Breeding review of Gray-hooded Gull Chroicocephalus cirrocephalus in Brazil with contributions on nests and egg biometry

Abstract

The Gray-hooded Gull (Chroicocephalus cirrocephalus) is a seabird distributed in almost all South American countries. However, breeding information on the species in Brazil is scarce. In this study, literature review and search in online databases (WikiAves and eBird) were carried out to gather breeding information on the species in the country and nests of the Gray-hooded Gull were recorded on the northern coast of the Rio de Janeiro state. Literature review indicated breeding records in Rio Grande do Sul, Rio de Janeiro and Rio Grande do Norte states. On WikiAves, 19 records of the species with nests, eggs, chicks and breeding colonies were reported between 2009 and 2020, in Macau, Rio Grande do Norte and one adult hatching at Rio Grande do Sul. In August 2019, two nests were recorded at Ubatuba lagoon (22°09′S and 41°18′W) in the Restinga de Jurubatiba National Park, in the Quissamã municipality in Rio de Janeiro. The nests were described and monitored during five weeks. Each nest contained two eggs and was built with the grass Paspalum vaginatum. Over time, the eggs were degraded and disappeared from the nests, without signs of hatching and possible predation. This study compiles for the first time all the breeding information on the species in Brazil and contributes with data about the nests and egg biometry.