98 USGS/BRD/ITR-2000-0012 



flying jet aircraft caused extensive flushing of murre 

 colonies (Speich et al. 1987). 



Lessened Human Impacts and 

 Murre Colony Sizes (1969-1978) 



In 1969, the South Farallon Islands were included, 

 along with the North Farallon Islands, in the Farallon 

 National Wildlife Refuge, under the management of the 

 U.S. Fish and Wildlife Service (USFWS). Osborne ( 1 969) 

 reported only 200 breeding pairs in July-August 1 969, 

 although surveys probably were conducted too late in 

 the season. H. Cogswell (unpublished field notes) 

 estimated 2,000 murres on the island or flying around it 

 on 29 April 1 970; however, numbers "increased from 

 4,000 to 6,000 during April and May" (Baldridge et al. 

 1970a,b). Osborne and Reynolds (1971) reported 5,000 

 breeding pairs at the South Farallon Islands in 1970. In 

 1 97 1 , the Point Reyes Bird Observatory was contracted 

 by the USFWS to protect and monitor wildlife at the 

 Farallon Islands. In 1 974, all U.S. Coast Guard personnel 

 left the island. For the first time since the early nineteenth 

 century, human disturbance by island personnel was 

 reduced to minimal levels, including newly designated 

 off-limit areas on Southeast Farallon Island. West End 

 Island and the North Farallon Islands were designated 

 as National Wilderness Areas. 



Ainley and Lewis (1974) reported 20,500 breeding 

 birds at the South Farallon Islands in 1972 (based on 

 detailed on-island ground counts but without a k 

 correction factor). This 1972 estimate represented a large 

 increase in the size of the murre colony since 1959 but 

 the 1972 survey probably constituted a more careful 

 survey than any conducted previously, as well as 

 documenting breeding during an El Nino. Piatt et al. 

 (1991) noted that if the 1972 survey was adjusted with 

 a k correction factor and adjusted roughly for 

 comparability with more recent aerial survey estimates 

 (since 1979) and possible lower breeding effort during 

 1972-73 El Nino conditions (Lenarz et al. 1995), about 

 45,000 breeding birds could have laid eggs in 1972. H. 

 Cogswell (unpublished field notes), from a boat, reported 

 only 12,000 murres on Southeast Farallon Island (plus 

 several hundred on Seal Rock) on 30 April, suggesting 

 differences between counting techniques. On 22 April 

 1973, H. Cogswell (unpublished field notes) reported 

 several thousand at the island. No other detailed surveys 

 of the numbers of breeding murres were conducted at 

 the South Farallon Islands until 1979 when annual 

 ground and boat surveys began (Ainley and 

 Boekelheide 1990; Takekawa et al. 1990; Sydeman et 

 al. 1997). However, rough estimates of the numbers of 

 breeding pairs in 1 975-79 were reported by Point Reyes 



Bird Observatory to the USFWS, respectively, as 1 4,000, 

 14,000, 20,000, 25,000, and 30,000 (U.S. Fish and 

 Wildlife Service 1980). Ainley and Whitt (1974) 

 reported a 1972 estimate of 14,000 breeding pairs for 

 San Francisco County. This value included the South 

 Farallon Islands surveyed in 1972 (Ainley and Lewis 

 1974) and the North Farallon Islands surveyed in April 

 1 972. By subtracting 1 0,250 breeding pairs for the South 

 Farallon Islands (Ainley and Lewis 1974), a total of 

 between 2,246 and 3,750 breeding pairs can be 

 calculated for the North Farallon Islands in 1972, 

 depending on whether a k correction factor was applied. 

 No other surveys were conducted at the North Farallon 

 Islands until 1980 (Briggs et al. 1983). 



Other Central California Breeding Colonies 



Point Reyes Complex 



Murres were noted breeding on Point Reyes on 23 

 June 1897, when three eggs were collected by Italian 

 fishermen for O. Emerson (WFVZ Nos. 112,841, 

 1 14,859-1 14,860). Emerson noted on the specimen card 

 that the colony was "regularly visited by eggers until 

 prohibited by law." On 20 April 1913, E. B. Coues and 

 C. E. Ingalls collected at least nine eggs (set numbers 

 5,369-5,377; USNM Nos. 34,233-34,241). On 12 June 

 1932, four eggs were collected by J.S. Rowley at Point 

 Reyes (WFVZ Nos. 26,1 1 1-26,1 14). However, his set 

 numbers were: 2, 8, 10, 11, suggesting that 1 1 or more 

 eggs were collected. On 29 April 1934, 1,500 murres 

 were noted (L. O. Williams, unpublished field notes) 

 and "many young in downy plumage" were noted by 

 McCabe on 5 August 1934 (Allen 1934). One thousand 

 murres were reported breeding at Point Reyes lighthouse 

 rocks on 6 June 1938 (Anonymous 1938). 



Murres with eggs were noted on 16 May 1939, and 

 2,200 murres (small downy young present) were counted 

 on 23 June 1 939 on the murre rock at the Point Reyes 

 lighthouse (L. O. Williams, unpublished field notes). 

 Williams (1942) noted that murre numbers had "kept 

 up" at Point Reyes during the years from 1933 to 1940. 

 Grinnell and Miller (1944) indicated that breeding had 

 been reported by J. and J. W. Mailliard but did not 

 present other data. One thousand murres were reported 

 by Rigby on 13 July 1947 (L. O. Williams, unpublished 

 field notes). Storer (1952) noted 5,000 murres and H. 

 Cogswell (unpublished field notes) noted 3,000 murres 

 on the rock below the lighthouse at Point Reyes on 13 

 February 1 949. It is not clear if Storer counted murres at 

 other locations (in addition to the rock below the 

 lighthouse) from other vantage points along the 

 headlands. However, many murres both below the 



