Alta mortalitat d'hirundínids a les carreteres del delta de l'Ebre i rodalies la primavera de 1992

• Autores: Joan Estrada, Xavier Rivera
• Localización: Butlletí del Grup Català d'Anellament, ISSN 1130-2070, Vol. 12, Nº. 1, 1995, págs. 17-22
• Idioma: catalán
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• Resumen

  • Swallows and rnartins are cornrnonly seen to fly at ground level, capturing insects close to roads, but according to literature casualites in these species are low. Contrary to that view, we report two instances of high rnortality. Results are based on three counts of birds found dead, struck by cars, on the roads in and around the Ebro Delta (Catalonia, NE Spain) in spring 1992. In total, 529 casualties were collected, of which 97% were Hirundinidae. This fact is connected herein with adverse weather conditions, which rnight have caused a regression of the muscle tissue. Such regression of the muscle tissue would irnply a decrease in the flight capability that is needed in order to be able to dodge cars, and the birds would thus becorne highly vulnerable.