Status of breeding birds at Observatorio and Goffré Islands, Argentina

Continental islands are often sites of low diversity and endemism, as well as important areas for the protection of bird populations, especially seabirds. On Isla Observatorio and the Año Nuevo Islands, in the Southwestern Atlantic, the latest assessment of avifauna dates from more than 20 years ago. In this study, we use a combination of methods to update the status of the main seabird colonies and the most abundant avian terrestrial predator at Observatorio and Goffré Islands during the breeding season. In only 4.5 km2, the islands would harbour ~ 90,000 breeding seabirds. Seabird colonies occupied different areas of the islands and varied in their population status, with Imperial Shags (Leucocarbo atriceps) showing an increase and Southern Giant Petrels (Macronectes giganteus) a decrease according to the last surveys. Magellanic Penguin (Spheniscus magellanicus) population estimations also suggest a decrease but the last survey was based on total, and not on occupied nest sites. We recorded and assessed one new breeding species: The globally near-threatened Striated Caracara (Phalcoboenus australis), which has an important breeding population of around 15 territorial pairs at Observatorio Island. These islands appear to be an important regional bird site and future studies would determine their trends and threats, especially those related with invasive species.

Fil: Balza, Ulises. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina

Fil: Liljesthrom, Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina

Fil: Pimper, Lida Elena. Administración de Parques Nacionales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Franco Navarro, Ignacio. Instituto Español de Oceanografía; España

Fil: Cañas Barrovecchio, Silvia. España Pingüinos; España

Fil: Zunino, Francisco. Administración de Parques Nacionales; Argentina

Fil: Domato, Ignacio. Administración de Parques Nacionales; Argentina

Fil: Acardi, Soraya Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Facultad de Medicina ; Instituto Universitario de Ciencias de la Salud - Fundacion H. A Barcelo;

Fil: Iturraspe, Rodrigo. Universidad Nacional de Tierra del Fuego; Argentina

Fil: Cano, Joaquín. Universidad Nacional de Tierra del Fuego; Argentina

Fil: Raya Rey, Andrea Nélida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego; Argentina