HIERARCHICAL HABITAT SELECTION AND REPRODUCTIVE SUCCESS OF THE RINGED WARBLING-FINCH IN CHACO WOODLANDS.

Breeding birds must choose habitat at a multiple scales, from landscapes to nest sites. It is important to understand how birds make these decisions and the relationships between these choices and breeding success. Over 3 years, we studied nest-site selection of the Ringed Warbling-Finch (Poospiza torquata) in the semiarid Chaco of Argentina at the scales of the landscape, nest patch, and nest site. At the landscape scale, Ringed Warbling- Finches established nesting territories in shrub-grassland exclusively. Within shrub-grassland, nest patches and nest sites selected differed in few attributes of vegetation cover from patches and sites that were available, and those differences varied from year to year. Only in the year when brood survival and breeding success were lowest did features of sites of successful and depredated nests differ clearly. The Ringed Warbling-Finch selects features of nesting habitat at the landscape, nest-patch, and nest-site scales. Implications of choices at the scales of nest patch and nest site appear to vary by year, but the presence of shrubs, particularly Geoffroea decorticans and Ziziphus mistol, was most frequently important. The species appears to be plastic in its selection of nest patches and nest sites, perhaps because these choices do not lead to consistent selective advantages. [ABSTRACT FROM AUTHOR]