SATELLITE TELEMETRY OF THE WINTER MIGRATION OF ADELIE PENGUINS (PYGOSCELIS-ADELIAE)

Adelie penguins (Pygoscelis adeliae), after breeding in Antarctica dur ing the austral summer, undergo a winter migration before returning to the breeding grounds 8 months later. It is the major source of adult mortality, with about a quarter of them not returning. Here we describ e the first attempt to track the winter migration of Adi lie penguins using satellite telemetry. Transmitters were attached to two penguins on 16 February 1991 after their post-breeding moult at Cape Bird, Ross Island, Antarctica. Transmissions were received from one penguin (bir d #1) for 4.4 months, during which time it travelled 2792.6 km from th e rookery (nearly 1500 km straight-line distance). Transmissions were received from the other penguin (bird #2) for 2.5 months during which time it followed a path remarkably similar to that of bird #1. The pen guins travelled northwards up the coast of Victoria Land, keeping with in 100 km of the coast, rounding Cape Adare soon after 29 March and we re midway between the Balleny Islands and the Antarctic coast on 3 May . Thereafter, the record from bird #1 shows that it travelled further westwards until, when opposite the Mastusevich Glacier Tongue of the M astusevich Glacier, it turned due north and moved away from the coast. By 29 June, when transmissions ended, its progression had slowed and it was northwest of the Balleny Islands near a zone where pack ice cov ered 75% of the surface of the sea. Two novel points that arise from t his study are: (1) that Adelie penguins from Cape Bird undergo winter migrations of not less than 5000 km, and (2) that they may be travelli ng to common overwinter feeding grounds.