90 USGS/BRD/ITR-2000-0012 



traveling at 1 85 km/h parallel to shore (i.e., 0.4 km from 

 shore at altitudes of 60-300 m). Photographs were taken 

 of all aggregations of more than 1 birds and later were 

 inspected to verify visual estimates. Nonstandardized 

 techniques were used because of permit restrictions near 

 murre and other seabird colonies and probably resulted 

 in less accurate whole-colony counts of murres (K. T. 

 Briggs and R. G. Ford, personal communication). The 

 uncorrected count was 262,364 birds (Briggs et al. 1992). 

 Data obtained by Ecological Consulting Incorporated 

 were considered inaccurate and were not used for trend 

 analyses in Chapter 2 because (1) nonstandardized 

 survey techniques were used; (2) the survey did not 

 include 29 (42%; n = 69) active murre colonies in 

 Oregon in 1989, especially some large colonies 

 exceeding 10,000 birds; (3) some counts were reported 

 for rocks where murre colonies were not present; and (4) 

 counts for many colonies were lumped together as a 

 single count. Large discrepancies exist where 1989 

 standardized counts by the USFWS (7 and 9 June) can 

 be compared with those of Briggs et al. ( 1 992). At eight 

 sites compared, the Briggs et al. survey reported greater 

 numbers at three colonies (range, 5-45%) and 

 significantly lower numbers at the other five colonies 

 (range, 49-98%) than the USFWS survey. 



Since 1988, single annual surveys of all major murre 

 colonies in Oregon have been conducted (except 1995; 

 Table A-3) using standardized techniques. Surveys were 

 flown in early June to coincide with late incubation 

 and hatching (after Takekawa et al. 1990). Surveys were 

 conducted using a Hughes 500 (models D & E) 

 helicopter at altitudes of 260-330 m with both right- 

 side doors removed. The five-bladed propeller 

 configuration reduces noise and lessens possible 

 disturbance. On rare occasions, small numbers of murres 

 have flushed from rocks. These birds are typically on 

 the edges of the colony and probably involve 

 prospecting or roosting birds, but the numbers are 

 recorded and included in the colony count. Colony 

 photographs were taken by two photographers using 

 35-mm cameras with 100-300- or 300-mm lenses for 

 close-up photographs (front-seat photographers) using 

 ASA 400 color slide film and shutter speeds of 1/500 or 

 1/1000 per sec, and 55- or 70-210-mm lenses for colony 

 overviews (back-seat photographer). Overlapping 

 colony slides were projected onto large sheets of paper, 

 simultaneously using 3-4 projectors and individual 

 birds were counted. A general k correction factor of 1 .67 

 (based on California data) was applied to all count data 

 to estimate the number of breeding adults at colonies in 

 Oregon. No study has calculated a k specific to Oregon 

 colonies. 



The first trial of this photographic survey method 

 was conducted along the southern Oregon coast in June 

 1986. The survey was expanded to the entire Oregon 

 coast in 1987, though not all colonies were counted. 

 From 1988 to 1995, all major murre colonies in Oregon 

 were photographed annually. 



In 1995, three replicate aerial photographic surveys 

 were conducted at a subset of Oregon colonies. These 

 surveys were conducted at 15 north coast study sites 

 both 2 weeks before and 2 weeks after the standard June 

 survey (i.e., 23 May, 7 June, and 21 June) to examine 

 the validity of using a single survey as a general measure 

 of peak numbers of murres at colonies. The results 

 showed considerable variation in the number of birds 

 present at some specific colony sites. However, overall 

 numbers of birds recorded in each survey were similar. 

 On 23 May and 21 June, 1 .3% more and 2.5% less birds 

 were recorded, respectively, compared with the standard 

 survey on 7 June. The mean total of birds recorded for 

 the three surveys was only 0.4% less than the total for 

 the standard early June survey. The results indicated 

 that, at least in 1995, the single standard survey in early 

 June was sufficient and accurate enough for population 

 monitoring and trend analyses. 



Washington 



Murre colonies in Washington were aerially 

 surveyed each year in late June or early July from 1 979 

 to 1995 (Table A-3). This later timing of surveys 

 reflected a later timing of breeding (Manuwal and Carter 

 2001) and greater stability of numbers of murres on 

 colonies after May (Speich et al. 1987; Parrish 1995). 

 For the 1979-83 period, a single, annual survey was 

 flown with a Cessna 172 or 182 at an altitude of 170- 

 230 m and murres were counted later from aerial 

 photographic slides. Since 1983, all surveys were 

 conducted with a Hughes 500 D helicopter at an 

 elevation of 70-250 m (with the passenger door 

 removed). Murres were counted with a hand-held tally 

 counter and binoculars, except in 1987, 1994, and 1995 

 when birds were photographed and later counted from 

 slides. Direct counts were considered acceptable because 

 of the small numbers of birds attending most colonies. 

 Census data were obtained during single helicopter 

 flights through 1993. Two flights were conducted in 

 1994 and four replicate flights in 1995. During fixed- 

 wing surveys, it was possible to count only the major 

 murre colonies, whereas the helicopter allowed surveys 

 of all sites, except the Tatoosh complex. This complex 

 has been surveyed by the USFWS only since 1994. 

 Surveys were flown between 0930 and 1400 h (PDT) 

 during late June or early July. During multiple survey 

 years, surveys were conducted between mid-June and 



