BIOLOGY AND CONSERVATION OF THE COMMON MURRE 97 



Murre Colony Sizes (191 1-1950) 



From 1911 to 1950, murres were not recorded 

 breeding at the South Farallon Islands in large numbers. 

 Only a few hundred to a few thousand murres probably 

 bred there during much of this period. By 1911, fewer 

 than 20.000 murres were estimated at the South Farallon 

 Islands (Dawson 1911). Egg collectors frequently 

 obtained eggs from the South Farallon Islands from 1 859 

 to 1913, based on hundreds of egg specimens collected 

 during this period in collections at: WFVZ; Santa 

 Barbara Museum of Natural History (SBNHM), Santa 

 Barbara, California; University of California Museum 

 of Vertebrate Zoology (BMVZ), Berkeley, California; 

 National Museum of Natural History (USNM), 

 Smithsonian Institution, Washington, D.C.; and Harvard 

 University Museum of Comparative Zoology (MCZ), 

 Cambridge, Massachusetts. I did not present details for 

 these Farallon-collected eggs in this appendix because 

 the history of egging and other visits by ornithologists 

 are well told with other information above. No eggs in 

 these collections were obtained after this period. On 20 

 August 1922, murres were considered to be less 

 numerous than in 1917 although some birds may have 

 fledged by this date (Allen 1922; Kibbe 1922). However, 

 murres may have regularly bred that late in the year 

 because of effects from egging when breeding often 

 extended into September (Bryant 1888), although 

 1859-1913 egg specimen dates ranged between 1 May 

 1 890 (USNM B3423 1 ) and 28 July 1 886 (WFVZ 4601 6), 

 with most collected in June. In June 1923, Chancy 

 (1924) reported only tens of murres breeding in three 

 small groups in protected crevices. On 24 August 1930, 

 only five murres were found at the island, which may 

 have reflected near extermination and earlier breeding 

 by small numbers since some birds were observed at sea 

 with chicks (Anonymous 1930; Lastreto 1930). However, 

 the lighthouse keeper indicated that murres had been 

 depopulated by about 99% (since Knuder had come to 

 the Farallones in 1915 [White 1995]); this decline was 

 related to past egging practices and oil pollution but 

 remaining smaller numbers of murres were falling prey 

 to western gulls (Larus occidentalism Allen 1930; Knuder 

 1930; Lastreto 1930; Brooks 1937). In August 1933, 

 Smith (1934) observed only three young in protected 

 crevices but noted that the main colony probably had 

 finished breeding earlier. Smith also noted that strict 

 protection of breeding areas was occurring and no one 

 was permitted to travel to West End Island from 1 5 April 

 to 15 August. 



Murre Colony Sizes (1950- 1968) 



On 22 May 1955, about 2,000 murres were reported 

 within 3.2 km (2 miles) of the islands but it was unclear 



how many were on shore. On 30 April and 22 May 1 955, 

 thousands were reported on the island and on the water 

 around the island (H. Cogswell, unpublished field notes; 

 Cogswell 1955; Cogswell and Pray 1955a). On 28 April 

 1956, Cogswell noted about 1,000 murres at and around 

 the island, including 600 on the island. On 27 May 

 1 956, he reported 300 murres at the island, and hundreds 

 also were reported on 3 June 1956 at the island 

 (Cogswell and Stallcup 1956; H. Cogswell, unpublished 

 field notes). On 10-17 June 1958, Bowman (1961) 

 conducted an on-island survey of the South Farallon 

 Islands and determined about 2,000 birds attending 

 eggs. He mapped breeding areas and noted small groups 

 of 5-20 birds breeding in caves and on ledges at several 

 points. The largest groups were on the westernmost parts 

 of West End Island (Great Arch, Phil's Hill, and Indian 

 Head) and on Sugarloaf and Aulon Islet. Smaller 

 numbers bred at Southeast Farallon Island (Shubrick 

 Point, Great Murre Cave. Shubrick Cove, and Fertilizer 

 Flat), Saddle Rock, the Islets (Arch Rock. Finger Rock, 

 and Sealion islets), and other parts of West End Island 

 (Maintop, Pelican Bowl, and West End Cove). Thoreson 

 (1959) reported a direct count of 6,718 murres and a 

 range of 6,000-7,000 birds at the South Farallon Islands 

 in June- August 1959. Most birds were counted at the 

 Islets (2,000) and West End Island (3.500). Bowman's 

 and Thoreson's estimates seem to be the first well 

 documented numbers of breeding birds on the South 

 Farallon Islands but also may reflect lower breeding 

 effort during El Nino conditions in 1957-59 (Lenarz et 

 al. 1995). On 3 April 1960. murres and pigeon guillemots 

 (Cepphus columba) were reported as abundant at the 

 island (Albertson 1960). D. Bleitz (unpublished field 

 notes) noted concentrated small colonies on high steep- 

 walled pinnacles on 4 August 1961. On 19 April 1962, 

 thousands were reported on or near the island (H. 

 Cogswell, unpublished field notes). On 31 March 1963, 

 thousands of murres and other species were noted at the 

 island (Paxton 1963). On 31 May 1964. murres and 

 other species were "ubiquitous" at the main island 

 (Paxton 1964). Pinney (1965) mapped locations where 

 murres bred on Southeast Farallon Island in 1961-64, 

 including Shubrick Point, Great Murre Cave, Shubrick 

 Cove, Fertilizer Flat. Tower Point, and Elephant Seal 

 Blind Point. On 23 April 1966, hundreds of murres flew 

 from the rocks (Stallcup and Chandik 1966) and H. 

 Cogswell (unpublished field notes. American Birds 

 Files; Chase and Chandik 1966) reported several 

 thousand on the island and noted that the "population 

 felt to be decidedly larger than 8-10 years previously." 

 On 14 June 1967, a rough estimate of 500 murres at 

 Shubrick Point was made from land (H. Cogswell, 

 unpublished field notes). During summer 1968, low- 



