Flexible foraging for finding fish: variable diving patterns in Magellanic penguins from different colonies

SALA, J. E; WILSON, R.P.; FRERE, E.; QUINTANA, F.

Journal of Ornithology

Springer

Lugar: Berlin; Año: 2014 p. 1 - 19

2193-7192

Seabirds have to deal with environmental variability and are predicted to modulate foraging behaviour to maximize fitness, with particularly strong selection pressure for optimal behaviour during chick provisioning when energy demands are high. We reported data from 42 breeding birds equipped during the early chick-rearing period with depth recorders at four different colonies [Punta Norte (42°S), Bahía Bustamante (45°S), Puerto Deseado (47°S) and Puerto San Julián (49°S)] in patagonian Argentina. Although Magellanic penguins are purported to show little flexibility in foraging behaviour, we discovered marked inter-colony differences in diving behaviour. Even though the southern marine ecosystems, in general, and the area exploited by Magellanic penguins from the studied colonies in particular, are usually characterized by their stability we can not exclude entirely that interannual differences may have also affected our results The colonies located in the centre of breeding distribution, Bahía Bustamante and Puerto Deseado, showed the greatest diving and foraging effort with Bahía Bustamante penguins having the deepest and longest dives of all birds and requiring the longest post-dive recovery durations at the surface. Puerto Deseado had the birds with the highest values of diving effort parameters. Penguins from both colonies also had the highest descent and ascent rates during dives. We assume that the clear variation in diving behaviour reflects the response of the birds to the varying prey types and availability around the different colonies but note that, despite this, some colonies fare markedly better than others in breeding.