Fall and Winter Habitat Use by Scaled Quail in Southeastern Arizona

Abstract

Scaled quail (Callipepla squamata pallida Vigors) are closely associated with semidesert grasslands of the southwestern United States, and populations have declined by as much as 50% since 1960. Livestock grazing, shrub encroachment, and exotic grass invasion are considered important factors reducing scaled quail distribution and density in Arizona. We investigated habitat use by scaled quail across their range in southeastern Arizona to determine the habitat conditions important for survival and reproduction. Pointing dogs located quail during autumn and winter of 2002-2003 and 2003-2004, and we measured habitat characteristics at 52 flush sites and 54 nonuse plots, where scaled quail were not found. We recorded information on landform, substrate, vegetation, and cover. Scaled quail used areas with grass canopy cover 26%, tree canopy cover 10%, and higher grass species richness than randomly available. Short (50 cm tall) visual obstruction (i.e., cover), usually associated with low shrubs, cacti, and bunchgrass, was greater at use sites than at nonuse plots. A logistic-regression equation, including visual obstruction and tree canopy variables, correctly predicted 91% of quail use sites. Greater amounts of visual obstruction and lower percentages of tree canopy cover best-predicted scaled quail sites. Land management practices that reduce grass species richness and cover and increase tree cover may reduce scaled quail habitat quality and availability in southeastern Arizona. Based on habitat use patterns of scaled quail, we recommend that semidesert grassland habitats contain a maximum tree canopy of < 6% and . 25% grass canopy cover at the 20-cm height to provide optimum cover availability.