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Common Murre

Uria aalge
PROFILE COMU by Ram 520x289

It's true: Murres are black and white and stand up straight like penguins. But they're not closely related to penguins. In fact, penguins aren't found in the Northern Hemisphere at all. 

Murres and penguins share similar ecological roles. As diving fish-eaters, the two types of birds have similar body shapes, plumage patterns and behaviors. They are a striking example of evolutionary convergence: the comparable adaptations of disparate organisms to shared environmental pressures. 

Living in densely packed colonies offers both murres and penguins some advantages. Birds at the colony locate food sources by following the lines of returning birds. A large group can gang up on predators and collectively drive them off. Together, the birds find strength and comfort in their thronging numbers.

There are some disadvantages to colonial life, though. Slight disturbance can cause a "dread flight," triggering a chain reaction response: neighbor reacts to neighbor, on and on until thousands of murres pour pell-mell off the rocks. These chaotic flights expose murre eggs and chicks to predatory gulls, ravens, vultures, even pelicans. Bald Eagles have become notorious of late for inflicting this "dread" upon Oregon's murres, terrorizing the colonies in spring with increased frequency.

A mid-summer murre colony is a crowded and busy place. Parents zoom in after foraging, fish in beak, for invariably awkward crash landings, often right on top of other murres. Amid squawks and pokes of protest, the parents scurry off to find their chicks amid the masses. Sometimes the parent delivers a fish so large that the tail sticks out of its chick's mouth and can't be swallowed until the head is digested first.

After just three weeks, it's time for the chicks to leave the rocky cliffs. Problem is, they can't fly! The fathers call from the sea far below, urging their chicks to jump. A few chicks call back. The noise and excitement mount until chicks take a leap of faith, fluttering and splashing en masse into the ocean. 

The chicks, at only 20% of adult weight, must quickly adjust to life at sea. 

But the jumplings don't have to fend for themselves quite yet. The male swims away from the colony with his cheeping chick in tow. This pair will stay together for another 45-60 days. Soon the parent molts and is just as flightless as his chick. The father continues to feed the growing chick as they wander north to spend their flightless period in the sheltered bays and straits of Washington and southern British Columbia.  

Murres return to the same breeding colonies—to the same exact spot on the rocks, in fact—each year. They begin showing up at the colony around in Mid-march and stick around until August, when the jumplings again cast off from the rocks. 

 

 

 

Facts About Common Murre

-Each murre egg is unique in color and marking, allowing its parents to recognize their own among thousands. 

-The pointed shape of a murre’s egg prevents it from rolling off a ledge

-Due to their small wings and heavy bodies, murres require a sprint across the water's surface to reach flying speed  

-Murre excrement is rich in potash, a fertilizer, which promotes the growth of marine plants such as phytoplankton

 

Last Updated: Jun 15, 2015
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