Report on beak abnormalities of some birds of Patagonia

Avian beaks are complex and highly specialized structures that if altered could hinder many aspects of bird biology. Here, we provide evidence from incidental sightings of 24 birds from 9 species presenting a mild to severe degree of beak abnormality, including species from Passeriformes, Falconiformes, Sphenisciformes, and Charadriiformes, recorded in Chile (2013-2016). The most common alterations corresponded to crossed beaks and excessive elongation of the upper beak (25% each). The Austral Thrush (Turdus falcklandii; n = 11) and Chilean Mockingbird (Mimus thenca; n = 5) were the birds most frequently recorded with abnormalities. With the exception of the Austral Thrush and Magellanic Penguin (Spheniscus magellanicus), all beak abnormalities mentioned here are the first recorded for each species. Received 11 August 2017. Accepted 18 September 2018.