Resumen

BERON, María Paula. Diet of juveniles of Olrog's Gull (Larus atlanticus) in estuaries of Buenos Aires Province. Hornero [online]. 2003, vol.18, n.2, pp. 113-117. ISSN 1850-4884.

In this paper I present information on the diet of juveniles of Olrog's Gull (Larus atlanticus) in two estuaries of Buenos Aires Province (Mar Chiquita and Punta Rasa). The grapsid crab Chasmagnathus granulatus was the most important prey (in frequency as well as in abundance) in both sampling sites. Other crab species were occasionally present in the diet. The average size of consumed Chasmagnathus granulatus differed significantly between the two sampling sites. The number of crabs per pellet was lower than that observed in previous studies, and crab sizes were smaller than those consumed by adult gulls. This preference for smaller crabs could be related with lower costs of capture and handling in these preys.

Palabras llave : Chasmagnathus granulatus; diet; grapsid crabs; Larus atlanticus; Olrog's Gull.