Foraging effort of the Magellanic Penguin from Patagonian colonies with different population trends

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

Victoria

Conferencia; 1st World Seabird Conference; 2010

1st World Seabird Conference

In long-lived species such as seabirds, quantification of foraging parameters during the breeding season should help understand population trends. We studied the foraging effort of 35 breeding Magellanic Penguins Spheniscus magellanicus from four colonies in coastal Patagonia, Argentina (42–54° S): Punta Norte (PN), Bahía Bustamante (BB), Puerto San Julián (PSJ) and Isla Martillo (IM) in an attempt to relate this to differences in breeding population trends. Penguins from BB and PN traveled, on average, significantly greater distances than those from PSJ and IM (144 and 138 vs. 101 and 78 km, respectively). Trip duration also differed between colonies, with penguins from BB spending more time at sea than those from other colonies (up to a mean of 14 hours more). The maximum distance ranged from the nest during foraging from BB and PN penguins was almost double that for PSJ and IM birds (48 and 45 vs. 32.42 and 24 km, respectively). Mean travel velocity (horizontal) was also different between colonies with the individuals from PN moving slowest (1.16 m/s) while those from PSJ being the fastest (2.08 m/s). In all cases, the total trip length was a good indicator of trip duration. This information, coupled with indicators of prey consumption rates from these birds, suggests that there are large differences in foraging effort and success between Patagonian penguin colonies with penguins from BB being worst off.