Under these drastically changing conditions, the struggle to survive favored the larger birds with deep, strong beaks for opening the hard seeds. Smaller finches with less-powerful beaks perished.

Biermann, W. H., and Voous, K. H., Birds Observed and Collected during the Whaling Expeditions of the Willem Barendsz in the Antarctic (1946–1947 and 1947–48).

Atlantic puffins’ beaks are more reminiscent of birds that live in the rainforest than on chilly cliffs. Bright orange or red, with blue and white streaks, it’s obvious why they’ve been ...