitat-use decisions by bobwhites. Bobwhites exhibited preference in a ll regions for higher canopy coverage of woody vegetation, lower exposure t o aerial predators, and lower operative temperatures in comparison with ran domly available conditions. The major habitat deficiencies for masked bobwh ites were lack of woody and herbaceous cover, which led to high exposure to aerial predators in Sonora and Arizona. High operative temperatures at qua il level were associated with the loss of greater than or equal to 24% of p otential habitat space-time in Texas, Sonora, and Arizona. Management to im prove habitat for masked bobwhites includes any practice that increases can opy coverage of woody vegetation, and height and coverage of herbaceous veg etation.