Differential Use of the Trophic Resource by Neartic Shorebirds in a Coastal Wetland in the Argentine Patagonia

MUSMECI LUCIANA RAQUEL; HERNÁNDEZ MARIA DE LOS ÁNGELES; ELÍAS RODOLFO; CASTILLO JOANNA MIRIAM; BALA LUIS OSCAR

Congreso; VII North American Ornithological Conference; 2020

American Ornithologial Society

Knowledge about dietary requirements in stopover sites is a key to conserve shorebirds and their habitats. In the south of South America, intertidal flats are important stopover sites for many shorebirds species. Hudsonian Godwit (HUGO) and White Rumped Sandpiper (WRS) diet was evaluated from faecal analysis. Faeces were collected in different sample days throughout 2018 and 2019 at Caleta Malaspina, Argentina. Prey occurrence frequency was calculated and compared. For the main preys ingested by shorebirds, the size-class structure was estimated. In addition, the trophic supply was studied through benthic samples and the abundance of invertebrate community was estimated. Shorebirds consumed prey items represented by one 12 taxa least, but only a few taxa comprised the main resources consumed. The intraspecific shorebirds dietary composition was similar, but interspecific composition was always different. The main prey consumed by HUGO were polychaetes of Nerididae, Orbiniidae and Onuphidae families, while the WRS captured mostly polychaetes of Spionidae family, small crustaceans and clams. HUGO captured larger polychaetes than WRS. The invertebrate community density was similar in samples taken in different days. These results show innovative data about the trophic resource use by shorebirds in the study area, and indicate a differential food resources use in two ways, in the taxonomic composition and in the main items size-class structure captured.