fauna is diverse, only a few species make up the 

 majority of this assemblage of seabirds. Common 

 Murres, Brandt's Cormorants, Cassin's Auklets, 

 and Western Gulls compose almost 90 percent of 

 the California population (Figure 2). A dispro- 

 portionately large percentage of this population 

 breeds at only a few locations in the state. Two 

 regions, the Farallon Islands and the north coast 

 of California from Cape Mendocino to the Oregon 

 border, contain the largest number of breeding 

 seabirds (Figure 3). The Farallon Islands are 

 extremely important. Large portions of the 

 state's breeding populations of Ashy Storm-Petrels, 

 Brandt's Cormorants, Western Gulls, Common 

 Murres, Pigeon Guillemots, Cassin's Auklets, 

 Rhinoceros Auklets, and Tufted Puffins breed 



on these islands (Figure 4). 



The coastline north of Cape Mendocino 

 contains more breeding seabirds than the Farallon 

 Islands although no single site there approaches 

 the Farallones in number of birds. Large portions 

 of the state's breeding population of Fork-tailed 

 Storm-Petrels, Leach's Storm-Petrels, Double- 

 crested Cormorants, Common Murres, Rhinoceros 

 Auklets, and Tufted Puffins inhabit this coast. 

 Castle Rock (325 006), the second-largest seabird 

 colony in the state, is found in this stretch of 

 coastline. 



The Channel Islands are particularly note- 

 worthy since the entire California breeding 

 populations of Black Storm-Petrels, Brown 

 Pelicans, and Xantus' Murrelets nest there. The 



Common Murre 

 '363,154 



,(53%) 



Brandt' 



Cormorant 



1 1 1 1 M i 



64,210 



1(9%) 



Figure 2. Populations of breeding seabirds and per- 

 cents of total aggregate population in California. 



Loach's Slorm-Petrel 18,304 ( 370 

 Pelagic Cormorant 15.870(2'-) 

 Pigeon Guillemot 14.724 (2%) 



Fork -tailed Storm-Petrel 

 Ashy Storm-Petrel 

 Black Storm-Petrel 

 Brown Pelican 

 Double-crested Cormorant 

 Black Oystercatcher 

 Forster's Tern 

 Least Tern 

 Elegant Tern 

 Caspian Tern 

 Black Skimmer 

 Marbled Murrelet 

 Xantus' Murrelet 

 Rhinoceros Auklet 

 Tufted Puffin 



* coastal population only. 



(4%) 



12 



