Common Murre (Uria aalge) 



World Breeding Range 



Common Murres are some of the most 

 highly colonial of all seabirds. Island and mainland 

 colonies are usually densely packed shoulder to 

 shoulder with these noisy, gregarious birds. 

 Common Murres breed in both the North Pacific 

 and North Atlantic Oceans and are some of the 

 most abundant seabirds in the northern hemis- 

 phere. 



Common Murres prefer to nest on wide, flat 

 cliff ledges and the tops of islands. A large, single 

 egg is laid on bare rock or soil and is narrowly 

 pointed at one end and broad and rounded at the 

 other. Murre eggs vary greatly in color, ranging 

 from white to buff, brown, reddish, blue, or 

 green. They are almost always marked with dark 

 dots, blotches, or intricate scribbling (Harrison 

 1978). The unique pattern of each egg probably 

 aids individual recognition by adults (Johnson 

 1941). 



Murre chicks are fed by both parents and 

 jump from the colonies to the waters below when 

 only partly grown. They are accompanied at sea 

 by only one parent, usually the male (Varoujean 

 pers. comm.). 



Common Murres are good fliers and are 

 capable of foraging long distances from their 

 colonies. They dive to considerable depths 

 and include fish, crustaceans, and cephalopods in 

 their diet (Ogi and Tsujita 1973, 1977). Common 

 Murres are often seen in coastal California during 

 the fall and winter months (Ainley 1976) and 

 make frequent landfalls at their colonies during 

 these seasons. 



CALIFORNIA COLONIES 



In California, Common Murres breed from 



Castle Rock (325 006) in the northern part of the 

 state south to Hurricane Point Rocks (454 Oil) 

 at the north end of the Big Sur coast. They are 

 known to breed at 19 sites in California and a few 

 non-breeders have been seen on three additional 

 islands. These three islands, Kibesillah Rock (379 

 004), White Rock (379 010), and Gualala Point 

 Island (404 004), all appear to have suitable 

 nesting habitat and should be watched for future 

 nesting. 



Colonies of Common Murres, although easy 

 to find, are difficult to census. Variables such as 

 time of year, time of day, and the unknown 

 breeding status of many individuals complicate 

 an already difficult task (see Materials and Meth- 

 ods). The estimates of murre numbers presented 

 here and in the tables include the number we 

 actually counted or estimated, plus two-thirds 

 of that number to account for members of the 

 breeding pair away from the colony (Ainley 1976). 



Colonies of Common Murres in California 

 vary greatly in size, from as few as 50 birds on 

 Sisters Rocks (325 008) to 126,000 birds on 

 Castle Rock. Other large colonies of murres exist 

 at the Farallon Islands (429 012) with 60,000 

 birds, Green Rock (325 020) with 55,000 birds, 

 False Klamath Rock (325 010) with 26,500 birds, 

 and Flatiron Rock (325 023) with 24,000 birds. 



HISTORICAL STATUS AND VULNERABILITY 



Two lines of evidence suggest that Common 

 Murres are presently increasing in number in 

 California. First, in 1979 and 1980 Common 

 Murres were found breeding at four sites where 

 murres were not observed by Osborne and 

 Reynolds (1971), although they censused these 



40 



