Nesting Habitat of Chubut Steamerducks in Patagonia, Argentina

AGUERO, LAURA; GARCÍA BORBOROGLU, PABLO; ESLER, DANIEL

EMU

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2010

0158-4197

We studied nest site selection of the flightless Chubut Steamerduck (Tachyeres leucocephalus) along 292 km of continental and 59 km of island coastline in Patagonia, Argentina, encompassing the species main breeding area, between 2004 and 2006. Almost all nests were located on islands and islets, which ranged in size between 0.5 and 54.4 ha, and were 0.01 to 5.6 km from the nearest mainland coast. Nesting areas were adjacent to the coastline, and located within bays and inlets with shallow waters and protected from waves, winds and strong currents. Logistic regression analyses in an information-theoretic framework were used to compare habitat characteristics between nest sites and random sites; these showed that Chubut Steamerduck nest sites were strongly and positively associated with higher proportions of shrub-type vegetation cover. To a lesser degree, the percentage of silt-clay sediment was positively associated with nest sites. Nest site selection is presumably associated with concealment from aerial predators and protection from weather. This information represents the first study of breeding habitat features and nest site selection of Chubut Steamerducks, and will contribute to management and habitat conservation actions for this rare flightless duck species through identification of both general and specific habitat features that should be preserved or enhanced to provide appropriate nest sites.