BIOLOGY AND CONSERVATION OF THE COMMON MURRE 87 



Appendix A 



Techniques for aerial and other photographic surveys of common murre (Uria aalge califomica) colonies 

 in California, Oregon, Washington, and British Columbia 



(prepared by H. R. Carter, J. E. Takekawa, R. W. Lowe, and U. W. Wilson) 



In this appendix, we summarize various aspects of 

 techniques for aerial and other photographic surveys of 

 common murres (Uria aalge califomica) conducted in 

 California. Oregon. Washington, and British Columbia 

 from 1979 to 1995. 



California 



Aerial surveys in 1969-70 apparently involved 

 mainly visual estimates with some photographs taken 

 for back-up documentation (Osborne and Reynolds 

 1971;Osborne 1972). In 1979-80. U.S. Fish and Wildlife 

 Service (USFWS) personnel conducted aerial surveys 

 of colonies using high- wing Cessna 1 82 or 210 aircraft, 

 or U.S. Coast Guard helicopters (Figure A-l ; Sowls et 

 al. 1980). Color photographs were taken at altitudes of 

 150-250 m. using 35-mm cameras with 70-210- or 

 300-mm lenses, mainly near midday. In 1 980-82, staff 

 from the University of California at Santa Cruz 

 conducted aerial surveys from a high- wing, twin engine 

 Hunting Pembroke, flying a coastal survey track about 

 100 m from shore (Briggs et al. 1983. 1987). Photographs 

 were taken mostly at altitudes of 100-200 m along most 

 of the coast (except at the Farallon Islands and other 

 sensitive areas where altitude was increased to 300- 

 400 m), using 35-mm cameras with 80-200- or 300-mm 

 lenses. These techniques were generally comparable, 

 although few passes were made at each colony, such 

 that colony coverage and photograph quality often 

 varied between colonies and surveys. In higher-quality 

 photographs, counts of individual birds were made and. 

 in lower-quality photographs, blocks of 10. 50. or 100 

 birds were counted. Photographs were occasionally 

 supplemented with visual estimates. Small numbers of 

 murres were flushed from colonies by low-flying aircraft. 



Aerial photographic surveys of murre colonies were 

 improved and better standardized from 1985 to 1995 

 by the USFWS, National Biological Service, U.S. 

 Geological Survey, and Humboldt State University 

 (Takekawa et al. 1990; Carter et al. 1992, 1995, 19%. 

 2000: Sydeman et al. 1997: McChesney et al. 1998. 

 1999: see Tables A-l and A-2). In general, counts were 

 considered to be comparable at most colonies from 1 979 

 to 1995. However, notable exceptions were Castle Rock 

 in 1979-82 and Point Reyes in 1979-81. Since 1985. 

 all central California colonies have been surveyed using 



either a high-wing, twin-engine Partanavia (or a Cessna 

 337 aircraft). At the South Farallon Islands, colonies 

 were surveyed from about 183 to 274 m (600 to 900 

 feet) and others from about 122 to 213 m (400 to 700 

 feet). Northern California colonies were surveyed at 

 altitudes of 122 to 213 m (400 to 700 feet) using a 

 single-engine Cessna 150 or 182 (1985-90) or a 

 high-wing, twin-engine Partanavia (1993-95). In most 

 years, colonies were surveyed once in late May or early 

 June (i.e., near the end of egg laying and before colony 

 departure). During this period, murre numbers are high 

 and least variable (Takekawa et al. 1990). On rare 

 occasions, small numbers of murres were flushed from 

 colonies and surveys were continued at higher altitudes. 

 At the South Farallon Islands, surveys were conducted 



Figure A-1. Aerial photography was conducted with hand-held cameras 

 from helicopters in Oregon and Washington, and from fixed-wing 

 aircraft in California. In this photo, R. W. Lowe is taking photographs 

 from a helicopter at Three Arch Rocks, Oregon (Photo by D. S. Pitkin). 



