Breeding biology and nest site characteristics of the White-throated Hawk (Buteo albigula) in northwestern Argentine Patagonia

TREJO, A., V. OJEDA, L. SYMPSON Y M. GELAIN

Journal of Raptor Research

Raptor Research Foundation

Lugar: Lawrence, Kansas, USA; Año: 2004 vol. 38 p. 1 - 8

0892-1016

We studied the breeding biology of the White-throated Hawk (Buteo albigula) in Nothofagus forests of northwestern Argentine Patagonia. We documented 11 nesting attempts from September to April 1998–2002, and recorded behavioral observations at two nests during the 2001–02 breeding season. After the hawks arrival in the area in mid-September, the pre-laying period extended approximately until early November (ca. 1.5 mo). Laying at two nests occurred between 10 and 15 November. Incubation lasted until 15–17 December (ca. 1 mo). The brood rearing period (ca. 40 d) extended until late January, when fledging was observed. However, in one nest in the 2000–01 season, we found a small chick on 13 January that fledged about 20 February, which suggests that some late breeding attempts can be successful. Females performed most of the incubation. Pairs produced only one fledging per successful nest, but we observed two nestlings during the early brood-rearing stage at one nest. Both sexes defended nests against intruders. Males delivered all of prey brought to the nests during incubation, and 80% of food delivered during the nestling period. Birds, rodents, and lizards were the most numerous prey brought to nests. White-throated Hawk nests were platforms made of dry and green sticks located at a mean height of 16 m above the ground in Nothofagus trees that averaged 0.8 m in diameter at breast height. forests of northwestern Argentine Patagonia. We documented 11 nesting attempts from September to April 1998–2002, and recorded behavioral observations at two nests during the 2001–02 breeding season. After the hawks arrival in the area in mid-September, the pre-laying period extended approximately until early November (ca. 1.5 mo). Laying at two nests occurred between 10 and 15 November. Incubation lasted until 15–17 December (ca. 1 mo). The brood rearing period (ca. 40 d) extended until late January, when fledging was observed. However, in one nest in the 2000–01 season, we found a small chick on 13 January that fledged about 20 February, which suggests that some late breeding attempts can be successful. Females performed most of the incubation. Pairs produced only one fledging per successful nest, but we observed two nestlings during the early brood-rearing stage at one nest. Both sexes defended nests against intruders. Males delivered all of prey brought to the nests during incubation, and 80% of food delivered during the nestling period. Birds, rodents, and lizards were the most numerous prey brought to nests. White-throated Hawk nests were platforms made of dry and green sticks located at a mean height of 16 m above the ground in Nothofagus trees that averaged 0.8 m in diameter at breast height. forests of northwestern Argentine Patagonia. We documented 11 nesting attempts from September to April 1998–2002, and recorded behavioral observations at two nests during the 2001–02 breeding season. After the hawks arrival in the area in mid-September, the pre-laying period extended approximately until early November (ca. 1.5 mo). Laying at two nests occurred between 10 and 15 November. Incubation lasted until 15–17 December (ca. 1 mo). The brood rearing period (ca. 40 d) extended until late January, when fledging was observed. However, in one nest in the 2000–01 season, we found a small chick on 13 January that fledged about 20 February, which suggests that some late breeding attempts can be successful. Females performed most of the incubation. Pairs produced only one fledging per successful nest, but we observed two nestlings during the early brood-rearing stage at one nest. Both sexes defended nests against intruders. Males delivered all of prey brought to the nests during incubation, and 80% of food delivered during the nestling period. Birds, rodents, and lizards were the most numerous prey brought to nests. White-throated Hawk nests were platforms made of dry and green sticks located at a mean height of 16 m above the ground in Nothofagus trees that averaged 0.8 m in diameter at breast height. Buteo albigula) in Nothofagus forests of northwestern Argentine Patagonia. We documented 11 nesting attempts from September to April 1998–2002, and recorded behavioral observations at two nests during the 2001–02 breeding season. After the hawks arrival in the area in mid-September, the pre-laying period extended approximately until early November (ca. 1.5 mo). Laying at two nests occurred between 10 and 15 November. Incubation lasted until 15–17 December (ca. 1 mo). The brood rearing period (ca. 40 d) extended until late January, when fledging was observed. However, in one nest in the 2000–01 season, we found a small chick on 13 January that fledged about 20 February, which suggests that some late breeding attempts can be successful. Females performed most of the incubation. Pairs produced only one fledging per successful nest, but we observed two nestlings during the early brood-rearing stage at one nest. Both sexes defended nests against intruders. Males delivered all of prey brought to the nests during incubation, and 80% of food delivered during the nestling period. Birds, rodents, and lizards were the most numerous prey brought to nests. White-throated Hawk nests were platforms made of dry and green sticks located at a mean height of 16 m above the ground in Nothofagus trees that averaged 0.8 m in diameter at breast height.