Song post selection and territory location by resident sparrows in the central monte desert

The study of habitat selection by birds is crucial to understand their requirements and promote their conservation. In the central Monte desert, Argentina, many patterns of habitat selection by sparrows in relation to vegetation are apparent during spring and summer but dilute during autumn and winter. We hypothesize that activities related to reproduction, which occur only during spring and summer, explain those changes in space use. We evaluate the hypothesis by studying the establishment of territories by three resident species (Ringed Warbling- Finch Poospiza torquata, Many-colored Chaco-Finch Saltatricula multicolor, and Rufous-collared Sparrow Zonotrichia capensis) in an open woodland of Ñacuñán Reserve, Mendoza province. We sampled vegetation and mapped territories during 2005-2008. We evaluated song post selection and used null models to test its association with the location of territories. Consistently, the three species selected algarrobo trees (Prosopis flexuosa) as song posts, established their territories in areas with higher density of algarrobos and with higher algarrobos in the periphery than in the center of the territories. Patterns found at different scales (territory and intra-territory) and behaviors (territorial defense) that had never been explored in the area provided plausible explanations for selection patterns observed in previous studies. The height, density and spatial configuration of algarrobos may be important in the selection of territories. This should be considered to develop management plans for algarrobo woodlands to prevent negative effects in birds due to the increasing loss of these woodlands.