Abstract

FIGUEROA ROJAS, Ricardo A.; CORALES STAPPUNG, E. Soraya  and  ALVARADO O., Sergio. Diet of the Red-backed Hawk (Buteo polyosoma) in a forested area of the Chilean Patagonia and its relation to the abundance of rodent prey. Hornero [online]. 2003, vol.18, n.1, pp.43-52. ISSN 0073-3407.

The diet of Red-backed Hawk (Buteo polyosoma) was quantified by analyzing 40 pellets collected during winter and spring 1999 and winter 2000 in a forested area of Aysén, Chilean Patagonia. Rodents were the most numerous prey (82% of all prey), and accounted for the highest contribution to total biomass (83%). Among rodents, Oligoryzomys longicaudatus was the most consumed prey species, accounting for 70% of total number and 64% of total biomass. Birds accounted for less than 6% in number, but their biomass contribution was significantly higher (more than 15%). Insects constituted 12% in number, but less than 0.5% of total biomass. The Red-backed Hawk seemed to consume Oligoryzomys longicaudatus according to their field abundance. Also, it seemed to prey disproportionately upon young adult rodents. Relating these results with previous studies on the same species, we conclude that this hawk mostly predates upon vertebrate species throughout its distribution range, with rodents being the most important prey.

Keywords : Buteo polyosoma; Chilean Patagonia; diet; Oligoryzomys longicaudatus; prey selection; Red-backed Hawk.

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