Appearance
Male and female Adélie penguins are hard to tell apart, but aggressiveness, courtship displays, copulatory positions and incubation routines are useful clues.
Adults |
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Adults have a black head with white eye ring. The back is black with blue-tipped feathers. The chest is white, feet grey-pink and the bill red. Adélies weigh between 4 and 6 kg (average weight is 4.4 kg), although males are usually slightly heavier. The birds stand about 71 cm tall. |
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Immature (first-year) birds |
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Immature birds are similar to adults except that their backs are bluer and cheeks and throat are white. Adult plumage is attained in the second year.
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Chicks |
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Chicks have sooty-blackish heads and grey down-covered bodies. Although not waterproof, the down provides good insulation for the chicks on land. | |
| Chicks develop thicker, 'woolly', dark-grey down after 10 days. |  |
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Moulting |
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As the chicks develop they loose their soft down, which is replaced by waterproof feathers. After 50 days the birds are nearly fully feathered. | |