Colaboración científica con la Armada de Chile en estudios ornitológicos a largo plazo en el archipiélago Diego Ramírez: Primer monitoreo del ciclo anual del ensamble de aves en la isla Gonzalo

Biocultural conservation increasingly requires transdisciplinary collaborations, which includes different disciplines, institutions and actors. The collaboration between scientists and the Chilean Navy has been an effective way to address this requirement. This inter-institutional collaboration between the Navy and the Sub-Antarctic Biocultural Conservation Program (University of Magallanes, Institute of Ecology and Biodiversity and Omora Foundation in Chile, and the University of North Texas in the US) enabled us to initiate in 2016 long-term ornithological studies in the Diego Ramirez archipelago, which includes the southernmost islands of the American continent. Until now, its avifauna has been studied exclusively during summer seasons, despite the fact that birds are one of the most sensitive and fastest responding groups of animals to climate change; modifying their periods of migration, residence and nesting, their population sizes, and their latitudinal distribution areas. In addition, subpolar regions are especially sensitive to climate change and studies in the Cape Horn Biosphere Reserve, adjacent to the Diego Ramirez archipelago, suggest that some species could be expanding their latitudinal distribution spheres and changing their migration dates. The objective of this work is to initiate a systematic monitoring of the species composition and the nesting, migration and/or residence dates of the Diego Ramirez archipelago birdlife at the southern tip of the Magallanes sub-Antarctic ecoregion. In this study we present an update of the avifauna records for the Gonzalo Island, Diego Ramirez Archipelago, including the first fall and winter records, and sightings at other times of year. In three expeditions, during the austral reproductive season (spring-summer, November 29-December 1, 2016), winter (July 20-22, 2017) and fall (March 28-April 1, 2018), birds were monitored using mist-nets and creating species lists from field observations. For the observations of birds throughout the year, we used the photographic records made by Jose Mella (coauthor) and Jose Mejia (Navy petty officers at Gonzalo Island Lighthouse, years 2014-2018), and new photographic records were initiated with trained personnel of the Navy of Chile in the lighthouse of Gonzalo Island. Nine of these species represent new records for the archipelago: Neotropic cormorant (Phalacrocorax brasilianus Gmelin, 1789), Western cattle egret (Bubulcus ibis (Linnaeus, 1758)), Peregrine falcon (Falco peregrinus Tunstall, 1771), Austral negrito (Lessonia rufa Gmelin, 1789), Austral thrush (Turdus falcklandii Quoy & Gaimard, 1824), Rufous-collared sparrow (Zonotrichia capensis Muller, 1776), Black-chinned siskin (Spinus barbatus Molina, 1782), Blue-and-White Swallow (Pygochelidon cyanoleuca patagonica D’Orbigni & Lafresnaye, 1837) and Black-bellied storm petrel (Fregetta tropica Gould, 1844). Some of these new records could be associated with global warming and a recent expansion of the latitudinal distribution areas and/or the residence periods of these birds. Among the 33 species, 26 were recorded in spring-summer, 22 in fall, and 14 in winter. However, nine were sighted only occasionally and it will be necessary in the future to determine whether they are resident species that are seldom observed, or occasional visitors. Regarding conservation status, according to the IUCN Red List of Threatened Species, the avifauna of the Diego Ramirez Archipelago includes an endangered species (Grey-headed albatross, Thalassarche chrysostoma Forster, 1785), three vulnerable species and four almost threatened. Monitoring on these islands provides a baseline to evaluate the status of bird populations under the threats of global change, among which the threat of invasive species is highlighted. It is critical to prevent the arrival of rats (Rattus spp.), mice (Mus musculus Linnaeus, 1758), cats (Felis catus Linnaeus, 1758), and American mink (Neovison vison Schreber, 1777), which are present in the Cape Horn Biosphere Reserve, located less than 100 km north of the Diego Ramirez archipelago . The collaborative work with the Chilean Navy has been crucial to start these long-term ornithological studies, associated with the new Long Term Socio-Ecological Studies Site Gonzalo Island-LTSER that forms part of the Chilean Long-Term Socio-Ecological Studies Network (LTSER-Chile), and the International Long-Term Ecological Studies Network (ILTER). A main goal will be to combine avifauna monitoring with detection of potential invasive species