Acoso cooperativo y usurpación de cavidades por Sturnus vulgaris, costo reproductivo para Colaptes melanochloros

GERSTMAYER PAULA; MONGES VIRGINIA; JAUREGUI ADRIÁN; COLOMBO MARTIN; SEGURA LUCIANO

Gramado

Congreso; II Congreso de Ornitología de las Américas; 2023

The European Starling (Sturnus vulgaris) is a cavity-nesting bird with great invasive potential. It iscurrently distributed across all continents (except Antarctica) and its distribution range isincreasing at an alarming rate. It was introduced to Argentina in 1983 and is now widespread in thecentral region of the country. Considered one of the hundred most damaging invasive speciesglobally, it poses a serious competitive threat to cavity-nesting birds. Interactions betweenEuropean Starlings and cavity-nesting birds generally have negative consequences for native birdpopulations, although there are still few reports that account for the degree of damage. In thisstudy, we present the first detailed account of the cooperative harassment strategy and subsequentcavity usurpation by European Starlings on a breeding pair of Green-barred Woodpeckers(Colaptes melanochloros) in an urban area of central-eastern Argentina. Throughout a singlebreeding season, the woodpeckers excavated seven cavities, none of which were successful. In sixof these reproductive attempts (86%), we documented interactions with European Starlings and infive (71%), the cavity was usurped. We observed the cooperative harassment strategy on threeoccasions. Our report is particularly significant when considering the global invasive potential ofthe European Starling and the limited availability of cavities in the breeding habitats of nativebirds. If we extrapolate this cooperative agonistic behavior to the reproductive habitats of nativecavity nesting species with a threat category, the consequences could be extremely serious.