Breeding confirmation and habitat utilization of Sooty Shearwater (Ardenna grisea) on Isla de los Estados, Argentina

Abstract

The Sooty Shearwater (Ardenna grisea) is a species facing global decline, nesting on southern hemisphere islands, and migrating to the northern hemisphere during the non-breeding season. Historical groundwork on Wollaston Island in Chile suggested a possible dispersion of breeding grounds along the seaward fringe of the Fuegian islands, including Isla de los Estados. Recent records ranked the species as the second most abundant during the summer near Isla de los Estados, emphasizing the need for continued exploration to locate and understand the potential breeding site on the island. This study confrms the species ́ breeding presence on Isla de los Estados in the Fuegian archipelago, Argentina. Additionally, we present a preliminary evaluation of its habitat utilization. Active burrows were found along the northern coast of the island on slopes with dense, stumpy subantarctic forests and beneath or alongside rocky outcrops overlooking the coast. Future research should aim at estimating the total population for Isla de los Estados, explore habitat use, and gain insights into the year-round distribution of sooty shearwaters at sea for formulating efective conservation strategies.