Diverse, Native-Plant Communities as Important Nesting Habitat for Chestnut-Bellied Scaled Quail

Abstract

Habitat loss and fragmentation have been implicated in the decline of chestnut-bellied scaled quail (Callipepla squamata castanogastris) in southern Texas, U.S.A. Although a general affinity of the subspecies for native thornscrub is known, its specific habitat requirements are less studied, and no information exists regarding its demography. We conducted a study in southern Texas (n = 5 ranches; LaSalle and McMullen counties) to 1) quantify survival, reproduction, and occupancy of chestnut-bellied scaled quail and 2) characterize its nesting habitat to help inform future rangeland management. We captured and radio-collared individuals (n = 137) during Mar‒Aug 2013 and 2014 to estimate survival and reproduction and conducted call-count surveys (n = 60 points) during May‒August of both years to estimate occupancy and detection probability. We measured vegetation characteristics at nest sites (n = 53 nests) and paired random points to document habitat use. We documented seasonal survival (0.68‒0.85), clutch size (10‒11 eggs), and apparent nest success (38‒59%) that were within values reported for scaled quail in other portions of its geographic distribution. However, relative abundance was low (0.14‒0.25 calling males/point), as was occupancy (0.56‒0.73) and probability of detection (0.10‒0.32). Regarding nesting habitat, pricklypear (Opuntia engelmannii Salm-Dyck ex Engelm.) was the most common nesting substrate (68%; n = 53 nests), with pricklypear (95% CI β = 0.992‒1.105; P < 0.09), woody plants (95% CI β = 1.001‒1.042; P < 0.04), and native grasses (95% CI β = 0.993‒1.129; P < 0.08) being important variables distinguishing nests from random sites. Nest survival was negatively influenced by non-native grass cover (95% CI β = -0.115 to -0.006). Preservation of diverse shrub and native-grass communities should receive high consideration when planning brush management in southern Texas if conservation of chestnut-bellied scaled quail is a goal.