BIOLOGY AND CONSERVATION OF THE COMMON MURRE 39 



Few other islands in central and northern California 

 were large enough for occupation by settlers (see 

 Appendix I), but many colonies were accessible to 

 people with small boats. Several colonies may have 

 been extirpated during this period by egging and other 

 activities. However, only the loss of colonies at Prince 

 Island (c. 1912) and San Pedro Rock (c. 1908) are well 

 documented. Egging was documented at other colonies, 

 including the North Farallon Islands in the 1880s and 

 1890s. Point Reyes in 1897. and possibly Mendocino 

 County in 1900. Egging probably occurred at colonies 

 near settlements at Trinidad and Crescent City. In 

 addition to egging, extensive disturbance and human 

 access resulting from construction and operation of the 

 Ocean Shore Railroad may have contributed to the loss 

 of the San Pedro Rock colony. Similarly, egg gathering 

 for private collections may have contributed to the loss 

 of the Prince Island colony, the only location in southern 

 California where murre eggs were known to be collected 

 between 1885 and 1912. Extensive oil pollution in the 

 early twentieth century probably affected all colonies 

 in central California. Colonies in northern California 

 also may have been affected by oil pollution, judging 

 by observations of oiled murres on beaches in 1909-10 

 (C. I. Clay, unpublished field notes). Other murre colonies 

 may have been extirpated by eggers or others before 

 documentation in the Channel Islands and throughout 

 the coasts of San Luis Obispo, Monterey, Sonoma and 

 Mendocino Counties where appropriate breeding 

 habitats exist. Murres were rarely seen in southern 

 California before the 1960s until populations in central 

 California began to increase, with some murres moving 

 south after breeding (Pyle 1953; Unitt 1984: Lehmann 

 1994: Manuwal and Carter 2001). 



The murre population in northern California seems 

 to have increased markedly from the 1940s to the late 

 1970s following earlier decreases that resulted from 

 activities of early settlers and use of certain islands by 

 native people. A small colony was reported at Castle 

 Rock between 1917 and 1935. but the population 

 increased to 5.000-10.000 breeding pairs in 1956-61 

 and to 20,000-40.000 breeding pairs in 1970. In 1980. 

 Castle Rock was included in the National Wildlife 

 Refuge System. Increases at Castle Rock in the 

 mid-twentieth century appear to reflect growth and 

 recovery following use by native peoples, egging, and 

 the use of the island for grazing by domestic animals. 

 At Whaler Island, near Crescent City, breeding was 

 documented in 1928. Since 1939. the island was partly 

 quarried and a breakwater has connected it to the 

 mainland allowing easy access by rats and humans, 

 which has prevented breeding by most seabirds. Murres 

 did not breed at Flatiron Rock from 1910 to 1934. but 



1.000 breeding pairs were noted in 1969 and many 

 thousands currently breed there. This colony is close to 

 the long-settled port of Trinidad and would have been 

 very accessible to commercial eggers by boat and native 

 people by canoe (see Appendix I: Figure 1-15). In fact, 

 large numbers of eggs were collected in 1897-1901 

 from several unidentified islands, apparently in the 

 Trinidad area, indicating that higher population levels 

 may have existed at that time. Nearby Green Rock 

 seemed to be the only murre colony that existed in the 

 Trinidad area from 1917 to 1941, with about 2.000 birds 

 noted in 1941 . By 1969-70. murres were found at most 

 colonies where they have been recorded regularly since 

 1979 (except for Mendocino County), indicating 

 population increase between the 1940s and late 1960s. 



Prior to the 1 980s. certain California murre colonies 

 outside of the Farallon and Castle Rock National 

 Wildlife Refuges were protected within the Point Reyes 

 National Seashore (i.e.. Point Reyes. Point Resistance, 

 Millers Point Rocks, and Double Point Rocks), Redwood 

 National Park (i.e.. False Klamath Rock and Sister 

 Rocks), and Channel Islands National Park (i.e.. Prince 

 Island) in 1968, 1972, and 1980. respectively. Earlier. 

 Prince Island had received partial protection when 

 reserved for lighthouse purposes in 19 1 7 and transferred 

 to the U.S. Navy in 1934. Additional protection for 

 murre colonies after 1980 in California are mentioned 

 later in this chapter. 



Current Population Size and Distribution of 

 Breeding Colonies in California 



By 1995, 26 murre colonies had been described in 

 California, including 22 colonies used between 1979 

 and 1995 and 4 colonies extirpated earlier in the 

 twentieth century (Appendixes B-D). The colonies 

 separate into two groups: the northern California group 

 consisting of 15 colonies in Del None. Humboldt. and 

 northern Mendocino Counties (Figure 2.1); and the 

 central California group consisting of 10 colonies in 

 Marin, San Francisco. San Mateo, and Monterey 

 Counties (Figure 2.2). One colony was previously 

 reported in southern California (Santa Barbara County) 

 at Prince Island, a record that represented the southern 

 breeding limit known for the species in California and 

 the world (Figure 2.2). Breeding has been confirmed 

 with observations of eggs or chicks at all colonies in 

 central California, the extirpated Prince Island colony 

 in southern California, and most colonies in northern 

 California (see Appendix B; Sowls et al. 1980, 

 unpublished data archive: Boekelheide et al. 1990: 

 Carter et al. 1992, unpublished data archive: 

 McChesney et al. 1994; H. R. Carter, unpublished data; 

 M. W. Parker, unpublished data: G. J. McChesney. 



