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 penguins 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.