DISTANCE NAVIGATION IN THE ADELIE PENGUIN

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Abstract
Summary: Male Adelie penguins Pygoscelis adeliae were transported from coastal rookeries in the Ross Sea area of Antarctica to three release points on featureless ice plateaux in the interior of the continent. Birds were released individually and their departure routes mapped for distances of 2–4 km., the position of the bird being determined by triangulation every five minutes. Precise data were thus obtained on the straightness of course and direction selected by each of 103 birds.Birds released inland from a coastal rookery under favourable conditions consistently moved in straight courses N.N.E. toward the coast. Birds from the same rookery released at points to the east and west took courses essentially parallel to this departure direction, i.e., northwest and northeast respectively on a meridian scale rather than true north or in the homeward direction. These and other experiments under varying degrees of cloud cover and with birds prepared under artificial day‐night light regimes indicate that the birds possessed a navigation mechanism which used the sun as the primary orientation cue plus a biological clock to compensate for changing sun azimuth positions. The mechanism effected a consistent escape direction for birds of a given population (source) regardless of the location of the release site.The “grid N.N.E.” orientation of these birds is compared with “nonsense orientation” as described for ducks and other birds. It is considered to have survival value in the present instance in steering lost penguins to the appropriate off‐coast feeding areas and in segregating and concentrating the birds from the various circum‐continental populations.