Breeding Season Survival and Habitat Use of Scaled Quail in Southeastern New Mexico

Abstract

In recent decades, woody plant cover has increased across many North American grasslands, with important implications for wildlife habitat availability. Scaled quail (Callipepla squamata), a declining ground-dwelling bird species, is known to use woody vegetation in arid and semiarid rangelands. However, it is unclear how vegetation changes due to woody encroachment affect scaled quail space use or if scaled quail perceive various species of woody cover differently. We examined breeding season habitat use and survival of scaled quail in 2018 and 2019 in southeastern New Mexico, USA, in a landscape with various species of shrubs, including mesquite (Prosopis L. spp.), which is thought to have increased over time. We used generalized linear mixed models (GLMMs) to compare vegetation characteristics between used quail locations and random (available) locations. We used resource selection functions (RSF) to examine selection for dominant vegetation cover types and anthropogenic features at the third order (within home ranges). We also investigated the influence of third-order selection and weather on quail survival (adult and brood). We found that both brooding and nonbrooding quail preferentially used locations with greater visual obstruction and high densities of tall (≥1.5 m) shrubs relative to availability. Within home ranges, scaled quail selected for proximity to mixed shrub cover, mesquite cover, and bare ground but demonstrated weak avoidance of herbaceous-dominated patches. However, third-order space use did not affect daily survival probability for either adult quail or broods. The only variable related to quail survival was daily average wind speed, which was positively associated with brood survival. Our findings highlight the importance of shrubs as a source of visual, thermal, and olfactory cover for scaled quail. In increasingly shrub-dominated communities, we recommend that scaled quail management plans prioritize practices that create spatially and compositionally diverse vegetation, including patches of tall, dense shrubs.