BREEDING BIOLOGY OF THE SOUTHERN GIANT PETREL

SOFÍA COPELLO; FLAVIO QUINTANA

ORNITOLOGIA NEOTROPICAL

NEOTROPICAL ORNITHOLOGICAL SOC

Año: 2009 p. 369 - 380

1075-4377

The Southern Giant Petrel (Macronectes giganteus) is a wide ranging procellariiform considered Near Threatened under IUCN criterion. The Agreement for the Conservation of Albatrosses and Petrels (ACAP) encourages the research on the breeding biology of listed threatened species such as the giant petrels. Better understanding of this issue will help in the development of conservation tools. From 2001 to 2005 we studied aspects of the breeding biology of the Southern Giant Petrel from north colonies of Patagonia, Argentina. Breeding adults arrived at the colonies during the first week of October and egg-laying began three weeks later. Hatching was synchronous and took place primarily during the third week of December. Chicks started to fledge during the second week of March through late April. Breeding success was high, with no differences between seasons (> 88%). Chick survival was 100% from age 45 days onward. The sex ratio at fledging did not differ from parity over the study period. Sexual dimorphism (with males larger than females) was apparent for body mass, bill and tarsus lengths, and bill depth. Growth rates were similar between sexes for bill, tarsus and wing lengths, and bill depth. However, the asymptotic values of these variables were different between sexes (except for wing length). The high breeding success and chick survival, the similarity in growth rates between sexes, and the evenness in the sex ratio at fledging, suggested that food resources were not a constraint in the reproduction of this species in north Patagonian colonies during the study period. high breeding success and chick survival, the similarity in growth rates between sexes, and the evenness in the sex ratio at fledging, suggested that food resources were not a constraint in the reproduction of this species in north Patagonian colonies during the study period.Macronectes giganteus) is a wide ranging procellariiform considered Near Threatened under IUCN criterion. The Agreement for the Conservation of Albatrosses and Petrels (ACAP) encourages the research on the breeding biology of listed threatened species such as the giant petrels. Better understanding of this issue will help in the development of conservation tools. From 2001 to 2005 we studied aspects of the breeding biology of the Southern Giant Petrel from north colonies of Patagonia, Argentina. Breeding adults arrived at the colonies during the first week of October and egg-laying began three weeks later. Hatching was synchronous and took place primarily during the third week of December. Chicks started to fledge during the second week of March through late April. Breeding success was high, with no differences between seasons (> 88%). Chick survival was 100% from age 45 days onward. The sex ratio at fledging did not differ from parity over the study period. Sexual dimorphism (with males larger than females) was apparent for body mass, bill and tarsus lengths, and bill depth. Growth rates were similar between sexes for bill, tarsus and wing lengths, and bill depth. However, the asymptotic values of these variables were different between sexes (except for wing length). The high breeding success and chick survival, the similarity in growth rates between sexes, and the evenness in the sex ratio at fledging, suggested that food resources were not a constraint in the reproduction of this species in north Patagonian colonies during the study period. high breeding success and chick survival, the similarity in growth rates between sexes, and the evenness in the sex ratio at fledging, suggested that food resources were not a constraint in the reproduction of this species in north Patagonian colonies during the study period.