Gentoo penguins outweigh their neighbors by more than a kilogram

How different are the three Palmer Archipelago penguin species? Each row is one penguin measured near Palmer Station, Antarctica, from 2007 to 2009.

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Every measurement at a glance

The summary profiles each field: its range, its typical value, and how many birds are missing it.

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Not every species lives on every island

Gentoo penguins appear only on Biscoe and Chinstraps only on Dream; Adélies live on all three islands. Any island comparison is partly a species comparison.

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Longer flippers, heavier birds

Across all three species, flipper length tracks body mass closely: flipper length and body mass had correlation 0.871. Within each species the fitted line is shallower than the trend across all three, and Gentoos sit apart at the top right. The heaviest bird weighed 6,300 g, a male Gentoo from Biscoe.

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Gentoos weigh a kilogram more

The boxes barely overlap. Gentoo penguins averaged 5,076 g. Adélie penguins averaged 3,701 g, and Chinstrap penguins averaged 3,733 g, so the two smaller species are within 32 g of each other while Gentoos carry 1.4 kg more.

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Takeaway

Adélie and Chinstrap penguins are close in weight; Gentoos are heaviest and have the longest flippers, though Chinstraps have the longest bills. Because each species keeps to its own islands, separate species from place before comparing islands.

Limits

344 birds from three seasons, with 11 of unrecorded sex. Body mass changes through the breeding season, and birds were weighed at different stages.