88 USGS/BRD/ITR-2000-0012 



Table A-1. Summary of aerial photographic surveys of common murre colonies in central California, 1 979-1995. 3 



Table A-2. Summary of aerial photographic surveys of common murre colonies in northern California, 1 979-1 995. a 



a See Appendixes C and D 

 b Unpublished data 



at higher altitudes and farther from shore to prevent 

 flushing. 



Entire colonies were photographed by two (one 

 front-seat and one back-seat) photographers between 

 1000 and 1400 h (PDT), using 35-mm cameras with 

 300-mm lens. Each part of a colony was passed over 

 several times to ensure photograph quality and 

 overlapping coverage of all breeding areas. Close-up 

 slides of each part of the colony from either 

 photographer were pieced together using separate 



overview photographs taken only by the front-seat 

 photographer using a 50-mm lens. Slides were then 

 projected on white paper and each murre was counted 

 (Figure A-2). 



After obtaining direct whole-colony counts of 

 murres from aerial photographs, a k correction factor 

 can be used to estimate the total number of breeding 

 birds using the colony in the survey year. Based on 

 counts of murres and egg-laying sites in a plot on Upper 

 Shubrick Point on the South Farallon Islands, California, 



