Abstract
In the present study the diet of the barn owl Tyto alba was analysed in the ecosystem of Pampa del Tamarugal, in the Atacama Desert, northern Chile. The area is characterised by extremely dry conditions, and relatively homogeneous and poor vegetation, dominated mainly by tamarugo forests (Prosopis tamarugo). The results indicated that small mammals were the greatest proportion (76.2%) in the diet of the barn owl, which predated only four species, of which the rodent Phyllotis darwini (approximately 62%) represented the major proportion. Nevertheless, reptiles and arthropods were also relevant prey for the barn owl, with a proportion of 5% and 15.1%, respectively. The general dietary composition of the tamarugos barn owl showed a wide‐ranging diet pattern, characterised mainly by a poor diversity of small mammals and a significant consumption of reptiles and arthropods, in contrast to the sites in the central region and south Chile, where the diet included a greater diversity of small mammals, especially rodents. This pattern might reflect the conditions of extreme aridity, and low primary productivity in the ecosystem of Pampa del Tamarugal, restricting the abundance and diversity of the preferential prey (e.g. rodents). Hence, T. alba tends to increase its trophic diversity, adding other kinds of alternative prey to compensate for the low proportion of preferential prey available in the field.
Present address: Marcelo M. Rivadeneira, Section of Ecology, Behavior & Evolution, Division of Biology, University of California, San Diego, La Jolla, CA92093–0116 California, USA
Acknowledgements
The present contribution has been possible thanks to the collaboration from the Chilean National Forest (CONAF), Miguel Valdebenito (gamekeeper of the National Reserve Pampa del Tamarugal), César Cardozo, Felipe Carevic, Oscar Matus, and Alvaro Carevic. E. Ernesto Carmona, Vilma Ortiz, and Fabián Carmona provided additional logistical support and encouragement during our field trips. Jaime Rau and José Yáñez helped us with the collection of literature. Walter Sielfeld, Mark Duk, Mary K. Roberts, and one anonymous referee provided valuable suggestions to improve this contribution. We are finally thankful to Marcela Rivadeneira, and Joachim A. Prieto, for helping us with the English translation.
Notes
Present address: Marcelo M. Rivadeneira, Section of Ecology, Behavior & Evolution, Division of Biology, University of California, San Diego, La Jolla, CA92093–0116 California, USA