CADIC   02618
CENTRO AUSTRAL DE INVESTIGACIONES CIENTIFICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Foraging behaviour during chick rearing of sympatrically breeding Humboldt and Magellanic penguins in southern Chile
Autor/es:
A RAYA REY; K PÜTZ; L HIRIART BERTRAND; A SIMEONE; R REYES ARRIAGADA; V RIQUELME; B LÜTHI
Lugar:
Boston USA
Reunión:
Conferencia; VII International Penguin Conference; 2010
Resumen:
Humboldt and Magellanic penguins breed sympatrically at Puñihuil Islets in Chile. As these are two closely related species with comparable food requirements, we studied the degree of resource partitioning. Sex- and species-specific foraging areas and diving behaviour were investigated during the chick-rearing period using GPS-TDlog and TDRs. Penguins performed mainly daily foraging trips close to the colony. Maximum distance to the colony did not significantly differ between species and sexes (average 8.8 ± 3.2 km). Foraging trip and diving characteristics also revealed no significant interspecific differences. The major differences observed were sex-specific, independently of species. Trip duration (range: 2.3 to 26 hs) was shorter in females while the diving rate (range: 13 to 48 dives per hour) was higher than in males. Mean dive duration (range: 45 to 91sec) was higher in males than in females which is in accordance with the slight sexual dimorphism found in these species. Mean dive depth ranged from 9 to 37 m, maximum depth attained was 70 meters and maximum dive duration recorded was 270 s. Interestingly, all birds showed a high value of intra depth zone dives (more than 70%), indicative of benthic feeding. In contrast to these findings, previous studies indicated a high amount of pelagic fish in their diet. Magellanic penguin’s males performed less intra depth zone dives, this being the only sex-species difference. In conclusion, in areas where food is not limited, variations in the diving behaviour are likely to be more sex-specific rather than interspecific.