Scaled qual use of different seral stages in the Chihuahuan desert

The Chihuahuan Desert of the southwestern United States and northern Mexico is the primary habitat of the scaled quail (Callipepla squamata), but populations have declined over much of this area since 1960. Because changes in ecological condition of Chihuahuan Desert rangelands may explain the decline in scaled quail populations over the last 37 years, we conducted scaled quail counts seasonally (1988-89) on sites in late- and mid-seral ecological condition in southcentral New Mexico. On the basis of percent cover, grasses were the most important plant group on the late-seral site (65-70% remaining climax vegetation), while shrubs dominated the mid-seral site. The main effect of ecological condition (35-40% remaining climax vegetation; P = 0.48) and the interaction of ecological condition with season (P = 0.69) were not significant for scaled quail observations, but the main effect of season was significant (P < 0.05). Scaled quail observations in grassland, shrub-grass, and grassland communities differed from expected values. When data were pooled across seasons, more scaled quail were observed in shrub-grass mosaic communities than shrubland and grassland communities (P = 0.07). Fewer sightings of scaled quail were made in grassland communities near climax than in shrubland communities in an early seral stage. Availability of food sources and protective cover were apparently primary determinants of habitat use by scaled quail. Data from our study indicate that areas with a mixture of late-and mid-seral plant communities will provide the best available habitat for scaled quail in the Chihuahuan Desert