Emperor penguin foraging behavior in the western Ross Sea, 1992 GERALD KOOYMAN, MARKUS HORNING, PAUL PONGANIS, TORY KOOYMAN, and CARsTEN KOOYMAN, Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093-0204 YvEs CHEREL, Laboratoire dEtude des Regulations Physiologiques, Centre National de la Recherche Scientifique, Strasbourg, France

ost of the emperor penguin colonies in the Ross Sea about the same and averaged about 200 km. Mwere not discovered until the 1960s. Since that time, • The foraging areas for all colonies were distinct, except they have been visited sporadically except for Cape Washing- Cape Roget and Coulman Island, which overlapped (see ton, which has been studied intensively by Gerald Kooyman Ancel et al. 1992 for Cape Washington). since 1986. In 1990, Gerald Kooyman and Paul Ponganis • Census of the chicks indicated a very successful year with stayed overnight at Cape Roget and for a week at Coulman little early-season chick mortality. The Cape Roget popula- Island. These preliminary visits provided the needed informa- tion was constant from the 1990 count, but both Cape tion about the sites to begin a program of study at these Washington and Coulman Island continue to increase colonies that is similar to the research at Cape Washington. (Kooyman and Mullins 1990). There were nearly 35,000 The goal was to study foraging behavior simultaneously at chicks fledging from Coulman Island, and at Cape Wash- these three major colonies and to obtain some related infor- ington, there were over 26,000. mation about Cape Crozier. Because of logistic limitations, • Additional observations at Cape Washington were made studies were done only at Cape Washington and Coulman on leopard seal predation, killer whale behavior, and, for Island. This was the first time an extended stay was made at the first time, the extended presence of bottlenose whales. Coulman Island, and it was observed that weather there Ice-edge behavior of penguins at Coulman Island was also severely limits outdoor activity. Weather at both Coulman occasionally noted when weather permitted. Island and Cape Washington was recorded every 10 minutes This work was supported by a Creative Scientist exten- with a semiautomatic weather station. sion award to Gerald Kooyman from the National Science The objectives were to compare the foraging traits Foundation OPP 87-15863. We are especially grateful to Neil between the two colonies, to determine the distribution of Swanberg, Dave Bresnahan, and Rick Campbell who helped foraging birds from four colonies (Cape Washington, Coul- to make this complex air support program work in the face of man Island, Cape Roget, and Cape Crozier) in the Ross Sea, some serious and unplanned scheduling limits. As in the past, and to census all colonies. Weather and flight scheduling pre- the Italian Antarctic program provided us with some reassur- vented overflights of Beaufort and Franklin Islands. Otherwise ing communications back-up. The Antarctic Support Associ- all tasks were completed. ates staff, led by Steve Kottmeier, Kristen Larsen, Jill Foraging and distribution data were obtained with time- Vereyken, and Kirk Kiyota were of great help in support of the depth and satellite transmitters attached to the birds. field camps, the Cape Crozier traverses, and the McMurdo Detailed analyses of the data are not complete, but some of ice-edge studies. the salient features are as follows: • General foraging patterns of birds from Cape Washington References and Coulman Island are similar. Ancel, A., G.L. Kooyman, P.J. Ponganis, J.-P. Gendner, J. Lignon, X. • Foraging trips last about 7 to 15 days. Mestre, N. Hum, P.H. Thorson, P. Robisson, and Y. Le Maho. 1992. • Diving depths ranged broadly from near the surface to 500 Foraging behaviour of emperor penguins as a resource detector in meters (m). All birds engaged in several deep diving bouts winter and summer. Nature, 360, 336-339. in excess of 400 m during the foraging trip. Kooyman, G.L., and J.L. Mullins. 1990. Ross Sea emperor penguin • The Coulman Island birds appeared to make more deep breeding populations estimated by aerial photography. In K.R. Kerry and G. Hempel (Eds.), Antarctic ecosystems: Ecological dives. change and conservation. Berlin/ Heidelberg, Germany: Springer- • Maximum distance traveled from the four colonies was Verlag.

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