Puffins’ and guillemots’ eyes, new research

This 2009 video says about itself:

In Iceland‘s remote Westman Islands, warming weather is threatening a beloved mascot: the Atlantic puffin.

From Ibis, international journal of avian science:

The visual fields of Common Guillemot Uria aalge and Atlantic Puffin Fratercula arctica: foraging, vigilance and collision vulnerability

Graham R. Martin and Sarah Wanless

Summary

Significant differences in avian visual fields are found between closely related species that differ in their foraging technique. We report marked differences in the visual fields of two auk species.

In air, Common Guillemots Uria aalge have relatively narrow binocular fields typical of those found in non-passerine predatory birds. Atlantic Puffins Fratercula arctica have much broader binocular fields similar to those that have hitherto been recorded in passerines and in a penguin.

In water, visual fields narrow considerably and binocularity in the direction of the bill is probably abolished in both auk species. Although perceptual challenges associated with foraging are similar in both species during the breeding season when they are piscivorous, Puffins (but not Guillemots) face more exacting perceptual challenges when foraging at other times when they take a high proportion of small invertebrate prey.

Capturing this prey probably requires more accurate, visually-guided bill-placement and we argue that this is met by the Puffin‘s broader binocular field, which is retained upon immersion; its upward orientation may enable prey to be seen in silhouette. These visual field configurations have potentially important consequences that render these birds vulnerable to collision with human artefacts underwater, but not in air. They also have consequences for vigilance behaviour.