Chapter 1 



Natural History of the Common Murre 

 (Uria aalge californica) 



by 

 David A. Manuwal 1 and Harry R. Carter 



'University ofWoshington, College of Forest Resources 



Wildlife Science Group 

 Seattle, Washington 98195 



-Humboldt State University; Department of Wildlife 

 Arcata, California 95521 



Abstract: This natural history of the common murre ( Uria aalge californica) in California. Oregon. Washington, 

 and British Columbia was summarized from published and unpublished information. This information was 

 augmented with results from studies conducted in the North Atlantic and Alaska. Substantial information on 

 breeding biology was obtained at the South Farallon Islands in central California, and additional studies at 

 Tatoosh Island. Washington, and Triangle Island, British Columbia. Little demographic information was 

 available from banded populations, except at the South Farallon Islands. At-sea distribution and diet have 

 been studied widely in California, Oregon. Washington, and British Columbia, but data were available for 

 only a few years in many locations. 



Common murres breed in dense colonies on the surface of rocky islands or on cliff ledges. Breeding sites 

 are inaccessible to predatory land mammals and have low levels of human disturbance. Murres lay a single, 

 large, pointed egg on the ground, and can lay a replacement egg if the first egg fails to hatch. The egg is 

 incubated by both parents for 32-33 days. The chick is attended (brooded for the first few days) and fed by 

 both parents for its first 23-24 days before it jumps into the ocean accompanied by the male parent. The 

 parent-chick pair swims away from the colony and the chick is further raised at sea for 1-2 months by the 

 male. At-sea chick rearing overlaps with the flightless, prebasic molt for male parents, but not for female 

 parents or subadults. 



Egg laying occurs earliest (late April to early June) in California and Oregon, and later (late May to 

 mid- August) in Washington and British Columbia. Colony attendance patterns during the prebreeding period, 

 and early or late portions of the breeding period, tend to be more variable than between peak egg laying and 

 peak fledging. In California, murres sporadically attend colonies in winter, and also attend colonies earlier in 

 the prebreeding period than in Oregon, Washington, and British Columbia. Murres typically return to attend 

 natal colonies and breed in the same locations each year. Subadult murres visit natal colonies for several years 



Suggested citation: 



Manuwal. D. A., and H. R. Carter. 2001. Natural history of the common murre (Uria aalge californica). Pages 1-32 in D. A. 

 Manuwal. H. R. Carter. T. S. Zimmerman, and D. L. Orthmeyer. editors. Biology and conservation of the common murre in 

 California, Oregon. Washington, and British Columbia. Volume 1 : Natural history and population trends. U.S. Geological Survey. 

 Biological Resources Division. Information and Technology Report USGS/BRD/ITR2000-0012. Washington. D.C. 



