17 JANUARY 1998. CHILE: SEABIRDS

Chanaral Island, 26o-32oS 72oW: We used satellite telemetry on 5 Humboldt penguins from Isla Pan de Azucar (26oS, 72oW) since November 1997 in an ongoing experiment to determine foraging activities and at sea distribution. All equipped birds were breeders in November, but judging from the duration and extent of their foraging trips, had given up breeding in early December 1997. This may be related to high sea water temperatures, which currently are ca. 3oC above normal in that area. Two birds are still being tracked and have moved South to about 32oS, which corresponds to a distance of 600 km from their breeding island.

While our earlier data suggested that Humboldt penguins from Isla Pan de Azucar migrate during the winter months, the new results provide support to our hypothesis that these birds are definitely not sedentary, but able to react to unfavourable environmental conditions by migration.

We also investigated Humboldt penguins at their most southerly known breeding location, Islotes Punihuil (42oS) using VHF-telemetry and TDRs. So far, we found that foraging range and at sea activities are similar to those of northern birds during non-ENSO years. Again, all equipped penguins were breeders in November 1997, but as opposed to Isla Pan de Azucar birds, are doing well and raising healthy chicks up to the present. According to NOAA, sea water temperatures at 42oS are near normal."--Boris Culik and Janos Hennicke <bculik@ifm.uni-kiel.de>