The Halley Bay emperor colony fails and does not recover

node

The fast ice under one of the largest and apparently most stable emperor penguin colonies breaks out before the chicks can fledge, and does so again in following seasons. Numbers at the nearby Dawson-Lambton colony rise over the same period. The episode establishes two things at once: that a colony can be destroyed by a single ice season, and that emperors will relocate rather than simply die - which makes the species' prospects a question about where suitable fast ice will still exist, not only about how much.

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