Common guillemot (Uria aalge)
Size: 38 – 41 cm
Population at Anda: 30 pairs
Guillemots lay one egg on narrow and sloping bare cliffs, on Anda Island, all 30 pairs are nesting side by side in a small and tight cavity. In spite of the sloping cliffs, the eggs do not roll off the cliffs because they have an elliptic shape with a more pointed and narrow end. Such top-shaped eggs are advantageous when nesting on bare cliffs because when disturbed, the eggs tend to roll in circles rather than away from the nest and off the cliffs.
The bridled or also called the ringed guillemot is colour modification of the guillemot. These guillemots have a white eye ring, which extends behind the eye, and they are also darker in their color pattern than the usual form of guillemots. Bridled guillemots are not considered a subspecies but just an example of dimorphism of the common guillemot.