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

MUSMECI, LUCIANA RAQUEL; BALA, LUIS OSCAR; ELIAS, RODOLFO; CASTILLO, JOANNA MIRIAM; HERNÁNDEZ, MARÍA DE LOS ÁNGELES

San Juan

Conferencia; VII North American Ornithological Conference; 2020

Knowledge dietary requirements in stopover sites is a key to conservation of shorebirds and the habitats that they use. Intertidal flats of south of South America are important stopover sites for many species of shorebirds. The diet of Hudsonian Godwit (HUGO) and White Rumped Sandpiper (WRS) was evaluated during different stopover dates throughout 2018 and 2019 at Caleta Malaspina, Argentina through the faecal analysis. Frequency of occurrence of prey was calculated and compared. Also, the trophic niche breath and the size-class of the main preys was estimated. In addition, was studied the trophic supply through benthic samples, and was estimated the abundance and diversity of invertebrate community of each date. The shorebirds consumed items representing at least 12 taxa, but only a few taxa comprised the main resources consumed. The intraspecific dietary composition of shorebirds was similar, but interspecific composition was different in all dates. 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. Also, the HUGO captured larger polychaetes than the WRS. The density and diversity of invertebrate community was similar among dates. These results show innovative data about the trophic resource use by shorebirds in the study area, and indicate a differential use of food resources in the taxonomic composition and in the sizeclass of the main items captured by shorebirds during their migratory stopover.