INTERACCIONES INTRAESPECÍFICAS DURANTE LA ALIMENTACIÓN EN GRUPO EN LA GAVIOTA DE OLROG (LARUS ATLANTICUS).

ZUMPANO FRANCISCO; GARCÍA GERMÁN OSCAR

El Hornero

Asociación Ornitológica del Plata

Lugar: Buenos Aires; Año: 2022 vol. 37

0073-3407

In this study, we analyzed the intra-specific interactions that occur between individuals of Olrog?s Gull (Larus atlanticus) while foraging in groups outside the breeding season. Interactions were studied by analyzing behavioral observations of foraging individuals (n=171) at the Mar Chiquita Coastal Lagoon (Buenos Aires Pro-vince, Argentina). We recorded a total of 98 trophic displacements events and 70 kleptoparasitic events, in which successful attacks were 95% and 24% respectively. Juveniles and males initiated de interactions in the 77% of the trophic displacements and 65% of the kleptoparasitic events. The attacks were ?with physical con-tact? in the 55% and 32% of the trophic displacements and kleptoparasitic events, respectively. The main tactic response for both intra-specific interactions was ?avoiding?. The probability of occurring a kleptoparasitism event was related to the prey size. We conclude that juveniles and males were the main initiators of the interac-tions studied and that the main difference between them was the success rate. This study is the first to analyze and discuss the intra-specific interactions that occur between individuals of Olrog?s Gull. Understanding their feeding behavior is important to discover new aspects of natural history and to provide background informa-tion for a threatened endemic species.