Not Only Habitat But Also Sex: Factors Affecting Spatial Distribution of Little BustardTetrax tetraxFamilies

Abstract

Species distribution patterns are determined not only by habitat preferences but also by biotic factors. Particularly, the presence of conspecifics may yield different types of benefits and costs for the individuals involved. This study analyses the spatial distribution of Little Bustard families during the breeding season in relation to the dis- tribution of male core areas in three Spanish populations of the species. A compositional analysis is used to evaluate habitat selection and the habitat types most preferred by females with offspring. Spatial analyses were performed to evaluate the proximity of Little Bustard families to male core areas and male displaying sites. The habitat selection pat- tern was similar between regions, with semi-permanent vegetation and stubbles as most preferred habitats while oth- ers, such as ploughed land, were avoided. Families were located closer to male core areas than expected by chance and were spatially associated to male displaying sites. Little Bustard females may obtain different benefits from this spatial association such as access to more food resources and chances for second matings after a clutch loss. Also in stubbles, the capture of prey by chicks would be easier and semi-permanent habitats would serve as shelter. These results high- light the importance of intraspecific interactions in the definition of the habitat selection pattern of females and fami- lies. This study shows how spatial point pattern analysis may be a useful tool for integrating landscape and behaviour- al ecology.