Colisiones de aves contra ventanales en un campus universitario de Bogotá, Colombia

Collisions of birds with windows on a university campus in Bogotá, Colombia

Abstract

Land transformation and the accelerated rate at which cities are growing have generated new conservation problems that have not been studied thoroughly in the tropics. This is the case of bird collisions with human built structures, estimated to claim billions of victims every year around the world. Between April 2006 and November 2008, we recorded collisions of 106 individuals of 18 species, including 11 species of boreal migrants and 7 resident species, with windows of six buildings in the campus of the Pontificia Universidad Javeriana in Bogotá; 88% of all collisions were fatal to the birds. We found that windows through which birds could see vegetation beyond were more dangerous (73% of all collisions recorded) than those which simply reflected vegetation or the sky, and that the number of collisions peaked during the period of fall migration by boreal breeders. Extrapolating our study of collisions at six buildings, we estimate that ca. 271 collisions could occur annually over the entire campus. We invite others to extend these observations and to collect as scientific specimens the casualties so they can serve as a source of information on patterns of migration, expansion of distribution ranges and potential national and global threat for some species. We review possible mitigation measures and encourage others to apply and evaluate those that have proved effective elsewhere.