Habitat selection by breeding WhinchatsSaxicola rubetraat territory and landscape scales

Abstract

We determined breeding season habitat preferences for a declining migrant grassland bird, the WhinchatSaxicola rubetra,using intensive, territory‐scale habitat and invertebrate data, and independently gathered landscape‐scale field survey and remotely sensed habitat data to determine whether the same habitat relationships were evident at both spatial scales. At the territory scale, low‐elevation and a heterogeneous vegetation structure with a high density of perches and tussocks were the dominant features of occupied habitats. The landscape‐scale model successfully predicted areas where breeding Whinchats were more likely to occur, and similar and consistent relationships with habitat features occurred at both spatial scales. However, plant species richness and topographic slope elicited different responses at different spatial scales, with steeper slopes and high plant species richness favoured at the landscape scale, whereas at the territory scale, low plant species richness was preferred and slope did not determine settlement. These differences reflect differences in the way the data were measured and extrapolated. This study identifies important attributes of lowland grassland habitats and landscapes for a stable population of breeding Whinchats, and the analysis shows the good predictive ability of remotely sensed data to model this species' distribution at larger spatial extents. Our findings provide methods for assessing habitat availability for this declining species and for managing habitats and landscapes to provide these essential elements.