Consistent nest-site selection across habitats increases fitness in Asian Houbara

Abstract

ABSTRACT Nest-site choice profoundly influences reproductive success and the survival of incubating adult birds. Asian Houbara (Chlamydotis macqueenii) nest in subtly contrasting habitats where the main cause of nest failure is predation. We examined nest-site selection across 3 semiarid shrub habitats that differed in vegetation structure and hypothesized that increased concealment would reduce nest predation. We quantified vegetation structure at 210 nests and 194 random control sites at 2 scales, the “nest area” (50 m radius, considering mean “shrub height” and mean “shrub frequency”) and “nest scrape” (2 m radius, considering a “concealment index”). Variance ratio tests showed that variance in both shrub height and concealment index was lower at nests than at random sites, indicating nonrandom selection. Analysis of the probability of nest occurrence for nest area indicated consistent selection of intermediate shrub heights (shrub height + shrub height2) in the Astragalus, Salsola arbuscula, and S. ri...