Common murre (Uria aalge)
The common murre is one of several similar birds, collectively called auks, which are known as the penguins of the north for their upright posture on land and black-and-white feathers. Like penguins, the murres legs are placed far back on its body, enhancing swimming ability but at the cost of poor walking skills. The common murre occurs in the north Pacific and north Atlantic oceans.
This auk is easily differentiated from other species by its large size of about 17 inches, narrow, long bill and white chest and belly. The head is all black during the summer breeding season, changing in winter to a black cap, white cheeks with a dark stripe from the eye and a white throat.
The common murre roost in dense colonies on isolated rocks or cliffs, where they are protected from land predators. They nest in similar isolated rocky sites where they lay eggs on the surface of the rock. Like other rock nesting birds, one end of the egg is much narrower than the other to allow the egg to roll in a tight circle, reducing chances of egg loss. The young are raised at the nest until they are half-grown, by which time they go to sea with the male, where they continue to be fed.
Common murre feed in open water, where they regularly dive to depths of 300 feet, catching fish and crustaceans. They use their wings to fly underwater. Because they spend so much time at sea, they are common victims of oil spills.
David W. Jamison is a marine biologist and Boston Harbor resident.