Distribution and Abundance of Marbled Murrelets and Common Murres on

the Outer Coast of Washington — Summer 1997 through Winter 1998-1999

15 May 1999

Christopher W. Thompson

Washington Department of Fish and Wildlife
For the summers of 1997 and 1998, and winters of 1997-1998 and 1998-1999, the Tenyo Maru

Trusteeís Council (TMTC), U.S. Fish and Wildlife Service, and Washington Department of

Natural Resources Funded Washington Department of Fish and Wildlife (WDFW) to complete a

variety of specific tasks related to three general objectives: (1) further document the summer and

winter at-sea distribution and abundance of Common Murres and Marbled Murrelets along the

outer coast of Washington and Strait of Juan de Fuca, (2) conduct surveys of potential Common

Murre breeding colonies along the central coast of Washington, and (3) document post-breeding

dispersal of of Common Murres from the breeding colonies in Oregon northward along the outer

coast of Washington and eastward along the Strait of Juan de Fuca. The specific tasks associated

with each of these objectives were completed; analyses of the data collected for each of these

tasks are presented and discussed below.

Objective 1: At-sea distribution and abundance of Common Murres and

Marbled Murrelets.

Specific tasks funded: 

(1) Empirically quantify sampling efficiencies of zig-zag vs. parallel transects

(2) Continue to document long-term seasonal and annual variation in abundance and distribution

(3) Evaluate line vs. strip transect methodology

Task 1

There are two related components to this task: (a) comparison of accuracy and relative statistical

power of zig-zag vs. parallel transects for both Common Murres (hereafter murres) and Marbled

Murrelets (hereafter murrelets), and (b) determination of the average number of transects

necessary to detect a change in density of murres or murrelets of a specified magnitude over a

specified time interval (e.g., between seasons, years).

In previous summers and winters, we conducted replicate transects at various distances parallel

to shore along the outer coast of Washington and Strait of Juan de Fuca as well as zig-zag

transects that covered the range of distances from shore that were covered by parallel transects.

To increase our sample size as well as gain additional data on seasonal and annual variation in

murrelet density, we collected additional sets of parallel and zig-zag transects in the summers and

winters of 1997 and 1998. Our overall survey effort is summarized in Tables 1- 5 below. The

data from our parallel and zig-zag transects is summarized in Figures 1-5 and Tables 6 - 8 below.
Table 1. Date, geographic location, and length (kilometers) of transects conducted in the

winter of 1996-1997 and associated densities of Marbled Murrelets along the outer coast

of Washington and Strait of Juan de Fuca. 

Survey Date Transect Location, Description, and Time

Transect 

Length

(km)

Number of

Marbled

Murrelets

Observed

Density

of

Marbled

Murrelets

per km2

04 February Port Angeles to Hoko River, 200 M, AM 83.58 24 1.44

04 February Slip Point to Observatory Point, 400 M, PM 61.84 5 0.40

05 February Port Angeles to Slip Point, 400 M, AM 71.77 10 0.70

05 February Slip Point to Port Angeles, 200 M, PM 68.06 8 0.59

06 February Port Angeles to Slip Point, 800 M, AM 71.56 11 0.77

06 February Slip Point to Port Angeles, 1200 M, PM 70.69 34 2.40

07 February Port Angeles to Slip Point, 1200 M, AM 71.27 12 0.84

07 February Slip Point to Port Angeles, 400 M, PM 71.66 7 0.49

13 February Neah Bay to Slip Point, 200 M, AM 31.40 44 7.01

13 February Slip Point to Neah Bay, 400 M, AM 30.10 9 1.50

13 February Neah Bay to Slip Point (inc.), 200 M, PM 4.88 5 5.12

20 February Slip Point to Neah Bay, 800 M, AM 29.69 1 0.17

20 February Neah Bay to Slip Point, 1200 M, PM 27.36 2 0.37

04 March Grayís Harbor, AM/PM 80.70 2 0.12

05 March Grayís Harbor, AM/PM 36.62 8 1.09

06 March Willapa Bay, AM 26.34 0 0

11 March Ocean Shores to Point Grenville, 1200 M, AM 16.96 0 0

11 March Point Grenville to Ocean Shores, 200 M, AM 22.43 7 1.56

12 March Grayís Harbor to Willapa Bay, 1200 M, AM 22.02 1 0.23

20 March Willapa Bay, high tide, PM 22.93 0 0

20 March Willapa Bay, low tide, PM 36.14 2 0.28

21 March Willapa Bay, AM/PM 104.64 17 0.81

25 March Grayís Harbor to Willapa Bay, 200 M, PM 16.43 1 0.30

25 March Willapa Bay to Grayís Harbor, 1200 M, PM 15.96 0 0

26 March Grayís Harbor to Willapa Bay, 200 M, AM 16.02 2 0.62

26 March Willapa Bay to Grayís Harbor, 1200 M, AM 20.78 8 1.92 Total Kilometers Surveyed: 1131.83
Table 2. Date, geographic location, and length (kilometers) of transects conducted in the summer of 1997 and

associated densities of Common Murres and Marbled Murrelets along the outer coast of Washington andStrait of Juan de Fuca. 

Number of Density of Number of Density of

General Distance Time of Common Common Marbled Marbled

Survey Geographic from Day (AM Transect Murres Murres per Murrelets Murrelets perDate Location Transect Location shore or PM) L e n g t h

(km)

Observed Square Km Observed Square Km

11 June North Coast Fuca Pillar to Point of Arches 400 M AM 10.42 39 18.71 2 0.53 11 June North Coast Fuca Pillar to Point of Arches Zig-Zag AM 17.28 140 40.51 5 0.62 12 June North Coast Fuca Pillar to Point of Arches 1000 M AM 16.06 81 25.22 6 1.19 12 June North Coast Fuca Pillar to Point of Arches 400 M AM 16.98 53 15.61 8 2.56 12 June North Coast Fuca Pillar to Point of Arches 700 M AM 12.52 107 42.73 3 0.35 12 June North Coast Fuca Pillar to Point of Arches Zig-Zag AM 15.74 37 11.75 7 2.98 12 June North Coast Fuca Pillar to Point of Arches 1000 M PM 13.91 38 13.66 0 0.00 12 June North Coast Fuca Pillar to Point of Arches 400 M PM 16.73 73 21.82 10 2.29 12 June North Coast Fuca Pillar to Point of Arches 700 M PM 12.27 78 31.78 3 0.47 12 June North Coast Fuca Pillar to Point of Arches Zig-Zag PM 16.41 119 36.26 0 0.00 19 June South Coast Columbia R. to Gray's Harbor Nearshore AM 82.9 828 49.94 0 0.00 20 June South Coast Columbia R. to Gray's Harbor Offshore PM 73.03 569 38.96 2 0.26 20 June South Coast Columbia R. to Gray's Harbor Nearshore AM 75.82 275 18.14 2 0.55 20 June Gray's Harbor Gray's Harbor (mouth) PM 7.81 115 73.62 0 0.00 24 June North Coast Fuca Pillar to Point of Arches 1000 M AM 14.57 138 47.36 0 0.00 24 June North Coast Fuca Pillar to Point of Arches 400 M AM 16.53 102 30.85 6 0.97 24 June North Coast Fuca Pillar to Point of Arches 700 M AM 12.46 44 17.66 2 0.57 24 June North Coast Fuca Pillar to Point of Arches Zig-Zag AM 17.41 113 32.45 2 0.31 24 June North Coast Fuca Pillar to Point of Arches 1000 M PM 16.1 109 33.85 0 0.00 24 June North Coast Fuca Pillar to Point of Arches 400 M PM 17.08 72 21.08 17 4.03 24 June North Coast Fuca Pillar to Point of Arches 700 M PM 12.81 129 50.35 3 0.30 24 June North Coast Fuca Pillar to Point of Arches Zig-Zag PM 19.21 144 37.48 2 0.27 25 June North Coast Fuca Pillar to Point of Arches 1000 M PM 14.74 244 82.77 0 0.00 25 June North Coast Fuca Pillar to Point of Arches 400 M PM 16.31 111 34.03 1 0.15 25 June North Coast Fuca Pillar to Point of Arches 700 M AM 12.64 29 11.47 1 0.44 25 June North Coast Fuca Pillar to Point of Arches Zig-Zag AM 17.93 99 27.61 2 0.36 02 July Columbia River Columbia River (mouth) PM 67.88 52 3.83 0 0.00 02 July South Coast Willapa Bay to Columbia R. Nearshore AM 70.4 370 26.28 0 0.00 02 July South Coast Willapa Bay to Columbia R. Offshore PM 51.81 116 11.19 4 1.79 09 July North Coast Fuca Pillar to Point of Arches 1000 M AM 14.07 144 51.17 12 1.17 09 July North Coast Fuca Pillar to Point of Arches 400 M AM 18.08 240 66.37 6 0.45 09 July North Coast Fuca Pillar to Point of Arches 700 M AM 9.42 65 34.50 11 1.59 09 July North Coast Fuca Pillar to Point of Arches Zig-Zag AM 16.04 277 86.35 15 0.87 09 July North Coast Fuca Pillar to Point of Arches 1000 M PM 14.22 191 67.16 3 0.22 
09 July North Coast Fuca Pillar to Point of Arches 400 M PM 16.26 256 78.72 27 1.71 

09 July North Coast Fuca Pillar to Point of Arches 700 M PM 10.59 130 61.38 5 0.41 09 July North Coast Fuca Pillar to Point of Arches Zig-Zag PM 17 224 65.88 14 1.06 10 July North Coast Fuca Pillar to Point of Arches 1000 M AM 14.04 171 60.90 6 0.49 10 July North Coast Fuca Pillar to Point of Arches 400 M AM 11.44 160 69.93 4 0.29 10 July North Coast Fuca Pillar to Point of Arches 700 M AM 13.03 103 39.52 3 0.38 10 July North Coast Fuca Pillar to Point of Arches Zig-Zag AM 16.82 160 47.56 17 1.79 10 July North Coast Fuca Pillar to Point of Arches 1000 M PM 13.97 93 33.29 12 1.80 10 July North Coast Fuca Pillar to Point of Arches 400 M PM 15.97 92 28.80 27 4.69 15 July North Coast Ocean Shores to Pt. Grenville Nearshore AM 43.24 238 27.52 34 6.18 15 July North Coast Pt. Grenville Grid AM 46.58 730 78.36 30 1.91 15 July North Coast Ocean Shores to Pt. Grenville Offshore PM 42.72 150 17.56 7 1.99 16 July South Coast Columbia River to Willapa Bay Offshore AM 76.34 919 60.19 12 1.00 16 July Gray's Harbor Gray's Harbor (mouth) PM 6.49 24 18.49 0 0.00 17 July North Coast Pt. Grenville Grid AM 42.86 318 37.10 33 4.45 17 July South Coast Columbia River to Willapa Bay Nearshore PM 75.48 1333 88.30 8 0.45 22 July Strait Seal Rock to Kydaka Point 200 M AM 14.48 1 0.35 30 434.40 22 July Strait Seal Rock to Kydaka Point 500 M AM 14.14 27 9.55 9 4.71 22 July Strait Seal Rock to Kydaka Point 800 M AM 14.39 31 10.77 3 1.39 22 July Strait Seal Rock to Kydaka Point Zig-Zag PM 16.72 52 15.55 12 3.86 22 July Strait Seal Rock to Kydaka Point 200 M PM 14.4 11 3.82 8 10.47 22 July Strait Seal Rock to Kydaka Point 500 M PM 14.74 9 3.05 1 1.64 22 July Strait Seal Rock to Kydaka Point 800 M PM 14.28 34 11.90 1 0.42 22 July Strait Seal Rock to Kydaka Point Zig-Zag PM 17.3 52 15.03 0 0.00 23 July Strait Seal Rock to Kydaka Point 200 M (inc) AM 6.1 30 24.59 9 1.83 23 July Strait Seal Rock to Kydaka Point 200 M PM 14.68 324 110.35 9 0.41 23 July Strait Seal Rock to Kydaka Point 500 M (inc) PM 7.33 8 5.46 0 0.00 23 July Strait Seal Rock to Kydaka Point 800 M AM 14.1 256 90.78 2 0.11 23 July Strait Seal Rock to Kydaka Point Zig-Zag PM 21.03 131 31.15 2 0.32 23 July Strait Seal Rock to Kydaka Point 500 M PM 14.1 69 24.47 1 0.20 24 July Strait Seal Rock to Kydaka Point 200 M AM 15.04 41 13.63 19 6.97 24 July Strait Seal Rock to Kydaka Point 500 M AM 14.33 51 17.79 4 1.12 24 July Strait Seal Rock to Kydaka Point 800 M AM 13.93 42 15.08 0 0.00 24 July Strait Seal Rock to Kydaka Point Zig-Zag AM 19.68 208 52.85 16 1.51 24 July Strait Seal Rock to Kydaka Point 200 M PM 15.03 14 4.66 23 24.69 24 July Strait Seal Rock to Kydaka Point 500 M AM 14.28 159 55.67 5 0.45 24 July Strait Seal Rock to Kydaka Point 800 M PM 14 29 10.36 0 0.00 24 July Strait Seal Rock to Kydaka Point Zig-Zag PM 20.78 183 44.03 8 0.91 25 July Strait Seal Rock to Kydaka Point 500 M (inc) AM 10.32 41 19.86 3 0.76 25 July Strait Seal Rock to Kydaka Point 800 M AM 14.05 115 40.93 2 0.24 30 July South Coast Columbia River to Willapa Bay Nearshore AM 80.88 1451 89.70 2 0.11 30 July South Coast Columbia River to Willapa Bay Offshore PM 81.09 1147 70.72 1 0.07 
31 July South Coast Columbia River to Willapa Bay Offshore AM 82.91 757 45.65 0 0.00 

31 July South Coast Columbia River to Willapa Bay Nearshore PM 77.06 437 28.35 1 0.18 05 Aug Strait Port Angeles to Neah Bay Nearshore AM 102.41 32 1.56 293 937.69 06 Aug North Coast Lapush to Neah Bay offshore PM 80.25 448 27.91 0 0.00 06 Aug North Coast Neah Bay to Lapush nearshore AM 80.11 392 24.47 20 4.09 07 Aug Strait Neah Bay to Port Angeles Offshore AM 97.95 372 18.99 35 9.22 12 Aug South Coast Columbia River to Willapa Bay Offshore PM 77.03 511 33.17 4 0.60 12 Aug Gray's Harbor Grays Harbor (mouth) PM 4.26 1 1.17 0 0.00 12 Aug South Coast Columbia River to Willapa Bay Nearshore AM 76.79 563 36.66 0 0.00 13 Aug North Coast Umatilla to Lapush Offshore PM 133.56 89 3.33 6 9.00 13 Aug North Coast Lapush to Willapa Bay Nearshore AM 161.06 406 12.60 95 37.69 14 Aug Gray's Harbor Gray's Harbor (mouth) PM 8.15 20 12.27 0 0.00 14 Aug North Coast Lapush to Willapa Bay Offshore AM 124.66 754 30.24 44 7.27 19 Aug Strait Port Angeles to Neah Bay Offshore AM 97.08 315 16.22 2 0.62 19 Aug Strait Seal Rock to Kydaka Point 200 M PM 14.63 40 13.67 13 4.75 19 Aug Strait Seal Rock to Kydaka Point 500 M PM 15.52 17 5.48 1 0.91 19 Aug Strait Seal Rock to Kydaka Point 800 M PM 14.67 40 13.63 1 0.37 19 Aug Strait Seal Rock to Kydaka Point Zig-Zag PM 18.98 58 15.28 2 0.65 20 Aug Strait Seal Rock to Kydaka Point 500 M AM 14.99 31 10.34 1 0.48 20 Aug Strait Seal Rock to Kydaka Point Zig-Zag AM 20.69 67 16.19 4 1.24 20 Aug Strait Neah Bay to Port Angeles Nearshore PM 102.9 210 10.20 306 149.94 25 Aug Strait Seal Rock to Kydaka Point 200 M AM 14.99 55 18.35 6 1.64 25 Aug Strait Seal Rock to Kydaka Point 800 M AM 13.73 25 9.10 0 0.00 25 Aug Strait Seal Rock to Kydaka Point 200 M PM 14.87 26 8.74 3 1.72 25 Aug Strait Seal Rock to Kydaka Point 500 M PM 14.17 10 3.53 0 0.00 25 Aug Strait Seal Rock to Kydaka Point 800 M PM 13.89 19 6.84 0 0.00 25 Aug Strait Seal Rock to Kydaka Point Zig-Zag AM 20.6 25 6.07 3 2.47 28 Aug North Coast Line 11 (first part) 28.61 15 2.62 0 0.00 

29 Aug North Coast Line 1 (completion) 50.42 28 2.78 0 0.00 30 Aug North Coast Line 7 4.87 0 0.00 0 0.00 30 Aug North Coast Line 8 6.12 1 0.82 0 0.00 30 Aug North Coast Line 9 8.33 4 2.40 0 0.00 30 Aug North Coast Line 10 6.49 10 7.70 0 0.00 30 Aug North Coast Line 11 10.16 11 5.41 0 0.00 30 Aug North Coast Line 12 7.35 1 0.68 0 0.00 31 Aug South Coast Line 13 44.08 194 22.01 0 0.00 1 Sept South Coast Line 14 47.61 41 4.31 0 0.00 1 Sept South Coast Line 15 11.07 0 0.00 0 0.00 2 Sept South Coast Line 16 36.02 12 1.67 0 0.00 2 Sept South Coast Line 17 4.89 0 0.00 0 0.00 2 Sept South Coast Line 18 23.07 20 4.33 0 0.00 3 Sept South Coast Line 19 18.4 18 4.89 0 0.00 
3 Sept South Coast Line 20 6.51 0 0.00 0 0.00 

3 Sept South Coast Line 21 17.89 19 5.31 0 0.00 3 Sept South Coast Line 22 6.19 11 8.89 0 0.00 3 Sept South Coast Line 23 22.51 18 4.00 0 0.00 4 Sept South Coast Line 24 26.81 34 6.34 0 0.00 4 Sept South Coast Line 25 5.99 1 0.83 0 0.00 4 Sept South Coast Line 26 22.54 29 6.43 0 0.00 5 Sept South Coast Line 27 31.59 26 4.12 0 0.00 5 Sept South Coast Line 28 20.29 66 16.26 0 0.00 6 Sept South Coast Line 29 13.73 16 5.83 0 0.00 6 Sept South Coast Line 30 42.88 64 7.46 0 0.00 7 Sept South Coast Line 31 19.53 80 20.48 0 0.00 7 Sept South Coast Line 32 5.6 2 1.79 0 0.00 7 Sept South Coast Line 33 20.43 44 10.77 0 0.00 8 Sept South Coast Line 34 21 14 3.33 0 0.00 8 Sept South Coast Line 35 5.62 0 0.00 0 0.00 8 Sept South Coast Line 36 21.96 17 3.87 0 0.00 9 Sept South Coast Line 37 23.41 9 1.92 0 0.00 9 Sept South Coast Line 38 20.73 6 1.45 0 0.00 10 Sept South Coast Line 39 81.36 288 17.70 0 0.00 12 Sept South Coast Line 40 5.94 0 0.00 0 0.00 12 Sept South Coast Line 41 25.08 20 3.99 0 0.00 12 Sept South Coast Line 42 5.71 1 0.88 0 0.00 12 Sept South Coast Line 43 24.4 17 3.48 0 0.00 13 Sept South Coast Line 44 2.33 5 10.73 0 0.00 13 Sept South Coast Line 45 15.97 2 0.63 0 0.00 13 Sept South Coast Line 46 21.78 15 3.44 1 1.45 13 Sept South Coast Line 47 23.68 22 4.65 0 0.00 

 Total Kilometers Surveyed: 4178.48

1 These line numbers refer to transects approximately parallel and perpendicular to shore conducted by theU.S. Geological Survey as part of a study of nearshore bathymetry along the outer coast of northern Oregonand southern Washington.
Table 3. Date, geographic location, and length (kilometers) of transects conducted in the winter of

1997-1998 and associated densities of Common Murres and Marbled Murrelets along the outer coast of

Washington and Strait of Juan de Fuca. 

Common Marbled

Number of Murre Number of Murrelet

Survey Transect Common Density Marbled Density

Date Location Length (km) Murres per sq. km Murrelets per sq. km

22 January 1998 Seal/Sail Rock to Kydaka Point, 200 M, AM 15.52 1 0.32 10 3.22 

" Seal/Sail Rock to Kydaka Point, 500 M, AM 15.11 10 3.31 10 3.31 

27 January 1998 Seal/Sail Rock to Kydaka Point, 200 M, AM 15.98 1 0.31 5 1.56 

" Seal/Sail Rock to Kydaka Point, 500 M, PM 13.98 29 10.37 10 3.58 

" Seal/Sail Rock to Kydaka Point, 800 M, AM 14.07 20 7.11 1 0.36 

" Seal/Sail Rock to Kydaka Point, Zig-Zag, AM 20.62 24 5.82 10 2.42 

29 January 1998 Seal/Sail Rock to Kydaka Point, 200 M, AM 15.22 1 0.33 32 10.51 

" Seal/Sail Rock to Kydaka Point, 500 M, AM 14.62 5 1.71 19 6.50 

" Seal/Sail Rock to Kydaka Point, 800 M, AM 14.08 19 6.75 7 2.49 

" Seal/Sail Rock to Kydaka Point, Zig-Zag, AM 21.33 9 2.11 26 6.09 

" Seal/Sail Rock to Kydaka Point, 200 M, PM 15.42 2 0.65 33 10.70 

" Seal/Sail Rock to Kydaka Point, 500 M, PM 14.54 8 2.75 48 16.51 

" Seal/Sail Rock to Kydaka Point 800 M, PM 13.98 24 8.58 1 0.36 

" Seal/Sail Rock to Kydaka Point, Zig-Zag, PM 21.81 58 13.30 28 6.42 

4 February 1998 Seal/Sail Rock to Kydaka Point, 200 M, PM 15.65 0 0.00 5 1.60 

" Seal/Sail Rock to Kydaka Point, Zig-Zag, PM 21.13 1 0.24 11 2.60 

5 February 1998 Seal/Sail Rock to Kydaka Point, 500 M, AM 15.13 0 0.00 10 3.30 

" Seal/Sail Rock to Kydaka Point, 800 M, AM 13.9 10 3.60 0 0.00 

" Seal/Sail Rock to Kydaka Point, Zig-Zag, AM 35.8 6 0.84 4 0.56 

" Seal/Sail Rock to Kydaka Point, 200 M, PM 15.75 0 0.00 8 2.54 

" Seal/Sail Rock to Kydaka Point, 500 M, PM 15.14 0 0.00 21 6.94 

" Seal/Sail Rock to Kydaka Point, 800 M, PM 14.74 1 0.34 2 0.68 

" Seal/Sail Rock to Kydaka Point, Zig-Zag, PM 24.03 0 0.00 11 2.29 

11 February 1998 Seal/Sail Rock to Kydaka Point, 500 M, AM 16.15 1 0.31 20 6.19 

" Seal/Sail Rock to Kydaka Point, 800 M, AM 15.57 6 1.93 17 5.46 

" Seal/Sail Rock to Kydaka Point, Zig-Zag, AM 22.93 14 3.05 26 5.67 

" Seal/Sail Rock to Kydaka Point, 200 M, PM 16.41 3 0.91 3 0.91 

" Seal/Sail Rock to Kydaka Point, 200 M, PM 15.9 1 0.31 0 0.00 

" Seal/Sail Rock to Kydaka Point, 500 M, PM 16.12 4 1.24 25 7.75 

" Seal/Sail Rock to Kydaka Point, 800 M, PM 14.74 1 0.34 2 0.68 

" Seal/Sail Rock to Kydaka Point, Zig-Zag, PM 23.66 28 5.92 25 5.28 

17 February 1998 Fuca Pillar to Point of Arches, 1000 M, AM 14.1 76 26.95 12 4.26 

" Fuca Pillar to Point of Arches, 700 M, AM 12.55 32 12.75 7 2.79 

" Fuca Pillar to Point of Arches (Partial), 700 M, AM 9.45 152 80.42 9 4.76 

" Tatoosh Island to Seal/Sail Rock, 1000 M, PM 17.37 1790 515.26 25 7.20 

" Tatoosh Island to Seal/Sail Rock, 500 M, AM 17.09 58 16.97 25 7.31 

18 February 1998 Kydaka Point to Waadah Island, 1000 M, PM 4.39 1 1.14 2 2.28 

" Sekui to Port Angeles, 1000 M, PM 80.04 17 1.06 119 7.43 

" Sekui to Port Angeles, 500 M, AM 81.43 2 0.12 60 3.68 

19 February 1998 Majestic Beach (nr Lyre R.) to Tatoosh Is., 880 M, PM 76.51 674 44.05 89 5.82 

" Tatoosh Island to Seal/Sail Rock, 400 M, AM 77.72 3009 193.58 220 14.15 

24 February 1998 Fuca Pillar to Point of Arches, 1000 M, AM 14.5 0 0.00 13 4.48 

" Fuca Pillar to Point of Arches, 1000 M, AM 13.78 0 0.00 14 5.08 
" Fuca Pillar to Point of Arches, 1000 M, PM 13.65 0 0.00 17 6.23 

" Fuca Pillar to Point of Arches, 1000 M, PM 14 6 2.14 14 5.00 

" Fuca Pillar to Point of Arches, 1000 M, PM 14.04 1 0.36 27 9.62 

" Fuca Pillar to Point of Arches, 200 M, AM 12.72 0 0.00 10 3.93 

" Fuca Pillar to Point of Arches, 700 M, AM 13.9 0 0.00 23 8.27 

" Fuca Pillar to Point of Arches, 700 M, AM 13.07 1 0.38 23 8.80 

" Fuca Pillar to Point of Arches, 700 M, PM 12.32 10 4.06 16 6.49 

" Fuca Pillar to Point of Arches, , 700 M, PM 13.42 2 0.75 11 4.10 

25 February 1998 Slip Point to Crescent Bay, 1200 M, AM 42.01 18 2.14 16 1.90 

Fuca Pillar to Point of Arches, 1000 M, PM 14.96 2 0.67 14 4.68 

" Fuca Pillar to Point of Arches, 1000 M, AM 14.36 3 1.04 15 5.22 

" Fuca Pillar to Point of Arches, 1000 M, PM 16.37 10 3.05 6 1.83 

" Fuca Pillar to Point of Arches, 700 M, AM 10.88 4 1.84 15 6.89 

" Fuca Pillar to Point of Arches, 700 M, PM 12.56 0 0.00 19 7.56 

" Fuca Pillar to Point of Arches, 700 M, PM 12.98 2 0.77 17 6.55 

" Skagway Rocks to Neah Bay, 700 M, PM 15.79 72 22.80 94 29.77 

3 March 1998 Point of Arches to Quilleute River, nearshore, AM 55.76 69 6.19 59 5.29 

" Point of Arches to Skagway Rocks, offshore, PM 14.09 7 2.48 10 3.55 

" Quilleute River to Point of Arches, offshore, PM 47.11 864 91.70 36 3.82 

" Skagway Rocks to Neah Bay, offshore, PM 18.95 207 54.62 15 3.96 

4 March 1998 Neah Bay to Port Angeles, 1700 M, AM 98.42 583 29.62 38 1.93 

" Port Angeles to Neah Bay, 400 M, PM 100.84 20 0.99 139 6.89 

5 March 1998 Neah Bay to Skagway Rocks, nearshore, AM 16.22 9 2.77 32 9.86 

" Point of Arches to Skagway Rocks, 400 M, AM 15.94 0 0.00 23 7.21 

" Point of Arches to Skagway Rocks, 400 M, AM 15.94 0 0.00 8 2.51 

" Point of Arches to Skagway Rocks, 400 M, AM 16.21 1 0.31 7 2.16 

" Neah Bay to Skagway Rocks, nearshore, PM 15.91 4 1.26 25 7.86 

" Point of Arches to Skagway Rocks, 400 M, AM 16.49 0 0.00 20 6.06 

10 March 1998 Ocean Shores to Point Grenville, nearshore, AM 49.01 263 26.83 32 3.26 

Westport to Willapa Bay, nearshore, AM 38.95 40 5.13 55 7.06 

" Willapa Bay to Columbia River, nearshore, AM 41.84 46 5.50 81 9.68 

" Columbia River to Willapa Bay, offshore, PM 42.91 329 38.34 197 22.96 

" Willapa Bay to Westport, offshore, PM 39.12 63 8.05 73 9.33 

13 March 1998 Outside Gray's Harbor seawall 56.15 6 0.53 67 5.97 

17 March 1998 Around Destruction Island 8.35 0 0.00 3 1.80 

" Pt. Grenville to Hoh Head, first half, offshore, AM 47.24 5 0.53 4 0.42 

" Pt. Grenville to Hoh Head, second half, offshore, AM 9.66 0 0.00 0 0.00 

" Hoh Head to Point Grenville, nearshore, PM 57.45 10 0.87 0 0.00 

18 March 1998 Inside Willapa Bay 82.98 0 0.00 32 1.93 

" Inside Willapa Bay 41 2 0.24 24 2.93 

19 March 1998 Hoh Head to Lapush, nearshore, AM 24.87 0 0.00 0 0.00 

" Lapush to Hoh Head, offshore, AM 19.24 82 21.31 3 0.78 

" Pt. Grenville to Gray's Harbor, offshore, PM 46.61 73 7.83 5 0.54 

 Total Kilometers surveyed: 2242.25 
Table 4. Date, geographic location, and length (kilometers) of transects conducted in the summer of 1998 and

associated densities of Common Murres and Marbled Murrelets along the outer coast of Washington and Strait oJuan de Fuca. 

Common Number of Common Marbled

Number of Murre Common Murre Chick Number of Murrelet

SURVEY Transect Common Density Murre Density Marbled DensityDATE Location Length (km) Murres per sq. km Chicks per sq. km Murrelets per sq. k2 June 1998 Kydaka Point to Pillar Point, 400 M AM 20.15 0 0.00 0 0.00 11 2.7

" Neah Bay to Kydaka Point, 400 M, AM 21.2 9 2.12 0 0.00 26 6.1

2 June 1998 Low Point to Pillar Point, 400 M, PM 21.45 23 5.36 0 0.00 109 25.4

" Pillar Point to Low Point, 400 M, PM 22.58 0 0.00 0 0.00 30 6.6

3 June 1998 Point of Arches to Skagway Rocks, 700 meters 12.52 97 38.74 0 0.00 2 0.8

" Skagway Rocks to Neah Bay, nearshore 15.59 43 13.79 0 0.00 2 0.6" Point of Arches to Skagway Rocks, 400 meters 16.49 36 10.92 0 0.00 6 1.8

4 June 1998 Kydaka Point to Pillar Point, nearshore 22.06 1 0.23 0 0.00 17 3.8

" Neah Bay to Kydaka Point, nearshore 19.7 7 1.78 0 0.00 32 8.1

4 June 1998 Kydaka Point to Neah Bay, offshore 19.88 16 4.02 0 0.00 22 5.5

" Pillar Point to Kydaka Point, offshore 22.63 6 1.33 0 0.00 4 0.8

4 June 1998 Kydaka Point to Pillar Point, offshore 20.46 4 0.98 0 0.00 4 0.9

" Neah Bay to Kydaka Point, offshore 21.07 16 3.80 0 0.00 17 4.0

4 June 1998 Kydaka Point to Neah Bay, nearshore 19.91 12 3.01 0 0.00 27 6.7

" Pillar Point to Neah Bay, nearshore 23.05 1 0.22 0 0.00 10 2.1

9 June 1998 Gray's Harbor - Willapa Bay, nearshore 30.31 1185 195.48 0 0.00 4 0.6

" Klipson Beach - Columbia River, nearshore 20.58 1386 336.73 0 0.00 1 0.2" Willapa Bay to Klipson Beach, nearshore 31.44 6078 966.60 0 0.00 0 0.0

9 June 1998 Columbia River - Klipson Beach, offshore 23.19 1671 360.28 0 0.00 0 0.0

" Klipson Beach - Willapa Bay, offshore 28.47 1215 213.38 0 0.00 0 0.0" Willapa Bay - Gray's Harbor, offshore 33.2 1322 199.10 0 0.00 0 0.0

10 June 1998 Gray's Harbor - Willapa Bay, offshore 18.99 1811 476.83 0 0.00 1 0.211 June 1998 Gray's Harbor - Willapa Bay, offshore 27.23 892 163.79 0 0.00 0 0.0

" Klipson Beach - Columbia River, offshore 18.8 2133 567.29 0 0.00 1 0.2" Willapa Bay - Klipson Beach, offshore 30.51 412 67.52 0 0.00 1 0.1

11 June 1998 Columbia River - Klipson Beach, nearshore 19.31 6571 1701.45 0 0.00 0 0.0

" Klipson Beach - Willapa Bay, nearshore 29 1196 206.21 0 0.00 2 0.3" Willapa Bay - Gray's Harbor, nearshore 27.01 165 30.54 0 0.00 0 0.0

16 June 1998 Seal/Sail Rock to Kydaka PT., 200 M, AM 15.15 0 0.00 0 0.00 129 42.5

" Seal/Sail Rock to Kydaka PT., 500 M, AM 14.41 10 3.47 0 0.00 41 14.2" Seal/Sail Rock to Kydaka PT., 800 M, AM 13.81 9 3.26 0 0.00 0 0.0
" Seal/Sail Rock to Kydaka PT., Zig-Zag, AM 21.34 16 3.75 0 0.00 74 17.3

16 June 1998 Seal/Sail Rock to Kydaka PT., 200 M, PM 15.72 1 0.32 0 0.00 93 29.5

" Seal/Sail Rock to Kydaka PT., 500 M, AM 14.43 4 1.39 0 0.00 8 2.7" Seal/Sail Rock to Kydaka PT., 800 M, PM 8.75 54 30.86 0 0.00 0 0.0

17 June 1998 Seal/Sail Rock to Kydaka PT., 200 M, AM 15.01 3 1.00 0 0.00 126 41.9

" Seal/Sail Rock to Kydaka PT., 500 M, AM 14.43 1 0.35 0 0.00 56 19.4" Seal/Sail Rock to Kydaka PT., 800 M, AM 13.99 19 6.79 0 0.00 11 3.9" Seal/Sail Rock to Kydaka PT., Zig-Zag, AM 20.89 20 4.79 0 0.00 70 16.7

17 June 1998 Seal/Sail Rock to Kydaka PT., 200 M, PM 15.06 4 1.33 0 0.00 125 41.5

" Seal/Sail Rock to Kydaka PT., 500 M, PM 14.5 12 4.14 0 0.00 15 5.1" Seal/Sail Rock to Kydaka PT., 800 M, AM 13.98 9 3.22 0 0.00 4 1.4" Seal/Sail Rock to Kydaka PT., Zig-Zag, PM 20.36 14 3.44 0 0.00 50 12.2

18 June 1998 Seal/Sail Rock to Kydaka PT., 200 M, AM 15.25 3 0.98 0 0.00 239 78.3

" Seal/Sail Rock to Kydaka PT., 500 M, AM 14.33 7 2.44 0 0.00 32 11.1" Seal/Sail Rock to Kydaka PT., 800 M, AM 14.3 5 1.75 0 0.00 2 0.7" Seal/Sail Rock to Kydaka PT., Zig-Zag, AM 21.49 17 3.96 0 0.00 40 9.3

18 June 1998 Seal/Sail Rock to Kydaka PT., 200 M, PM 15.11 4 1.32 0 0.00 195 64.5

" Seal/Sail Rock to Kydaka PT., 500 M, PM 14.64 6 2.05 0 0.00 7 2.3" Seal/Sail Rock to Kydaka PT., 200 M, PM 13.77 35 12.71 0 0.00 6 2.1" Seal/Sail Rock to Kydaka PT., Zig-Zag, PM 21.28 24 5.64 0 0.00 36 8.4

23 June 1998 Low Point to Pillar Point, nearshore 22.92 16 3.49 0 0.00 302 65.8

" Observatory Point to Low Point, nearshore 15.67 2 0.64 0 0.00 70 22.3" Port Angeles to Observatory Point, nearshore 19.75 25 6.33 0 0.00 111 28.1" Pillar Point to Kydaka Point, nearshore 23.38 1 0.21 0 0.00 111 23.7

23 June 1998 Kydaka Point to Pillar Point, offshore 25.8 21 4.07 0 0.00 44 8.5

" Low Point to Observatory Point, offshore 15.67 1 0.32 0 0.00 15 4.7" Observatory Point to Port Angeles, offshore 20.17 15 3.72 0 0.00 45 11.1" Pillar Point to Low Point, offshore 19.46 20 5.14 0 0.00 120 30.8

24 June 1998 Low Point to Pillar Point, offshore 22.33 8 1.79 0 0.00 136 30.4

" Observatory Point to Low Point, offshore 15.73 1 0.32 0 0.00 47 14.9" Port Angeles to Observatory Point, offshore 19.48 4 1.03 0 0.00 72 18.4

24 June 1998 Kydaka Point to Pillar Point, nearshore 23.75 5 1.05 0 0.00 130 27.3

" Low Point to Observatory Point, nearshore 15.89 1 0.31 0 0.00 93 29.2" Observatory Point to Port Angeles, nearshore 19.33 0 0.00 0 0.00 271 70.1" Pillar Point to Low Point, nearshore 22.68 8 1.76 0 0.00 283 62.3

25 June 1998 Kydaka Point to Pillar Point, nearshore 23.7 2 0.42 0 0.00 167 35.2

" Low Point to Observatory Point, nearshore 15.99 0 0.00 0 0.00 86 26.8" Observatory Point to Port Angeles, nearshore 20.2 6 1.49 0 0.00 183 45.3" Pillar Point to Low Point, nearshore 22.77 5 1.10 0 0.00 268 58.8
30 June 1998 Columbia River - Klipson Beach, nearshore 22.62 1955 432.14 0 0.00 2 0.4

" Gray's Harbor - Willapa Bay, offshore 26.71 229 42.87 0 0.00 4 0.7" Klipson Beach - Columbia River, offshore 22.06 5408 1225.75 0 0.00 3 0.6" Klipson Beach - Willapa Bay, nearshore 31.41 765 121.78 0 0.00 7 1.1" Willapa Bay - Gray's Harbor, nearshore 32.65 28 4.29 0 0.00 0 0.0" Willapa Bay - Klipson Beach, offshore 30.15 902 149.59 0 0.00 4 0.6

1 July 1998 Columbia River - Klipson Beach, offshore 22.25 2607 585.84 0 0.00 7 1.5

" Gray's Harbor - Willapa Bay, nearshore 24.53 368 75.01 0 0.00 0 0.0" Klipson Beach - Columbia River, nearshore 21.18 1950 460.34 0 0.00 3 0.7" Klipson Beach - Willapa Bay, offshore 29.86 961 160.92 0 0.00 2 0.3" Willapa Bay - Gray's Harbor, offshore 25.14 250 49.72 0 0.00 3 0.6" Willapa Bay - Klipson Beach, nearshore 32.91 575 87.36 0 0.00 2 0.3

7 July 1998 Outer Coast, Neah Bay south, 1000M, AM 14.35 96 33.45 0 0.00 2 0.7

" Outer Coast, Neah Bay south, 400M, AM 17.61 310 88.02 0 0.00 20 5.6" Outer Coast, Neah Bay south, 700M, AM 12.44 89 35.77 0 0.00 3 1.2" Outer Coast, Neah Bay south, Zig-Zag, AM 17.57 75 21.34 0 0.00 0 0.0" Outer Coast, Neah Bay south, 1000M, PM 14.22 146 51.34 0 0.00 0 0.0" Outer Coast, Neah Bay south, 400M, AM 17.14 126 36.76 0 0.00 11 3.2" Outer Coast, Neah Bay south, 700M, PM 12.61 212 84.06 0 0.00 0 0.0" Outer Coast, Neah Bay south, Zig-Zag, AM 18.42 111 30.13 0 0.00 0 0.0" Kydaka Point to Pillar Point, nearshore 23.18 6 1.29 0 0.00 78 16.8" Low Point to Observatory Point, nearshore 17.77 49 13.79 0 0.00 181 50.9" Neah Bay to Kydaka Point, nearshore 21.15 149 35.22 0 0.00 192 45.3" Observatory Point to Port Angeles, nearshore 19.88 21 5.28 0 0.00 97 24.4" Pillar Point to Low Point, nearshore 22.67 21 4.63 0 0.00 420 92.6

9 July 1998 Outer Coast, Neah Bay south, 1000M, PM 13.67 38 13.90 0 0.00 0 0.0

" Outer Coast, Neah Bay south, 400M, AM 16.61 36 10.84 0 0.00 22 6.6" Outer Coast, Neah Bay south, 700M, PM 12.8 42 16.41 0 0.00 5 1.9" Outer Coast, Neah Bay south, Zig-Zag, AM 18.43 41 11.12 0 0.00 4 1.0

16 July 1998 Columbia River - Klipson Beach, offshore 22.94 804 175.24 9 1.96 0 0.0

" Gray's Harbor - Willapa Bay, nearshore 23.15 652 140.82 6 1.30 0 0.0" Klipson Beach - Columbia River, nearshore 21.07 981 232.80 14 3.32 1 0.2" Klipson Beach - Willapa Bay, offshore 34.69 489 70.48 2 0.29 2 0.2" Willapa Bay - Gray's Harbor, offshore 22.86 412 90.11 4 0.87 0 0.0" Willapa Bay - Klipson Beach, nearshore 32.47 1695 261.01 14 2.16 2 0.3

21 July 1998 Seal/Sail Rock to Kydaka PT., 200 M, AM 14.63 26 8.89 0 0.00 54 18.4

" Seal/Sail Rock to Kydaka PT., 500 M, AM 13.89 91 32.76 0 0.00 13 4.6" Seal/Sail Rock to Kydaka PT., 800 M, PM 14.18 112 39.49 0 0.00 2 0.7" Seal/Sail Rock to Kydaka PT., Zig-Zag, AM 21.95 194 44.19 0 0.00 31 7.0
21 July 1998 Seal/Sail Rock to Kydaka PT., 200 M, PM 15.56 112 35.99 0 0.00 32 10.2

" Seal/Sail Rock to Kydaka PT., 500 M, PM 14.48 31 10.70 0 0.00 19 6.5" Seal/Sail Rock to Kydaka PT., 800 M, PM 14.57 57 19.56 0 0.00 3 1.0" Seal/Sail Rock to Kydaka PT., Zig-Zag, PM 22.57 186 41.21 0 0.00 27 5.9

22 July 1998 Seal/Sail Rock to Kydaka PT., 200 M, AM 15.57 22 7.06 0 0.00 43 13.8

" Seal/Sail Rock to Kydaka PT., 500 M, AM 14.23 94 33.03 0 0.00 5 1.7" Seal/Sail Rock to Kydaka PT., 800 M, AM 13.27 181 68.20 0 0.00 4 1.5" Seal/Sail Rock to Kydaka PT., Zig-Zag, AM 21.5 395 91.86 0 0.00 24 5.5

23 July 1998 Outer Coast, Neah Bay south, 400M, AM 16.4 49 14.94 0 0.00 6 1.8

" Outer Coast, Neah Bay south, 700M, AM 12.57 31 12.33 0 0.00 3 1.1" Outer Coast, Neah Bay south, 1000M, AM 14.19 42 14.80 0 0.00 1 0.3" Outer Coast, Neah Bay south, Zig-Zag, AM 16.59 177 53.35 0 0.00 5 1.5

28 July 1998 Columbia River - Klipson Beach, offshore 21.77 1371 314.88 7 1.61 0 0.0

" Gray's Harbor - Willapa Bay, nearshore 24.98 1222 244.60 13 2.60 0 0.0" Klipson Beach - Columbia River, nearshore 21.8 1569 359.86 74 16.97 2 0.4" Klipson Beach - Willapa Bay, offshore 26.01 401 77.09 18 3.46 2 0.3" Willapa Bay - Gray's Harbor, offshore 41.37 375 45.32 6 0.73 0 0.0" Willapa Bay - Klipson Beach, nearshore 30.91 1776 287.29 50 8.09 2 0.3

30 July 1998 Cape Alava to Point of Arches, nearshore 19.15 139 36.29 3 0.78 11 2.8

" Cape Alava to Quilleute River, offshore 35.12 531 75.60 15 2.14 1 0.1" Point of Arches to Cape Alava, offshore 16.16 142 43.94 1 0.31 0 0.0" Quilleute River to Cape Alava, nearshore 32.97 215 32.61 4 0.61 1 0.1

11 Aug 1998 Neah Bay to Kydaka Point, nearshore 19.63 4 1.02 0 0.00 10 2.511 Aug 1998 Kydaka Point to Pillar Point, nearshore 22.93 1 0.22 0 0.00 7 1.512 Aug 1998 Low Point to Observation Point, nearshore 15.95 2 0.63 0 0.00 33 10.3

" Low Point to Pillar Point, offshore 18.57 8 2.15 0 0.00 5 1.3" Observatory Point to Low Point, offshore 7.97 1 0.63 0 0.00 0 0.0" Observatory Point to Port Angeles, nearshore 18.15 9 2.48 1 0.28 18 4.9" Port Angeles to Observatory Point, offshore 16.22 101 31.13 2 0.62 1 0.3" Pillar Point to Low Point, nearshore 22.55 3 0.67 0 0.00 111 24.6

13 Aug 1998 Kydaka Point to Pillar Point, nearshore 20.52 0 0.00 0 0.00 9 2.1

" Neah Bay to Kydaka Point, nearshore 20.86 12 2.88 0 0.00 11 2.6" Pillar Point to Low Point, nearshore 24.46 0 0.00 0 0.00 182 37.2

13 Aug 1998 Low Point to Pillar Point, offshore 22.21 3 0.68 0 0.00 85 19.1

" Slip Point to Neah Bay, nearshore 30.15 8 1.33 0 0.00 16 2.6

26 Aug 1998 Kydaka Point to Neah Bay, Zig-Zag 25.47 25 4.91 2 0.39 0 0.0

" Low Point to Pillar Point, Zig-Zag 25.19 41 8.14 2 0.40 17 3.3
" Observatory Point to Low Point, Zig-Zag 20.29 41 10.10 3 0.74 3 0.7

" Port Angeles to Observatory Point, Zig-Zag 25.07 41 8.18 3 0.60 4 0.8" Pillar Point to Kydaka Point, Zig-Zag 26.71 24 4.49 4 0.75 1 0.1

27 Aug 1998 Cape Alava to Jagged Island, nearshore 31.34 14 2.23 2 0.32 6 0.9

" Cape Alava to Point of Arches, offshore 11.85 101 42.62 8 3.38 1 0.4" Fuca Pillar to Neah Bay, offshore 17.86 117 32.75 3 0.84 0 0.0" Fuca Pillar to Point of Arches, nearshore 18.84 22 5.84 1 0.27 3 0.8" Jagged Island to Cape Alava, offshore 24.51 43 8.77 9 1.84 0 0.0" Neah Bay to Fuca Pillar, nearshore 14.69 39 13.27 4 1.36 3 1.0" Point of Arches to Cape Alava, nearshore 13.08 8 3.06 0 0.00 6 2.2" Point of Arches to Fuca Pillar, offshore 17.46 33 9.45 4 1.15 4 1.1

28 Aug 1998 Kydaka Point to Pillar Point, Zig-Zag 29.31 17 2.90 1 0.17 0 0.0

" Low Point to Observatory Point, Zig-Zag 20.28 70 17.26 3 0.74 2 0.4" Neah Bay to Kydaka Point, Zig-Zag 25.41 31 6.10 2 0.39 3 0.5" Observatory Point to Port Angeles, Zig-Zag 25.49 56 10.98 7 1.37 4 0.7" Pillar Point to Low Point, Zig-Zag 38.62 95 12.30 5 0.65 45 5.8

1 Sept 1998 Kydaka Point to Pillar Point, Zig-Zag 19.5 2 0.51 0 0.00 0 0.0

" Neah Bay to Kydaka Point, Zig-Zag 22.98 9 1.96 1 0.22 6 1.3

1 Sept 1998 Fuca Pillar to Point of Arches, 400 M, PM 46.21 49 5.30 0 0.00 0 0.0

" Neah Bay to Fuca Pillar, Zig-Zag 10.36 13 6.27 0 0.00 0 0.0

2 Sept 1998 Kydaka Point to Pillar Point, Zig-Zag 1.43 16 55.94 2 6.99 1 3.5

" Low Point to Observatory Point, Zig-Zag 7.21 4 2.77 0 0.00 0 0.0" Pillar Point to Low Point, Zig-Zag 15.41 16 5.19 0 0.00 0 0.0

2 Sept 1998 Low Point to Observatory Point, Zig-Zag 7.46 3 2.01 0 0.00 2 1.3

" Observatory Point to Port Angeles, Zig-Zag 20.75 3 0.72 0 0.00 2 0.4

 Total Kilometers Surveyed: 3501.96 
Table 5. Date, geographic location, and length (kilometers) of transects conducted in the winter of 1998-

1999 and associated densities of Common Murres and Marbled Murrelets along the Strait of Juan de

Fuca. 

Number of Density of Number of Density of

Distance Time of Transect Common Common Marbled Marbled

Survey from Day (AM Length Murres Murres per Murrelets

Murrelets

per

Date Transect Location shore (m) or PM) (Km) Observed Km2 Observed Km2

17 February 1999 Seal/Sail Rock to Pillar Point 200 AM 15.68 0 0.00 1 0.32

17 February 1999 Seal/Sail Rock to Pillar Point 200 PM 16.81 4 1.19 0 0.00

17 February 1999 Seal/Sail Rock to Pillar Point 500 AM 14.46 0 0.00 0 0.00

17 February 1999 Seal/Sail Rock to Pillar Point 800 PM 13.97 8 2.86 0 0.00

17 February 1999 Seal/Sail Rock to Pillar Point Zig-Zag PM 24.86 15 3.02 4 0.80

19 February 1999 Seal/Sail Rock to Pillar Point 200 PM 18.28 0 0.00 3 0.82

19 February 1999 Seal/Sail Rock to Pillar Point 500 AM 14.59 1 0.34 3 1.03

19 February 1999 Seal/Sail Rock to Pillar Point 800 AM 13.82 43 15.56 1 0.36

19 February 1999 Seal/Sail Rock to Pillar Point 1200 AM 13.53 14 5.17 1 0.37

19 February 1999 Seal/Sail Rock to Pillar Point Zig-Zag AM 24.11 24 4.98 8 1.66

19 February 1999 Seal/Sail Rock to Pillar Point 800 PM 13.90 11 3.96 0 0.00

19 February 1999 Seal/Sail Rock to Pillar Point 1200 PM 13.27 43 16.20 1 0.38

19 February 1999 Seal/Sail Rock to Pillar Point Zig-Zag PM 24.62 33 6.70 1 0.20

04 March 1999 Seal/Sail Rock to Pillar Point 200 AM 15.42 0 0.00 4 1.30

04 March 1999 Seal/Sail Rock to Pillar Point 500 AM 14.47 56 19.35 1 0.35

04 March 1999 Seal/Sail Rock to Pillar Point Zig-Zag AM 26.19 28 5.35 6 1.15

04 March 1999 Seal/Sail Rock to Pillar Point 200 PM 16.78 0 0.00 5 1.49

04 March 1999 Seal/Sail Rock to Pillar Point 1200 AM 16.74 12 3.58 0 0.00

04 March 1999 Seal/Sail Rock to Pillar Point 500 PM 7.21 0 0.00 1 0.69

05 March 1999 Seal/Sail Rock to Pillar Point 1200 AM 13.26 20 7.54 0 0.00

05 March 1999 Seal/Sail Rock to Pillar Point 200 PM 21.24 0 0.00 12 2.82

05 March 1999 Seal/Sail Rock to Pillar Point 200 AM 15.25 1 0.33 14 4.59

05 March 1999 Seal/Sail Rock to Pillar Point 500 PM 23.97 49 10.22 2 0.42

05 March 1999 Seal/Sail Rock to Pillar Point 500 PM 15.19 6 1.97 1 0.33

05 March 1999 Seal/Sail Rock to Pillar Point 800 AM 14.43 33 11.43 1 0.35

05 March 1999 Seal/Sail Rock to Pillar Point 800 PM 22.60 29 6.42 0 0.00

05 March 1999 Seal/Sail Rock to Pillar Point Zig-Zag AM 23.87 63 13.20 7 1.47

10 March 1999 Seal/Sail Rock to Pillar Point 1200 AM 13.00 44 16.92 1 0.38

10 March 1999 Seal/Sail Rock to Pillar Point 200 AM 14.72 0 0.00 2 0.68

10 March 1999 Seal/Sail Rock to Pillar Point 500 AM 15.29 0 0.00 1 0.33

10 March 1999 Seal/Sail Rock to Pillar Point 800 AM 13.65 15 5.49 0 0.00

10 March 1999 Seal/Sail Rock to Pillar Point Zig-Zag AM 25.13 14 2.79 0 0.00

10 March 1999 Seal/Sail Rock to Pillar Point 200 PM 22.36 0 0.00 2 0.45

10 March 1999 Seal/Sail Rock to Pillar Point 500 PM 20.66 1 0.24 0 0.00

10 March 1999 Seal/Sail Rock to Pillar Point Zig-Zag PM 31.18 35 5.61 5 0.80

11 March 1999 Seal/Sail Rock to Pillar Point 1200 AM 13.32 69 25.90 2 0.75

11 March 1999 Seal/Sail Rock to Pillar Point 200 AM 15.89 0 0.00 0 0.00

11 March 1999 Seal/Sail Rock to Pillar Point 800 AM 13.99 58 20.73 0 0.00

17 March 1999 Seal/Sail Rock to Pillar Point 200 AM 14.95 0 0.00 0 0.00

17 March 1999 Seal/Sail Rock to Pillar Point 500 AM 14.64 3 1.02 0 0.00

17 March 1999 Seal/Sail Rock to Pillar Point 800 AM 14.00 1 0.36 1 0.36

17 March 1999 Seal/Sail Rock to Pillar Point 1200 PM 13.23 5 1.89 0 0.00

18 March 1999 Seal/Sail Rock to Pillar Point 1200 AM 13.19 13 4.93 0 0.00

18 March 1999 Seal/Sail Rock to Pillar Point 500 AM 14.40 0 0.00 0 0.00

18 March 1999 Seal/Sail Rock to Pillar Point 800 AM 13.99 2 0.71 0 0.00

18 March 1999 Seal/Sail Rock to Pillar Point Zig-Zag AM 23.26 67 14.40 2 0.43

 Total kilometers surveyed: 789.37
Table 6. Dates, locations and lengths of transects used in statistical power analyses of Marbled Murrelet

density in relation to location, year, season, time of day and distance to shore.

Survey Date Location of transect

Strait of

Juan de

Fuca or

outer

coast

Transect

length

(km)

Number

of

Common

Murres

Common

Murre

Density

per km2

Number

of

Marbled

Murrelets

Common

Murre

Density

per km2

01 August 1995 Neah Bay to Pillar Point, 200 M, AM S 49.08 0 0.00 23 2.34

01 August 1995 Neah Bay to Pillar Point, 400 M, PM S 42.21 0 0.00 14 1.66

01 August 1995 Neah Bay to Pillar Point, 800 M, AM S 41.64 0 0.00 4 0.48

01 August 1995 Neah Bay to Pillar Point, 1200 M, AM S 42.18 0 0.00 1 0.12

02 August 1995 Neah Bay to Pillar Point, 200 M, AM (Partial) S 16.43 0 0.00 12 3.65

02 August 1995 Neah Bay to Pillar Point, 800 M, PM S 43.08 0 0.00 6 0.70

08 August 1995 Neah Bay to Pillar Point, 200 M, PM (Partial) S 29.20 0 0.00 1 0.17

09 August 1995 Neah Bay to Sekiu, 200 M, AM S 35.35 0 0.00 40 5.66

09 August 1995 Neah Bay to Sekiu, 400 M, PM S 34.21 0 0.00 40 5.85

09 August 1995 Neah Bay to Sekiu, 800 M, PM S 30.99 0 0.00 5 0.81

09 August 1995 Neah Bay to Sekiu, 1200 M, AM S 28.77 0 0.00 0 0.00

10 August 1995 Neah Bay to Sekiu, 200 M, AM S 32.94 0 0.00 17 2.58

10 August 1995 Neah Bay to Sekiu, 200 M, PM S 34.64 0 0.00 27 3.90

10 August 1995 Neah Bay to Sekiu, 400 M, AM S 31.54 0 0.00 19 3.01

10 August 1995 Neah Bay to Sekiu, 800 M, PM S 29.40 0 0.00 0 0.00

10 August 1995 Neah Bay to Sekiu, 1200 M, PM S 29.34 0 0.00 0 0.00

11 August 1995 Neah Bay to Sekiu, 400 M, AM (length?) S 56.29 0 0.00 28 2.49

11 August 1995 Neah Bay to Sekiu, 800 M, AM (Partial) S 17.72 0 0.00 7 1.98

20 August 1995 Tatoosh Island to Cape Alava, 400 M, PM OC 26.24 0 0.00 11 2.10

21 August 1995 Tatoosh Island to Cape Alava, 400 M, PM OC 26.05 0 0.00 12 2.30

22 August 1995 Tatoosh Island to Cape Alava, 400 M, AM OC 26.73 0 0.00 20 3.74

22 August 1995 Tatoosh Island to Cape Alava, 1200 M, PM OC 25.89 0 0.00 0 0.00

23 August 1995 Tatoosh Island to Cape Alava, 400 M, AM OC 26.90 0 0.00 19 3.53

23 August 1995 Tatoosh Island to Cape Alava, 1200 M, AM OC 26.05 0 0.00 0 0.00

23 August 1995 Tatoosh Island to Cape Alava, 1200 M, PM OC 25.88 0 0.00 0 0.00

24 August 1995 Tatoosh Island to Cape Alava, 1200 M, AM OC 28.79 0 0.00 0 0.00

12 Mar 1996 Sekiu to Neah Bay S 31.51 0 0.00 7 0.98

12 Mar 1996 Sekiu to Neah Bay S 29.83 48 17.27 5 1.80

12 Mar 1996 Sekiu to Neah Bay S 27.00 21 6.67 7 2.22

12 Mar 1996 Sekiu to Neah Bay S 28.08 85 28.07 0 0.00

13 Mar 1996 Sekiu to Neah Bay S 32.40 4 1.36 33 11.19

13 Mar 1996 Sekiu to Neah Bay S 31.55 0 0.00 21 4.37

13 Mar 1996 Sekiu to Neah Bay S 26.48 7 2.17 16 4.95

13 Mar 1996 Sekiu to Neah Bay S 27.54 11 3.53 1 0.32

14 Mar 1996 Sekiu to Neah Bay S 31.69 0 0.00 40 8.72

14 Mar 1996 Sekiu to Neah Bay S 29.42 0 0.00 11 3.35

14 Mar 1996 Sekiu to Neah Bay S 26.40 117 36.79 0 0.00

14 Mar 1996 Sekiu to Neah Bay S 26.32 16 4.96 5 1.55

23 May 1996 Sekiu to Neah Bay S 13.95 19 6.74 3 1.06

23 May 1996 Sekiu to Neah Bay S 14.08 23 26.20 9 10.25

23 May 1996 Sekiu to Neah Bay S 14.29 6 2.39 5 1.99

23 May 1996 Sekiu to Neah Bay S 14.28 9 3.10 7 2.41

23 May 1996 Sekiu to Neah Bay S 15.07 40 8.45 3 0.63

23 May 1996 Sekiu to Neah Bay S 14.98 9 4.76 2 1.06
23 May 1996 Sekiu to Neah Bay S 18.14 46 15.60 21 7.12

23 May 1996 Sekiu to Neah Bay S 18.32 8 2.90 5 1.81

24 July 1996 Seal/Sail Rock to Kydaka Point S 13.79 8 2.85 2 0.71

24 July 1996 Seal/Sail Rock to Kydaka Point S 14.24 18 6.47 0 0.00

24 July 1996 Seal/Sail Rock to Kydaka Point S 15.03 12 4.29 0 0.00

24 July 1996 Seal/Sail Rock to Kydaka Point S 17.67 17 6.23 1 0.37

24 July 1996 Seal/Sail Rock to Kydaka Point S 17.89 14 5.50 0 0.00

25 July 1996 Seal/Sail Rock to Kydaka Point S 11.59 62 25.16 18 7.31

25 July 1996 Seal/Sail Rock to Kydaka Point S 14.24 30 11.48 4 1.53

25 July 1996 Seal/Sail Rock to Kydaka Point S 14.32 12 4.47 1 0.37

25 July 1996 Seal/Sail Rock to Kydaka Point S 15.00 16 5.35 0 0.00

25 July 1996 Seal/Sail Rock to Kydaka Point S 18.00 18 6.27 7 2.44

25 July 1996 Seal/Sail Rock to Kydaka Point S 17.88 33 10.08 3 0.92

26 July 1996 Seal/Sail Rock to Kydaka Point S 13.20 16 7.35 13 5.97

13 February 1997 Neah Bay to Slip Point S 31.40 0 0.00 44 17.52

13 February 1997 Neah Bay to Slip Point S 30.10 0 0.00 9 3.47

13 February 1997 Neah Bay to Slip Point S 29.69 0 0.00 1 0.24

13 February 1997 Neah Bay to Slip Point S 27.36 0 0.00 2 0.80

11 June 1997 Fuca Pillar to Point of Arches OC 10.42 39 18.71 2 0.53

11 June 1997 Fuca Pillar to Point of Arches OC 17.28 140 40.51 5 0.62

12 June 1997 Fuca Pillar to Point of Arches OC 16.98 53 15.61 8 2.56

12 June 1997 Fuca Pillar to Point of Arches OC 16.73 73 21.82 10 2.29

12 June 1997 Fuca Pillar to Point of Arches OC 12.52 107 42.73 3 0.35

12 June 1997 Fuca Pillar to Point of Arches OC 12.27 78 31.78 3 0.47

12 June 1997 Fuca Pillar to Point of Arches OC 16.06 81 25.22 6 1.19

12 June 1997 Fuca Pillar to Point of Arches OC 13.91 38 13.66 0 0.00

12 June 1997 Fuca Pillar to Point of Arches OC 15.74 37 11.75 7 2.98

12 June 1997 Fuca Pillar to Point of Arches OC 16.41 119 36.26 0 0.00

24 June 1997 Fuca Pillar to Point of Arches OC 16.53 102 30.85 6 0.97

24 June 1997 Fuca Pillar to Point of Arches OC 17.08 72 21.08 17 4.03

24 June 1997 Fuca Pillar to Point of Arches OC 12.46 44 17.66 2 0.57

24 June 1997 Fuca Pillar to Point of Arches OC 12.81 129 50.35 3 0.30

24 June 1997 Fuca Pillar to Point of Arches OC 14.57 138 47.36 0 0.00

24 June 1997 Fuca Pillar to Point of Arches OC 16.10 109 33.85 0 0.00

24 June 1997 Fuca Pillar to Point of Arches OC 17.41 113 32.45 2 0.31

24 June 1997 Fuca Pillar to Point of Arches OC 19.21 144 37.48 2 0.27

25 June 1997 Fuca Pillar to Point of Arches OC 16.31 111 34.03 1 0.15

25 June 1997 Fuca Pillar to Point of Arches OC 12.64 29 11.47 1 0.44

25 June 1997 Fuca Pillar to Point of Arches OC 14.74 244 82.77 0 0.00

25 June 1997 Fuca Pillar to Point of Arches OC 17.93 99 27.61 2 0.36

09 July 1997 Fuca Pillar to Point of Arches OC 18.08 240 66.37 6 0.45

09 July 1997 Fuca Pillar to Point of Arches OC 16.26 256 78.72 27 1.71

09 July 1997 Fuca Pillar to Point of Arches OC 9.42 65 34.50 11 1.59

09 July 1997 Fuca Pillar to Point of Arches OC 10.59 130 61.38 5 0.41

09 July 1997 Fuca Pillar to Point of Arches OC 14.07 144 51.17 12 1.17

09 July 1997 Fuca Pillar to Point of Arches OC 14.22 191 67.16 3 0.22

09 July 1997 Fuca Pillar to Point of Arches OC 16.04 277 86.35 15 0.87

09 July 1997 Fuca Pillar to Point of Arches OC 17.00 224 65.88 14 1.06

10 July 1997 Fuca Pillar to Point of Arches OC 11.44 160 69.93 4 0.29

10 July 1997 Fuca Pillar to Point of Arches OC 15.97 92 28.80 27 4.69
10 July 1997 Fuca Pillar to Point of Arches OC 13.03 103 39.52 3 0.38

10 July 1997 Fuca Pillar to Point of Arches OC 14.04 171 60.90 6 0.49

10 July 1997 Fuca Pillar to Point of Arches OC 13.97 93 33.29 12 1.80

10 July 1997 Fuca Pillar to Point of Arches OC 16.82 160 47.56 17 1.79

22 July 1997 Seal Rock to Kydaka Point S 14.48 1 0.35 30 434.40

22 July 1997 Seal Rock to Kydaka Point S 14.40 11 3.82 8 10.47

22 July 1997 Seal Rock to Kydaka Point S 14.14 27 9.55 9 4.71

22 July 1997 Seal Rock to Kydaka Point S 14.74 9 3.05 1 1.64

22 July 1997 Seal Rock to Kydaka Point S 14.39 31 10.77 3 1.39

22 July 1997 Seal Rock to Kydaka Point S 14.28 34 11.90 1 0.42

22 July 1997 Seal Rock to Kydaka Point S 17.30 52 15.03 0 0.00

22 July 1997 Seal Rock to Kydaka Point S 16.72 52 15.55 12 3.86

23 July 1997 Seal Rock to Kydaka Point S 14.68 324 110.35 9 0.41

23 July 1997 Seal Rock to Kydaka Point S 14.10 69 24.47 1 0.20

23 July 1997 Seal Rock to Kydaka Point S 14.10 256 90.78 2 0.11

23 July 1997 Seal Rock to Kydaka Point S 21.03 131 31.15 2 0.32

24 July 1997 Seal Rock to Kydaka Point S 15.04 41 13.63 19 6.97

24 July 1997 Seal Rock to Kydaka Point S 15.03 14 4.66 23 24.69

24 July 1997 Seal Rock to Kydaka Point S 14.28 159 55.67 5 0.45

24 July 1997 Seal Rock to Kydaka Point S 14.33 51 17.79 4 1.12

24 July 1997 Seal Rock to Kydaka Point S 13.93 42 15.08 0 0.00

24 July 1997 Seal Rock to Kydaka Point S 14.00 29 10.36 0 0.00

24 July 1997 Seal Rock to Kydaka Point S 19.68 208 52.85 16 1.51

24 July 1997 Seal Rock to Kydaka Point S 20.78 183 44.03 8 0.91

25 July 1997 Seal Rock to Kydaka Point S 14.05 115 40.93 2 0.24

19 Aug 1997 Seal Rock to Kydaka Point S 14.63 40 13.67 13 4.75

19 Aug 1997 Seal Rock to Kydaka Point S 15.52 17 5.48 1 0.91

19 Aug 1997 Seal Rock to Kydaka Point S 14.67 40 13.63 1 0.37

19 Aug 1997 Seal Rock to Kydaka Point S 18.98 58 15.28 2 0.65

20 Aug 1997 Seal Rock to Kydaka Point S 14.99 31 10.34 1 0.48

20 Aug 1997 Seal Rock to Kydaka Point S 20.69 67 16.19 4 1.24

25 Aug 1997 Seal Rock to Kydaka Point S 14.99 55 18.35 6 1.64

25 Aug 1997 Seal Rock to Kydaka Point S 14.87 26 8.74 3 1.72

25 Aug 1997 Seal Rock to Kydaka Point S 14.17 10 3.53 0 0.00

25 Aug 1997 Seal Rock to Kydaka Point S 13.73 25 9.10 0 0.00

25 Aug 1997 Seal Rock to Kydaka Point S 13.89 19 6.84 0 0.00

25 Aug 1997 Seal Rock to Kydaka Point S 20.60 25 6.07 3 2.47

22 January 1998 Seal/Sail Rock to Kydaka Point, 200 M, AM S 15.52 1 0.32 10 3.22

22 January 1998 Seal/Sail Rock to Kydaka Point, 500 M, AM S 15.11 10 3.31 10 3.31

27 January 1998 Seal/Sail Rock to Kydaka Point, 200 M, AM S 15.98 1 0.31 5 1.56

27 January 1998 Seal/Sail Rock to Kydaka Point, 500 M, PM S 13.98 29 10.37 10 3.58

27 January 1998 Seal/Sail Rock to Kydaka Point, 800 M, AM S 14.07 20 7.11 1 0.36

27 January 1998 Seal/Sail Rock to Kydaka Point, Zig-Zag, AM S 20.62 24 5.82 10 2.42

29 January 1998 Seal/Sail Rock to Kydaka Point, 200 M, AM S 15.22 1 0.33 32 10.51

29 January 1998 Seal/Sail Rock to Kydaka Point, 200 M, PM S 15.42 2 0.65 33 10.70

29 January 1998 Seal/Sail Rock to Kydaka Point, 500 M, AM S 14.62 5 1.71 19 6.50

29 January 1998 Seal/Sail Rock to Kydaka Point, 500 M, PM S 14.54 8 2.75 48 16.51

29 January 1998 Seal/Sail Rock to Kydaka Point, 800 M, AM S 14.08 19 6.75 7 2.49

29 January 1998 Seal/Sail Rock to Kydaka Point 800 M, PM S 13.98 24 8.58 1 0.36

29 January 1998 Seal/Sail Rock to Kydaka Point, Zig-Zag, AM S 21.33 9 2.11 26 6.09
29 January 1998 Seal/Sail Rock to Kydaka Point, Zig-Zag, PM S 21.81 58 13.30 28 6.42

04 February 1998 Seal/Sail Rock to Kydaka Point, 200 M, PM S 15.65 0 0.00 5 1.60

04 February 1998 Seal/Sail Rock to Kydaka Point, Zig-Zag, PM S 21.13 1 0.24 11 2.60

05 February 1998 Seal/Sail Rock to Kydaka Point, 200 M, PM S 15.75 0 0.00 8 2.54

05 February 1998 Seal/Sail Rock to Kydaka Point, 500 M, AM S 15.13 0 0.00 10 3.30

05 February 1998 Seal/Sail Rock to Kydaka Point, 500 M, PM S 15.14 0 0.00 21 6.94

05 February 1998 Seal/Sail Rock to Kydaka Point, 800 M, AM S 13.90 10 3.60 0 0.00

05 February 1998 Seal/Sail Rock to Kydaka Point, 800 M, PM S 14.74 1 0.34 2 0.68

05 February 1998 Seal/Sail Rock to Kydaka Point, Zig-Zag, AM S 35.80 6 0.84 4 0.56

05 February 1998 Seal/Sail Rock to Kydaka Point, Zig-Zag, PM S 24.03 0 0.00 11 2.29

11 February 1998 Seal/Sail Rock to Kydaka Point, 200 M, PM S 15.90 1 0.31 0 0.00

11 February 1998 Seal/Sail Rock to Kydaka Point, 200 M, PM S 16.41 3 0.91 3 0.91

11 February 1998 Seal/Sail Rock to Kydaka Point, 500 M, AM S 16.15 1 0.31 20 6.19

11 February 1998 Seal/Sail Rock to Kydaka Point, 500 M, PM S 16.12 4 1.24 25 7.75

11 February 1998 Seal/Sail Rock to Kydaka Point, 800 M, AM S 15.57 6 1.93 17 5.46

11 February 1998 Seal/Sail Rock to Kydaka Point, 800 M, PM S 14.74 1 0.34 2 0.68

11 February 1998 Seal/Sail Rock to Kydaka Point, Zig-Zag, AM S 22.93 14 3.05 26 5.67

11 February 1998 Seal/Sail Rock to Kydaka Point, Zig-Zag, PM S 23.66 28 5.92 25 5.28

17 February 1998

Fuca Pillar to Point of Arches (Partial), 700 M,

AM OC 9.45 152 80.42 9 4.76

17 February 1998 Fuca Pillar to Point of Arches, 700 M, AM OC 12.55 32 12.75 7 2.79

17 February 1998 Fuca Pillar to Point of Arches, 1000 M, AM OC 14.10 76 26.95 12 4.26

18 February 1998 Kydaka Point to Waadah Island, 1000 M, PM OC 4.39 1 1.14 2 2.28

24 February 1998 Fuca Pillar to Point of Arches, 200 M, AM OC 12.72 0 0.00 10 3.93

24 February 1998 Fuca Pillar to Point of Arches, 700 M, AM OC 13.90 0 0.00 23 8.27

24 February 1998 Fuca Pillar to Point of Arches, 700 M, AM OC 13.07 1 0.38 23 8.80

24 February 1998 Fuca Pillar to Point of Arches, 700 M, PM OC 13.42 2 0.75 11 4.10

24 February 1998 Fuca Pillar to Point of Arches, 700 M, PM OC 12.32 10 4.06 16 6.49

24 February 1998 Fuca Pillar to Point of Arches, 1000 M, AM OC 13.78 0 0.00 14 5.08

24 February 1998 Fuca Pillar to Point of Arches, 1000 M, AM OC 14.50 0 0.00 13 4.48

24 February 1998 Fuca Pillar to Point of Arches, 1000 M, PM OC 14.04 1 0.36 27 9.62

24 February 1998 Fuca Pillar to Point of Arches, 1000 M, PM OC 14.00 6 2.14 14 5.00

24 February 1998 Fuca Pillar to Point of Arches, 1000 M, PM OC 13.65 0 0.00 17 6.23

25 February 1998 Fuca Pillar to Point of Arches, 700 M, AM OC 10.88 4 1.84 15 6.89

25 February 1998 Fuca Pillar to Point of Arches, 700 M, PM OC 12.56 0 0.00 19 7.56

25 February 1998 Fuca Pillar to Point of Arches, 700 M, PM OC 12.98 2 0.77 17 6.55

25 February 1998 Fuca Pillar to Point of Arches, 1000 M, AM OC 14.36 3 1.04 15 5.22

25 February 1998 Fuca Pillar to Point of Arches, 1000 M, PM OC 14.96 2 0.67 14 4.68

25 February 1998 Fuca Pillar to Point of Arches, 1000 M, PM OC 16.37 10 3.05 6 1.83

02 June 1998 Neah Bay to Kydaka Point, 500 M, AM S 21.20 9 2.12 26 6.13

03 June 1998 Point of Arches to Skagway Rocks, 500 M, AM OC 16.49 36 10.92 6 1.82

03 June 1998 Point of Arches to Skagway Rocks, 700 M, PM OC 12.52 97 38.74 2 0.80

04 June 1998 Neah Bay to Kydaka Point, 500 M, PM S 19.70 7 1.78 32 8.12

04 June 1998 Kydaka Point to Neah Bay, 500 M, PM S 19.91 12 3.01 27 6.78

04 June 1998 Kydaka Point to Neah Bay, 1200 M, AM S 19.88 16 4.02 22 5.53

04 June 1998 Neah Bay to Kydaka Point, 1200 M, PM S 21.07 16 3.80 17 4.03

16 June 1998 Seal/Sail Rock to Kydaka PT., 200 M, AM S 15.15 0 0.00 129 42.57

16 June 1998 Seal/Sail Rock to Kydaka PT., 200 M, PM S 15.72 1 0.32 93 29.58

16 June 1998 Seal/Sail Rock to Kydaka PT., 500 M, AM S 14.43 4 1.39 8 2.77

16 June 1998 Seal/Sail Rock to Kydaka PT., 500 M, AM S 14.41 10 3.47 41 14.23

16 June 1998 Seal/Sail Rock to Kydaka PT., 800 M, AM S 13.81 9 3.26 0 0.00
16 June 1998 Seal/Sail Rock to Kydaka PT., 800 M, PM S 8.75 54 30.86 0 0.00

16 June 1998 Seal/Sail Rock to Kydaka PT., Zig-Zag, AM S 21.34 16 3.75 74 17.34

17 June 1998 Seal/Sail Rock to Kydaka PT., 200 M, AM S 15.01 3 1.00 126 41.97

17 June 1998 Seal/Sail Rock to Kydaka PT., 200 M, PM S 15.06 4 1.33 125 41.50

17 June 1998 Seal/Sail Rock to Kydaka PT., 500 M, AM S 14.43 1 0.35 56 19.40

17 June 1998 Seal/Sail Rock to Kydaka PT., 500 M, PM S 14.50 12 4.14 15 5.17

17 June 1998 Seal/Sail Rock to Kydaka PT., 800 M, AM S 13.99 19 6.79 11 3.93

17 June 1998 Seal/Sail Rock to Kydaka PT., 800 M, AM S 13.98 9 3.22 4 1.43

17 June 1998 Seal/Sail Rock to Kydaka PT., Zig-Zag, AM S 20.89 20 4.79 70 16.75

17 June 1998 Seal/Sail Rock to Kydaka PT., Zig-Zag, PM S 20.36 14 3.44 50 12.28

18 June 1998 Seal/Sail Rock to Kydaka PT., 200 M, AM S 15.25 3 0.98 239 78.36

18 June 1998 Seal/Sail Rock to Kydaka PT., 200 M, PM S 15.11 4 1.32 195 64.53

18 June 1998 Seal/Sail Rock to Kydaka PT., 200 M, PM S 13.77 35 12.71 6 2.18

18 June 1998 Seal/Sail Rock to Kydaka PT., 500 M, AM S 14.33 7 2.44 32 11.17

18 June 1998 Seal/Sail Rock to Kydaka PT., 500 M, PM S 14.64 6 2.05 7 2.39

18 June 1998 Seal/Sail Rock to Kydaka PT., Zig-Zag, AM S 21.49 17 3.96 40 9.31

18 June 1998 Seal/Sail Rock to Kydaka PT., Zig-Zag, PM S 21.28 24 5.64 36 8.46

07 July 1998 Outer Coast, Neah Bay south, 400M, AM OC 17.61 310 88.02 20 5.68

07 July 1998 Outer Coast, Neah Bay south, 400M, AM OC 17.14 126 36.76 11 3.21

07 July 1998 Outer Coast, Neah Bay south, 700M, AM OC 12.44 89 35.77 3 1.21

07 July 1998 Outer Coast, Neah Bay south, 700M, PM OC 12.61 212 84.06 0 0.00

07 July 1998 Outer Coast, Neah Bay south, 1000M, AM OC 14.35 96 33.45 2 0.70

07 July 1998 Outer Coast, Neah Bay south, 1000M, PM OC 14.22 146 51.34 0 0.00

07 July 1998 Outer Coast, Neah Bay south, Zig-Zag, AM OC 17.57 75 21.34 0 0.00

07 July 1998 Outer Coast, Neah Bay south, Zig-Zag, AM OC 18.42 111 30.13 0 0.00

09 July 1998 Outer Coast, Neah Bay south, 400M, AM OC 16.61 36 10.84 22 6.62

09 July 1998 Outer Coast, Neah Bay south, 700M, PM OC 12.80 42 16.41 5 1.95

09 July 1998 Outer Coast, Neah Bay south, 1000M, PM OC 13.67 38 13.90 0 0.00

09 July 1998 Outer Coast, Neah Bay south, Zig-Zag, AM OC 18.43 41 11.12 4 1.09

18 July 1998 Seal/Sail Rock to Kydaka PT., 800 M, AM S 14.30 5 1.75 2 0.70

21 July 1998 Seal/Sail Rock to Kydaka PT., 200 M, AM S 14.63 26 8.89 54 18.46

21 July 1998 Seal/Sail Rock to Kydaka PT., 200 M, PM S 15.56 112 35.99 32 10.28

21 July 1998 Seal/Sail Rock to Kydaka PT., 500 M, AM S 13.89 91 32.76 13 4.68

21 July 1998 Seal/Sail Rock to Kydaka PT., 500 M, PM S 14.48 31 10.70 19 6.56

21 July 1998 Seal/Sail Rock to Kydaka PT., 800 M, PM S 14.57 57 19.56 3 1.03

21 July 1998 Seal/Sail Rock to Kydaka PT., 800 M, PM S 14.18 112 39.49 2 0.71

21 July 1998 Seal/Sail Rock to Kydaka PT., Zig-Zag, AM S 21.95 194 44.19 31 7.06

21 July 1998 Seal/Sail Rock to Kydaka PT., Zig-Zag, PM S 22.57 186 41.21 27 5.98

22 July 1998 Seal/Sail Rock to Kydaka PT., 200 M, AM S 15.57 22 7.06 43 13.81

22 July 1998 Seal/Sail Rock to Kydaka PT., 500 M, AM S 14.23 94 33.03 5 1.76

22 July 1998 Seal/Sail Rock to Kydaka PT., 800 M, AM S 13.27 181 68.20 4 1.51

22 July 1998 Seal/Sail Rock to Kydaka PT., Zig-Zag, AM S 21.50 395 91.86 24 5.58

23 July 1998 Outer Coast, Neah Bay south, 400M, AM OC 16.40 49 14.94 6 1.83

23 July 1998 Outer Coast, Neah Bay south, 700M, AM OC 12.57 31 12.33 3 1.19

23 July 1998 Outer Coast, Neah Bay south, 1000M, AM OC 14.19 42 14.80 1 0.35

23 July 1998 Outer Coast, Neah Bay south, Zig-Zag, AM OC 16.59 177 53.35 5 1.51

11 Aug 1998 Neah Bay to Kydaka Point, 500M, AM S 19.63 4 1.02 10 2.55

13 Aug 1998 Neah Bay to Kydaka Point, 500M, AM S 20.86 12 2.88 11 2.64

26 Aug 1998 Kydaka Point to Neah Bay, Zig-Zag, PM S 25.47 25 4.91 0 0.00

27 Aug 1998 Fuca Pillar to Point of Arches, 400 M, AM OC 18.84 22 5.84 3 0.80
27 Aug 1998 Point of Arches to Fuca Pillar, 1000 M, PM OC 17.46 33 9.45 4 1.15

28 Aug 1998 Neah Bay to Kydaka Point, Zig-Zag, AM S 25.41 31 6.10 3 0.59

01 Sept 1998 Fuca Pillar to Point of Arches, 400 M, PM OC 46.21 49 5.30 0 0.00

01 Sept 1998 Neah Bay to Kydaka Point, Zig-Zag, AM S 22.98 9 1.96 6 1.31

17 February 1999 Seal/Sail Rock to Kydaka Point S 15.68 0 0.00 1 0.32

17 February 1999 Seal/Sail Rock to Kydaka Point S 16.81 4 1.19 0 0.00

17 February 1999 Seal/Sail Rock to Kydaka Point S 14.46 0 0.00 0 0.00

17 February 1999 Seal/Sail Rock to Kydaka Point S 13.97 8 2.86 0 0.00

17 February 1999 Seal/Sail Rock to Kydaka Point S 24.86 15 3.02 4 0.80

19 February 1999 Seal/Sail Rock to Kydaka Point S 18.28 0 0.00 3 0.82

19 February 1999 Seal/Sail Rock to Kydaka Point S 14.59 1 0.34 3 1.03

19 February 1999 Seal/Sail Rock to Kydaka Point S 13.82 43 15.56 1 0.36

19 February 1999 Seal/Sail Rock to Kydaka Point S 13.53 14 5.17 1 0.37

19 February 1999 Seal/Sail Rock to Kydaka Point S 24.11 24 4.98 8 1.66

19 February 1999 Seal/Sail Rock to Kydaka Point S 13.90 11 3.96 0 0.00

19 February 1999 Seal/Sail Rock to Kydaka Point S 13.27 43 16.20 1 0.38

19 February 1999 Seal/Sail Rock to Kydaka Point S 24.62 33 6.70 1 0.20

04 March 1999 Seal/Sail Rock to Kydaka Point S 15.42 0 0.00 4 1.30

04 March 1999 Seal/Sail Rock to Kydaka Point S 14.47 56 19.35 1 0.35

04 March 1999 Seal/Sail Rock to Kydaka Point S 26.19 28 5.35 6 1.15

04 March 1999 Seal/Sail Rock to Kydaka Point S 16.78 0 0.00 5 1.49

04 March 1999 Seal/Sail Rock to Kydaka Point S 16.74 12 3.58 0 0.00

04 March 1999 Seal/Sail Rock to Kydaka Point S 7.21 0 0.00 1 0.69

05 March 1999 Seal/Sail Rock to Kydaka Point S 13.26 20 7.54 0 0.00

05 March 1999 Seal/Sail Rock to Kydaka Point S 21.24 0 0.00 12 2.82

05 March 1999 Seal/Sail Rock to Kydaka Point S 15.25 1 0.33 14 4.59

05 March 1999 Seal/Sail Rock to Kydaka Point S 23.97 49 10.22 2 0.42

05 March 1999 Seal/Sail Rock to Kydaka Point S 15.19 6 1.97 1 0.33

05 March 1999 Seal/Sail Rock to Kydaka Point S 14.43 33 11.43 1 0.35

05 March 1999 Seal/Sail Rock to Kydaka Point S 22.60 29 6.42 0 0.00

05 March 1999 Seal/Sail Rock to Kydaka Point S 23.87 63 13.20 7 1.47

10 March 1999 Seal/Sail Rock to Kydaka Point S 13.00 44 16.92 1 0.38

10 March 1999 Seal/Sail Rock to Kydaka Point S 14.72 0 0.00 2 0.68

10 March 1999 Seal/Sail Rock to Kydaka Point S 15.29 0 0.00 1 0.33

10 March 1999 Seal/Sail Rock to Kydaka Point S 13.65 15 5.49 0 0.00

10 March 1999 Seal/Sail Rock to Kydaka Point S 25.13 14 2.79 0 0.00

10 March 1999 Seal/Sail Rock to Kydaka Point S 22.36 0 0.00 2 0.45

10 March 1999 Seal/Sail Rock to Kydaka Point S 20.66 1 0.24 0 0.00

10 March 1999 Seal/Sail Rock to Kydaka Point S 31.18 35 5.61 5 0.80

11 March 1999 Seal/Sail Rock to Kydaka Point S 13.32 69 25.90 2 0.75

11 March 1999 Seal/Sail Rock to Kydaka Point S 15.89 0 0.00 0 0.00

11 March 1999 Seal/Sail Rock to Kydaka Point S 13.99 58 20.73 0 0.00

17 March 1999 Seal/Sail Rock to Kydaka Point S 14.95 0 0.00 0 0.00

17 March 1999 Seal/Sail Rock to Kydaka Point S 14.64 3 1.02 0 0.00

17 March 1999 Seal/Sail Rock to Kydaka Point S 14.00 1 0.36 1 0.36

17 March 1999 Seal/Sail Rock to Kydaka Point S 13.23 5 1.89 0 0.00

18 March 1999 Seal/Sail Rock to Kydaka Point S 13.19 13 4.93 0 0.00

18 March 1999 Seal/Sail Rock to Kydaka Point S 14.40 0 0.00 0 0.00

18 March 1999 Seal/Sail Rock to Kydaka Point S 13.99 2 0.71 0 0.00

18 March 1999 Seal/Sail Rock to Kydaka Point S 23.26 67 14.40 2 0.43
Table 7a. Densities of Marbled Murrelets along the western Strait of Juan de Fuca between Seal and

Sail Rock and Kydaka Point in 1995 and 1996.

1995 1996

Distance

(m) of

transect

from

shore

Summer Winter1 Summer Winter2

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

200 3.56 ± 0.76

(4, 42.5)

2.04 ± 1.87

(2, 130)

9.96 ± 1.24

(2, 17.5)

2.68 ± 1.70

(2, 89.6)

7.31

(1, --)

5.97

(1, --)

17.52

(1, --)

--

500 2.75 ± 0.26

(2, 13.4)

3.76 ± 2.10

(2, 78.9)

3.38 ± 1.58

(2, 66.0)

2.79 ± 0.57

(2, 28.7)

1.30 ± 0.24

(2, 25.7)

5.48 ± 4.77

(2, 123)

3.47

(1, --)

--

800 1.23 ± 0.75

(2, 86.2)

0.50 ± 0.25

(3, 87.3)

0

(2, --)

0.94 ± 0.62

(2, 93.0)

1.18 ± 0.81

(2, 97.1)

1.21 ± 1.21

(2, 141)

0.24

(1, --)

--

1200 0.06 ± 0.06

(2, 141)

0

(1, --)

-- 0.32 ± 0.32

(2, 141)

0.53 ± 0.53

(2, 141)

-- 0.80

(1, --)

Zig-Zag -- -- -- 3.31 ± 2.00

(3, 104)

0.91 ± 0.52

(3, 99.5)

-- --

1

 Winter of 1995-1996

2

 Winter of 1996-1997 

Table 7b. Densities of Marbled Murrelets along the western Strait of Juan de Fuca between Seal and

Sail Rock and Kydaka Point in 1997 and 1998.

1997 1998

Distance

(m) of

transect

from

shore

Summer Winter1 Summer Winter2

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

200 147.7 ± 143.4

(3, 168)

8.41 ± 4.42

(5, 118)

5.10 ± 2.75

(3, 93.4)

3.15 ± 1.93

(5, 137)

39.0 ± 11.5

(5, 65.7)

29.6 ± 11.2

(5, 84.2)

1.15 ± 0.72

(6, 153)

1.11 ± 0.49

(5, 98.4)

500 1.70 ± 1.02

(4, 121)

0.69 ± 0.37

(4, 108)

4.83 ± 0.88

(4, 36.5)

8.70 ± 2.76

(4, 63.4)

7.26 ± 2.09

(9, 86.2)

5.80 ± 0.97

(5, 37.5)

0.28 ± 0.16

(6, 141)

0.36 ± 0.14

(4, 79.1)

800 0.35 ± 0.26

(5, 170)

0.20 ± 0.11

(4, 116)

2.08 ± 1.25

(4, 121)

0.57 ± 0.11

(3, 32.2)

1.51 ± 0.66

(5, 98.0)

0.58 ± 0.30

(3, 90.9)

0.18 ± 0.08

(6, 110)

0 ± 0

(3, --)

1200 -- -- -- -- 5.53

(1, --)

4.03

(1, --)

0.25 ± 0.12

(6, 122)

0.19 ± 0.19

(2, 141)

Zig-Zag 1.74 ±0.37

(3, 37.2)

1.15 ± 0.70

(5, 135)

3.69 ± 1.33

(4, 72)

4.15 ± 1.01

(4, 48.8)

8.28 ± 2.54

(7, 81.3)

6.68 ± 2.58

(4, 77.1)

0.94 ± 0.32

(5, 74.8)

0.60 ± 0.20

(3, 57.7)

1

 Winter of 1997-1998

2

 Winter of 1998-1999
Table 8a. Densities of Marbled Murrelets along the outer coast of Washington between Fuca Pillar

and Point of Arches in 1995 and 1996.

1995 1996

Distance

(m) of

transect

from

shore

Summer Winter1 Summer Winter2

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

400 3.64 ± 0.10

(2, 4.10)

2.20 ± 0.10

(2, 6.40)

-- -- -- -- -- --

700 -- -- -- -- -- -- -- --

1200 0

(2, --)

0

(2, --)

-- -- -- -- -- --

1

 Winter of 1995-1996

2

 Winter of 1996-1997 

Table 8b. Densities of Marbled Murrelets along the outer coast of Washington between Fuca Pillar

and Point of Arches in 1997 and 1998.

1997 1998

Distance

(m) of

transect

from

shore

Summer Winter1 Summer Winter2

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

AM

Mean ± SE

(n, cv)

PM

Mean ± SE

(n, cv)

400 0.96 ± 0.42

(5, 96.8)

2.57 ± 0.82

(5, 71.0)

3.93

(1, --)

-- 3.33 ± 0.95

(6, 70.2)

0

(1, --)

-- --

700 0.67 ± 0.23

(5, 78.6)

0.39 ± 0.05

(3, 21.9)

6.30 ± 1.12

(5, 39.8)

6.18 ± 0.73

(4, 23.8)

1.20 ± 0.01

(2, 1.20)

0.92 ± 0.57

(3, 107)

-- --

1200 0.71 ± 0.29

(4, 80.8)

0.40 ± 0.35

(5, 195)

4.76 ± 0.23

(4, 9.70)

4.94 ± 1.16

(6, 57.5)

0.52 ± 0.18

(2, 47.1 )

0.38 ± 0.38

(3, 173)

-- --

Zig-Zag 1.16 ± 0.43

(6, 90.4)

0.44 ± 0.32

(3, 124)

-- -- 0.65 ± 0.39

(4, 118)

-- -- --

1

 Winter of 1997-1998

2

 Winter of 1998-1999
Although these data may be used to address many issues including variation in murrelet density

in relation to year, season, time of day, distance from shore, and geographic location, the

immediate reason this research was funded was to complete two tasks: (1) to compare the mean,

variance, and coefficient of variation in zig-zag transects to those of each parallel transect

distance (e.g. 200m vs. 500m), and to recommend which type of transect (parallel or zig-zag) is

best for long-term monitoring of murrelets. 

Zig-zag transects have two advantages over parallel transects. First, as documented previously

(Thompson 1997a, 1997b), murrelets tend to occur in higher densities in morning versus

afternoon in summer (Tables 6 and 7, Figures 1 and 3); a similar but less pronounced pattern

exists in winter (Tables 6 and 7, Figures 2 and 4). Thus, differences between parallel transects

conducted at different distances from shore may be confounded by time-of-day effects unless

they are conducted at the same time of day. This is not an issue with zig-zag transects because

the temporal distribution of effort is the same across all distances from shore within the area

surveyed. Second, it is well known that murrelet density decreases with perpendicular distance

from shore (Thompson 1997a, 1997b); This is further documented here (Tables 6 and 7, Figures

1-5); however, the peak in this density is also known to vary among geographic locations, and,

more importantly, over time within and between seasons and years within geographic areas

(Tables 6 and 7, Figure 5). Thus, surveys conducted along a specific parallel transect may vary

over time due to changes in the overall density distribution of murrelets in relation to distance

from shore (e.g., a shift in the distance at which maximum density of muurelets occurs) rather

than to actual changes in total murrelet abundance. Because zig-zag transects sample a much

wider range of distances from shore, they are less likely to be affected by such changes in the

density distribution of murrelets in relation to distance from shore. These advantages aside,

comparison of coefficients of variation between zig-zag and parallel transects do not clearly

indicate that one kind of transect (i.e. zig-zag vs. parallel) is superior for maximizing statistical

power for detecting changes in population density. This issue is currently being discussed by the

ìPopulation Core Group,î a group of four biologists (myself, Steve Beissinger [University of

California at Berkeley], C.J. Ralph [U.S. Forest Service, Pacific Southwest Region], Marty

Rafael [U.S. Forest Service, Pacific Northwest Region]) and two statisticians (Tim Max and Jim

Baldwin) who are coordinated by the U.S. Fish and Wildlife Service; the charge of this group is

to develop a protocol for surveying for murrelets at sea, the data from which will be suitable for

monitoring population trends of murrelets at sea. Jim Baldwin and Steve Beissinger are currently

using empirical data to run simulation models to evaluate the relative strengths and weaknesses

of parallel versus zig-zag transects. We anticipate an answer from them this summer.

The second reason for conducting replicate sets of these various transects was to determine how

many replicates of a given transect should be done, on average, in a given area (e.g. outer coast

versus Strait of Juan de Fuca) and season (winter vs. summer) in order to achieve the statistical

power required to detect a change in density of murrelets of a given magnitude over a specified

time interval. As briefly explained above, the Population Core group has not yet decided how

transects should be oriented (e.g. zig-zag versus parallel), at what distance from shore they

should be placed, or how long they should be. Nor has any state or federal agency stated a

specific percent change in murrelet populations that they want to be able to detect over a given

number of years. As a result, I can not present a power analysis for a generally accepted
sampling scheme, because no such consensus currently exists. Instead, I present a preliminary

power analysis for the summer season for a subset of transect types and lengths that WDFW

conducted between 1995 and 1998. As mentioned above, transects along the Strait of Juan de

Fuca were conducted parallel to shore at 200, 500, 800, and 1200 meters, and in a zig-zag

orientation between 100 and 1300 meters from shore. Statistical power increases as the

coefficient of variation (CV) within each of the two or more samples being compared decreases. 

Thus, for the power analysis presented below, I chose the 500 m and 400 m parallel transects on

the Strait of Juan de Fuca and outer coast, respectively, to compare to zig-zag transects

conducted in the same location because these transects had lower CVs than other parallel

transects (see Table 9 below). Using values from Tables 7 and 8 above, I calculated the grand

mean murrelet density for each transect type and location, and the standard deviation of

individual means (rather than the mean of the standard deviations of the individual means)

included in the calculation of each grand mean; these values were as follows: 500m SJF: 3.59 ±

2.39, zig-zag SJF: 3.68 ± 3.10; 400m OC: 2.54 ± 1.05; zig-zag OC: 0.75 ± 0.37.

Table 9. Coefficients of variation of strip transects conducted along the western Strait of Juan de

Fuca and the northern outer Washington coast in 1995-1998 (years and time of day combined)

Season

Transect Type

Summer

mean (SD, n)

Winter

mean (SD, n) Location1

200m 101 (45.3, 6) 98.2 (47.1, 6) SJF

500m 74.2 (43.5, 8) 69.1 (40.0, 6) SJF

800m 111 (30.1, 8) 89.0 (19.8, 4) SJF

1200m 141 (0, 3) 132 (9.5, 2) SJF

Zig-Zag 89.0 (13.3, 6) 63.3 (12.2,4) SJF

400m 49.7 (41.9, 5) -- OC

700m 52.2 (49.0, 4) 31.8 (11.3, 2) OC

1000m 124 (71.1, 4) 33.6 (33.8, 2) OC

Zig-Zag 111 (18.1, 3) -- OC

1

 SJF = western Strait of Juan de Fuca; OC = northern outer Washington coast.

Based on these data, I did a calculated the power of detecting changes in population density

between two sampling periods (e.g. successive years) in 10% increments from 10% to 90% along

the western Strait of Juan de Fuca and the northern outer Washington coast using 5, 10, 15 and

20 replicates during each survey period. Along the western Strait of Juan de Fuca, 500 meter

transects parallel to shore have greater power for the same number of replicates than do zig-zag

transects (Figs. 6-7); interestingly, however, the opposite is true for the northern outer

Washington coast (Figs. 8-9).
Distance from shore of transect (m)

200 500 800 1200 Zig-Zag

Murrelets per km

2

0

10

20

30

40

50

60

70

80

90

n=13

n=17n=13 n=14 n=12

n=13

n=13

n=12 n=5 n=4

A.M.

P.M.

231 127 113 88 111 130 191 150104 136

Figure 1. Density of Marbled Murrelets along the western Strait of Juan de Fuca in summer 1995

through summer of 1998 in relation to distance from shore and time of day. Numbers below

sample sizes indicate coefficients of variation.
Distance from shore of transect (m)

200 500 800 1200 Zig-Zag

Murrelets per km

2

0

1

2

3

4

5

6

7

n=12

n=13

n=10

n=12

n=9

n=7

n=6

n=3

A.M.

P.M.

n=13

n=8

115 133 99 122 212 118 122 102 103 91

Figure 2. Density of Marbled Murrelets along the western Strait of Juan de Fuca in winter 1995

through winter of 1998 in relation to distance from shore and time of day. Numbers below

sample sizes indicate coefficients of variation.
Distance from shore of transect (m)

400 800 1200 Zig-Zag

Murrelets per km

2

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

n=12

n=7

n=8

n=6

n=10

n=8

n=10

n=3

82.3 76.0 61.1 105 102 200 97.9 124

A.M.

P.M.

Figure 3. Density of Marbled Murrelets along the northern outer coast of Washington in summer

1995 through summer of 1998 in relation to distance from shore and time of day. Numbers below

sample sizes indicate coefficients of variation.
Distance from shore of transect (m)

400 800 1200

Murrelets per km

2

0

1

2

3

4

5

6

7

8

n=1

n=4

n=4

n=6

n=0 39.8% 57.5% 23.8% 122%

n=5

A.M.

P.M.

Figure 4. Density of Marbled Murrelets along the northern outer coast of Washington in winter

1995 through winter of 1998 in relation to distance from shore and time of day. Numbers below

sample sizes indicate coefficients of variation.
Distance from shore of transect (m )

200 500 800 1200 Zig

M urrelets per km2

0

1 02 03 04 05 06 07 08 09 0

100

JuneJulyAugu

 57n=7

 252n=10

 59n=9

 66n=9

 80n=9

 93n=10

138n=4

 99n=12

122n=8

 22n=2

 --n=2

173n=3

 32n=5

 n

Figure 5. Density of Marbled Murrelets along the western Strait of Juan de Fuca in summer 1995 through summeto distance from shore and time of year. Numbers above sample sizes indicate coefficients of variation.
Reduction in Murrelet Density (%)

0 20 40 60 80 100

Power

0

20

40

60

80

100

5 transects

10 transects

15 transects

20 transects

Figure 6. Statistical power of detecting changes in murrelet density along the western Strait of

Juan de Fuca by conducting two sets of the same number of transects (5, 10, 15 or 20 replicates)

500 m parallel to shore as a function of the percent change in murrelet density and number of

replicates conducted in each set of transects.
Reduction in Murrelet Density (%)

0 20 40 60 80 100

Power

0

20

40

60

80

100

5 transects

10 transects

15 transects

20 transects

Figure 7. Statistical power of detecting changes in murrelet density along the western Strait of

Juan de Fuca by conducting two sets of the same number of zig-zag transects (5, 10, 15 or 20

replicates) as a function of the percent change in murrelet density and number of replicates

conducted in each set of transects.
Reduction in Murrelet Density (%)

0 20 40 60 80 100

Power

0

20

40

60

80

100

5 transects

10 transects

15 transects

20 transects

Figure 8. Statistical power of detecting changes in murrelet density along the northern outer coast

of Washington by conducting two sets of the same number of transects (5, 10, 15 or 20

replicates) 400 m parallel to shore as a function of the percent change in murrelet density and

number of replicates conducted in each set of transects.
Reduction in Murrelet Density (%)

0 20 40 60 80 100

Power

0

20

40

60

80

100

5 transects

10 transects

15 transects

20 transects

Figure 9. Statistical power of detecting changes in murrelet density along the northern outer coast

of Washington by conducting two sets of the same number of zig-zag transects (5, 10, 15 or 20

replicates) as a function of the percent change in murrelet density and number of replicates

conducted in each set of transects.
Task 2

We know from past research that numbers of seabirds, including murrelets, are tremendously

variable in time and space. This is unfortunate because their inherent variability makes detecting

meaningful changes in population levels of these birds very difficult, e.g., in the short-term

(within as much as a few years), apparent increases or decreases in population levels may simply

reflect variability in numbers of birds breeding, or migrating/dispersing, but not total numbers of

birds in a ìpopulation.î To detect real population changes, these birds must be monitored over

many years in order to measure within- and between-year variability in their numbers, and

thereby discriminate short-term fluctuations in apparent population numbers from long-term real

changes in population numbers. Thus, as indicated in Tables 1-4 (above), since my last report to

the TMTC, we have conducted an additional 3374 km of transects in winter and 7680 km of

transects in summer. Comparison of mean densities and variances of murres and murrelets from

the same transect areas within-season and among years gives us an estimate of interannual

variability in murre and murrelet densities within and among geographic areas (Figs. 1-4). 

Similarly, comparison of mean densities and variances of murres and murrelets from the same

transect areas between winter and summer among years gives us an estimate of seasonal

variability in murre and murrelet densities within and among geographic areas. Also,

comparison of mean densities and variances of murres and murrelets from the same transect

areas among months within the same season indicates the extent of within-season variation in

their densities. These data and results greatly improve our baseline knowledge of the distribution

and abundance of murrelets and other seabirds in Washington.

Task 3

The third task was designed to evaluate transect methodology that could improve our statistical

power. In 1995 and 1996 WDFW used ìstripî transects for collecting seabird abundance and

distribution data; in this method, all birds are counted within a ìstripî of 100 meters on each side

of our various research vessels. This method has two basic errors: (1) observers must be able to

accurate estimate the distance of 100 meters from the vessel in order to accurately determine

which birds are inside versus outside the ìstrip,î and (2) the detectability of birds in relation to

distance from the vessel differs among transects due to differences in observers, weather (sun,

glare, cloud cover, wind, rain), sea conditions (swell height and period, wind waves, etc.), and

platform (i.e., vessel height, size, etc.). 

An alternative transect method is the ìlineî transect (Buckland et al. 1993). This method is very

similar to the strip transect method, but differs in a few critical ways. In a line transect, like a

strip transect, birds are counted only within a specified distance on each side of a vessel;

however, in a line transect, the perpendicular distance to each bird from the vessel is also

estimated and recorded. By doing so, a detectability curve of the percentage of observations as a

function of distance from the boat may be generated. From this, one may empirically determine

the percentage of birds being missed on any given transect or set of transects. In turn, this may

be used to ìcorrectî transects to reflect the total number of birds that would have been seen if all

birds had been detected. By largely eliminating differences in the detectability between transects,

this method has the potential to vastly reduce variability in our data, thereby increasing our
statistical power. However, the accuracy of this method relies on two critical assumptions being

met: (1) all birds must be detected that are ìcloseî (i.e., within about 30 meters) to the transect

line of the boat, and (2) the boat must not cause birds to dive, fly or move away from the transect

line before being detected. If either of these assumptions are seriously violated, then subsequent

analyses of line transect data will yield erroneous results.

During the summer of 1998, we empirically measured (1) the percentage of murrelets on or near

the transect line that are not detected, for whatever reason, by standard observers, and (2) the

extent to which birds move away from the transect line. We did this by placing an extra

ìindependentî observer on the bow of our vessel who focused most of her effort on or near the

transect line. She searched for murrelets well in excess of 100 meters in front of the survey

vessel. Once seen, she estimated the angle of the bird off the transect line and its radial distance

from the vessel; perpendicular distance of the bird from the transect line is calculated as X =

r*sinθ where X = perpendicular distance, r = radial distance, and θ = angle from the transect line

(Fig. 10). She then followed the bird, noting all behaviors such as flying and diving, and noting

Figure 10. Diagrammatic representation of how line transect observations are made

the position of these behaviors, until it was seen by one of the standard observers. At that time,

she took a second set of radial distance and angle estimates. By comparing the perpendicular

distance of each murrelet when it was sighted initially by our independent observer to its distance

when sighted subsequently by a standard observer, the perpendicular distance that it moved

toward or away from the transect line was calculated. If a murrelet was not seen by a standard

observer, but was still visible within the transect area (100 radius of the boat), itís position was

noted when it was directly abeam of the vessel. If a murrelet was not seen by a standard observer

because it dove or flew away, the position at which it dove or flew away was noted by the

independent observer.

Results
Percentage of birds not detected by standard observers. This study was designed to allow us to

answer a large suite of questions. As a result, the entire data analysis is rather long and complex

and are in the process of be prepared as a manuscript for publication (published abstracts of our

results will appear in Pacific Seabirds volume 26). However, for the TMTC, we addressed two

specific questions: (1) what percentage of murrelets are not detected by standard observers as a

function of perpendicular distance from the transect line?, and (2) of murrelets that are detected

by standard observers, how far do they move perpendicularly toward or away from the transect

line before being detected?

The percentage of murrelets that were not detected by standard observers as a function of

perpendicular distance from the transect line is summarized in Table 10 and Figures 11 and 12

below.
Table 10. Percentage of murrelets that were not detected by standard observers as a function of

perpendicular distance from the transect line.

Perpendicular Birds that Birds that Birds that Total Percent Percent Percent

Distance (m) dove and flew and did not fly Total birds missed missed missed Total Percent

from transect were were or dive and birds not from from that did not percent of birds

line missed missed were missed missed missed diving flying fly or dive missed detected

0-10 5 0 3 8 70 6.41 0.00 3.85 10.26 89.74 

11-20 9 0 3 12 67 11.39 0.00 3.80 15.19 84.81 

21-30 3 0 0 3 48 5.88 0.00 0.00 5.88 94.12 

31-40 4 0 2 6 58 6.25 0.00 3.13 9.38 90.63 

41-50 1 0 1 2 21 4.35 0.00 4.35 8.70 91.30 

51-60 2 0 1 3 19 9.09 0.00 4.55 13.64 86.36 

61-70 1 0 3 4 11 6.67 0.00 20.00 26.67 73.33 

71-80 0 0 0 0 6 0.00 0.00 0.00 0.00 100.00 

81-90 1 0 0 1 3 25.00 0.00 0.00 25.00 75.00 

91-100 0 0 0 0 2 0.00 0.00 0.00 0.00 100.00 

In collaboration with Tom Hamer (Hamer Environmental, Mt. Vernon, WA), Jeff Laake

(National Marine Mammal Lab, NOAA), and Kirsten Brennan (College of Forestry Resources,

University of Washington), we used DISTANCE software to estimate the density of murrelets

based on the independent observers data (i.e., of murrelets observed presumably before they were

disturbed by one of our oncoming survey vessels). We refer to this as the unbiased model

meaning that the data are presumably unbiased by any movement by the murrelets caused by

disturbance due to our survey vessels. We compared these density estimates to those obtained

using the standard observers data (i.e., of murrelets observed presumably after they may have

been disturbed by one of our oncoming survey vessels). We refer to this as the biased model

meaning that the data may be biased by movement by murrelets away from the transect line in

response to oncoming survey vessels. This comparison indicated that densities differed little (10-

20%) between these models depending on how parameters were chosen for the DISTANCE

software, suggesting that the combination of missed birds and movement of birds does not

constitute a large error relative to the magnitude of natural variation in the distribution and

abundance of murrelets.

Distance moved toward or away from the transect line by murrelets prior to detection by

standard observers. Overall, murrelets do not appear to react strongly to the oncoming approach

of survey vessels. Murrelets were initially spotted by the independent observer at 154.4 ± 2.3 m

(mean ± SE), and subsequently observed by standard observers at 59.4 ± 1.7 m in front of the

vessels. During this interval, murrelets moved, on average, 3.8 ± 1.2 m away from the transect

line. However, murrelets closest to the transect line moved away from the transect line a greater

absolute distance, and at a greater rate than murrelets further from the transect line (Figures 13

and 14). For example, murrelets within 40m and 20m of the transect line moved 7.3 ± 0.8 m,

and 9.7 ± 1.1 m away from the transect line, respectively. We have no explanation for the

apparent approach toward the transect line of murrelets initially seen at distances greater than 50

meters perpendicular to the transect line. The most likely explanation is that it reflect a

systematic bias in the way the independent observer estimated radial angles and distances of
murrelets from the transect line and survey vessel, respectively. However, we tested the

independent observer for such biases (Figures 15 and 16), and corrected the raw data to reflect

her biases thereby removing most to all bias introduced to the data by her biased data collection.

Discussion

Percentage of birds not detected by standard observers. Overall, these data indicate that 12.7%

of murrelets were missed between 0 and 20 meters of the transect line, and 10.7% were missed

between 0 and 40 meters of the transect line. As a result, g(0) is significantly less than one,

thereby potentially seriously violating one of the basic assumptions of line transect methodology

and the DISTANCE software used to analyze such data. The USFWS Population Core group is

currently discussing how to deal with this problem. There are two alternatives: (1) ignore the

problem and live with the error, or (2) determine and implement a mechanism for estimating a

correction factor to reduce the magnitude of the error. The second alternative could be achieved,

theoretically, by placing an independent observer on each survey vessel each season for a period

of time sufficient to estimate the percentage of birds missed on each vessel. The concern is that

this might introduce more error than it corrects for. This was discussed at a meeting of the

Population Core Group in mid-May; the consensus was that an independent observer will

probably be employed in the summer of 2000 to begin research into the feasibility of using

independent observers to estimate percentages of undetected murrelets by various marine

murrelet survey crews.

Distance moved away from the transect line by murrelets prior to detection by standard

observers. At all distances away from the transect line (e.g., 0-10m, 11-20m, etc.), murrelets

moved less than 10 meters away from the transect line, on average, between the time they were

were initially spotted by the independent observer and subsequently observed by standard

observers. This result is similar to the results of our pilot study in 1997 in which we found that

murrelets moved an average of 9.6 ± 1.5m (mean ± SE) away from the transect line (Hamer and

Thompson 1997). Calculation of murrelet densities based on data from the biased and unbiased

models (described above) indicated that biased data would underestimate unbiased data by about

10-20% depending on values we chose for various parameter inputs into the DISTANCE

program (Buckland et al. 1993, Laake et al. 1996) and the perpendicular distance from the

transect line at which the data were truncated. Relative to the magnitude of errors introduced

into the data from many other sources (e.g. variability among observers and weather conditions

such as glare, beaufort magnitude, swell height), it is my opinion, and that of other experts on the

subject (e.g., Jeff Laake) that this is not an effect worth trying to control or correct for.
Perpendicular Distance from Transect Line (m)

0-20 21-40 41-60 61-80 81-100

Murrelets Observed by Standard Observers (%)

0

20

40

60

80

100

Figure 11. Percentage of murrelets detected by standard observers in relation their perpendicular

distance from the transect line.
Perpendicular Distance from Transect Line (m)

0-20 21-40 41-60 61-80 81-100

Murrelets Missed by Standard Observers (%)

0

5

10

15

20

Did not dive

Dove

Figure 12. Percentage of murrelets that were not detected by standard observers as a function of

murrelet behavior and perpendicular distance from the transect line.
Perpendicular Distance from Transect Line (m)

0-10 21-30 41-50 61-70 81-90

Perpendicular Distance Moved Away from Transect Line (m)

-50

-40

-30

-20

-10

0

10

Figure 13. Absolute distance moved perpendicularly away from the transect line by murrelets

between their initial sighting by the independent observer and their subsequent sighting by

standard observers.
Perpendicular Distance from Transect Line (m)

0-10 21-30 41-50 61-70 81-90

Rate of Perpendicular Distance Moved Away from Transect Line (m/10m longitudinal) 

-6

-5

-4

-3

-2

-1

0

1

2

3

Figure 14. Rate of movement perpendicularly away from the transect line by murrelets between

their initial sighting by the independent observer and their subsequent sighting by standard

observers.
Actual Angle from Transect Line (degrees)

0 10 20 30 40 50 60 70 80 90

Estimated Angle from Transect Line (degrees)

0

10

20

30

40

50

60

70

80

90

Y = 0.868X + 1.50

R2 = 0.896

Figure 15. Linear regression of the independent observerís estimated angle from the transect line

to buoys (simulating murrelets) on actual angles buoys measured using digital compasses.
Actual Radial Distance from Transect Line (m)

0 50 100 150 200 250 300

Estimated Radial Distance from Transect Line (m)

0

50

100

150

200

250

300

Y = 0.938 + 5.26

R2 = 0.977

Figure 16. Linear regression of the independent observerís estimated radial distance from the

survey vessel to buoys (simulating murrelets) on actual distance to buoys.
Objective 2: Surveys of potential murre breeding colonies.

Historically, murres are known to have bred on many rocks and islands along the outer

Washington coast south of Tatoosh Island (Speich and Wahl 1989). However, in the last decade

or so, Tatoosh Island is the only colony at which murres are well documented to currently breed

annually. Ulrich Wilson (USFWS, unpubl. data) has observed chicks recently on various other

colonies (e.g., Huntington Island in mid-June 1995) on which murres are known to have bred

previously. These data clearly indicate that murres are breeding in at least small numbers at

some other locations in Washington and, in at least some of these colonies, may be doing so

earlier than on Tatoosh Island, i.e., the timing of their breeding may be closer to that of Oregon

than Washington murre colonies. As a result, better documentation, and estimates of numbers, of

breeding pairs of murres at potential Washington Murre colonies other than Tatoosh Island are

necessary. In addition, individual murre breeding colonies vary tremendously in their phenology

as well as their relative attendance and reproductive success. This variation presumably reflects

both local and regional differences among colonies, especially with regard to prey availability. 

With regard to the breeding of murres at colonies in Washington other than Tatoosh Island, it is

unclear whether they tend to more closely follow the phenology of Oregon or Washington

colonies (i.e. Tatoosh Island). As a result, the objective of this study was to complete two

specific tasks: 

(1) Conduct land-based surveys of the Grenville complex (Erin, Erinís Bride, Grenville Arch and

Big Stack) for possible breeding activity.

(2) If murres are breeding at the Grenville complex, determine whether their breeding phenology

is closer to that of Oregon colonies versus Tatoosh Island for the same season.

Tasks 1 and 2

Every one to seven days between 10 July - 7 August, 1997, and 2 July - 29 July 1998, we used a

Questar telescope to observe the Grenville complex from the old naval base on the Quinault

Indian Nation for potential murre attendance and breeding activity (Table 11). The structure of

the Grenville Complex rocks is such that very little of the suitable habitat available to murres is

visible from this observation point; most of the available nesting area is on the west side of these

rocks that is not visible from the old naval base. As a result, aerial surveys conducted by Ulrich

Wilson (USFWS) and others (e.g. Steve Jeffries, WDFW) have yielded counts in the thousands

in recent years. However, the main objective of this study was not to obtain absolute numbers of

murres attending and/or breeding on these rocks, but rather to determine whether they were

attempting to breed and successfully rearing young. Although it is rarely possible to identify

chicks from airplanes during aerial surveys, land-based observations are clearly superior for

monitoring potential reproductive activity. 

In general, attendance was lowest early in the morning and greatest at the end of the day;

attendance typically increased to an initial maximum by 1030 h, subsequently decreased until

1230 h, and then increased again to a daily maximum at about 1730 h. As indicated in Table 11,

eggs were first observed in early July and last seen on 5 August; in addition, chicks were first

observed on 22 July, and first fledged about 5 August. This phenology is essentially identical to

that of Tatoosh Island (J. Parrish, unpubl. data). In contrast, murres at Oregon colonies typically
begin egg-laying in late April to early May, and fledge young by late June to early July (J. Parrish

unpubl. data).

Table 11. Locations and maximum daily numbers of Common Murre adults, chicks and eggs at

the Grenville Complex in the summers of 1997 and 1998.

Location

Date

Big Stack

(adults, eggs, chicks)

Erin

(adults, eggs, chicks)

Erinís Bride

(adults, eggs, chicks)

Grenville Arch

(adults, eggs, chicks)

10 July 1997 46, 2*, 0 -- -- --

14 July 1997 106, 0, 0 -- -- --

21 July 1997 103, 0, 0 -- -- --

22 July 1997 102, 0, 1 -- -- --

23 July 1997 105, 0, 2-4(?) -- -- --

28 July 1997 71, 0, 9 -- -- --

1 August 1997 52, 1, 3 -- -- --

5 August 1997 90, 1, 1 -- -- --

7 August 1997 115, 1, 2 -- -- --

2 July 1998 91, 0, 0 19, 0, 0 24, 0, 0 35, 0, 0

8 July 1998 68, 0, 0 51, 0, 0 13, 0, 0 0, 0, 0

15 July 1998 47, 0, 0 10-15, 0, 0 0, 0, 0 40-50, 0, 0

21 July 1998 57, 0, 0 20, 0, 0 1, 0, 0 3, 0, 0

29 July 1998 40, 0, 0 29, 0, 0 3, 0, 0 24, 0, 0

* Two eggs initially observed about 1 July by Ken Warheit (WDFW) and subsequently on about

5 July by C. Thompson (WDFW).

Objective 3: Immigration of murres from Oregon.

Murres breed in huge numbers (approximately 700,000 total murres in Oregon, R. Lowe,

USFWS, Pers. comm.) in Oregon compared to Washington where only a few thousand pairs

breed. Thus, when murre mortality results from natural or anthropogenic events, it is a goal of

management to be able to estimate as best as possible the percentage of mortality to Oregon

versus Washington murres. Documenting the magnitude and geographic extent of summer and

fall immigration of post-reproductive adult murres and their chicks from Oregon breeding

colonies northward into Washington is a first step toward this goal. 
Murres fledge with their fathers from breeding colonies in Oregon in late June or early July, on

average, and disperse as far north as Cape Flattery and the outer Strait of Juan de Fuca by late

July to early August (Thompson 1997a). In contrast, young murres do not fledge from Tatoosh

Island, the only colony at which murres are known to breed annually in Washington, until early

August or later. As a result, the distribution and abundance pattern of murres in Washington

changes over the course of the summer. Murre chicks are accompanied by their fathers for at

least a month after fledging. Thus, we speculated that the most definitive and least costly way to

monitor the immigration of post-reproductive Oregon murres into Washington is by documenting

the distribution and abundance of dad-chick murre pairs along the outer coast of Washington

from late June through late August or early September.

We attempted to do this in summer 1996; however, extremely low reproductive success of

Oregon murres resulted in very low rates of dad-chick pair immigration into Washington in July

and August (Thompson 1997a). Thus, in the summers of 1997 and 1998, we surveyed the outer

Washington coast for dad-chick pairs every other week from early June through early to midSeptember (Tables 2, 4, 12).

Table 12. Observations of dad-chick pairs of murres along the outer Washington coast and Strait

of Juan de Fuca in summer 1997. 

Date

General

Geographic 

Location Transect Location

Distance

from

shore

Transect

Length

(km)

Number

of dad/

chick

pairs

Density

per 10

linear

kilometer

06 AUG North Coast Lapush to Neah Bay offshore* 80.25 4 0.25

06 AUG North Coast Neah Bay to Lapush nearshore** 80.11 5 0.31

13 AUG North Coast Umatilla to Lapush offshore 133.56 7 0.26

13 AUG North Coast Westport to Lapush nearshore 161.06 14 0.43

14 AUG North Coast Lapush to Westport offshore 124.66 21 0.84

05 AUG Strait Port Angeles- Neah Bay nearshore 102.41 0 0.00

07 AUG Strait Neah Bay to Port Angeles offshore 97.95 1 0.05

19 AUG Strait Port Angeles east 15 km 200 M 14.63 0 0.00

19 AUG Strait Port Angeles to Neah Bay offshore 97.08 1 0.05

19 AUG Strait Seal Rock to Kydaka Point 500 M 15.52 0 0.00

19 AUG Strait Seal Rock to Kydaka Point zig-zag 18.97 0 0.00

19 AUG Strait Seal Rock to Kydaka Point 800 M 14.67 0 0.00

20 AUG Strait Seal Rock to Kydaka Point 500 M 14.99 0 0.00

20 AUG Strait Seal Rock to Kydaka Point zig-zag 20.69 1 0.24

20 AUG Strait Neah Bay to Port Angeles nearshore 102.9 4 0.19

25 AUG Strait Seal Rock to Kydaka Point 200 M 14.88 2 0.67

25 AUG Strait Seal Rock to Kydaka Point 500 M 14.17 0 0.00

25 AUG Strait Seal Rock to Kydaka Point 200 M 14.99 0 0.00

25 AUG Strait Seal Rock to Kydaka Point 800 M 13.73 1 0.36

25 AUG Strait Seal Rock to Kydaka Point 800 M 13.9 1 0.36

25 AUG Strait Seal Rock to Kydaka Point zig-zag 20.6 1 0.24

16 JUL South Coast Willapa Bay to Columbia River nearshore 76.34 0 0.00

16 JUL South Coast Mouth of Willapa Bay 6.49 0 0.00
17 JUL South Coast Willapa Bay to Columbia River nearshore 75.48 1 0.07

30 JULY South Coast Willapa Bay to Columbia River nearshore 80.88 3 0.19

30 JULY South Coast Willapa Bay to Columbia River offshore 81.09 7 0.43

31 JULY South Coast Willapa Bay to Columbia River offshore 82.91 11 0.66

31 JULY South Coast Willapa Bay to Columbia River nearshore 77.06 4 0.26

12 AUG South Coast Willapa Bay to Columbia River nearshore 76.79 14 0.91

12 AUG South Coast Columbia River to Willapa Bay offshore 77.03 19 1.23

12 AUG South Coast Mouth of Gray's Harbor 4.26 0 0.00

14 AUG South Coast Mouth of Gray's Harbor 8.15 1 0.61

* "nearshore" approximates 400 meters from shore, except in locations where hazards exist.

** "offshore" approximates 1200 meters from shore

No dad/chick pairs found during surveys of SOUTH COAST (south of Gray’s Harbor) on 19-20 June

and 02 July

No dad/chick pairs found during surveys of NORTH COAST (north of Gray’s Harbor) on 11-12 June,

24-25 June, 9-10 July, and 15 July

No dad/chick pairs found during surveys of STRAITS on 22-25 July

Figures 17 and 18 (below) illustrate the density of dad-chick pairs of murres immigrating

northward along the outer coast of Washington and eastward down the Strait of Juan de Fuca in

the summers of 1997 and 1998. Based on data from other researchers who observed the breeding

of murres at Oregon colonies in 1997 and 1998 (Roy Lowe, USFWS; J. Parrish, Univ. Of

Washington), we know that murres achieved much greater reproductive success in 1998 than in

1997. Correspondingly, the mean density of dad-chick pairs in 1998 was about seven times that

of 1997. This suggests that this method of monitoring murre immigration is both sensitive and

accurate, and may be used in future years to forecast the magnitude of murre immigration into the

Strait of Juan de Fuca and Puget Sound during Tribal and non-tribal gill-net fisheries.
Common Murres

 (summer 1997)

Date

1 July 1 Aug 1 Sept

Parent-chick pairs per 10 linear km

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

Southern Coast

Strait of Juan de Fuca

Northern Coast

Figure 17. Density of dad-chick pairs of Common Murres along the outer coast and Strait of Juan

de Fuca of Washington in the summer of 1997.
Date

June 1 July 1 August 1 Sept. 1

Murre Chicks per 10 linear Km

0

2

4

6

8

10

12

South Coast

North Coast

Straits

Figure 18. Density of dad-chick pairs of Common Murres along the outer coast and Strait of Juan

de Fuca of Washington in the summer of 1998.
Literature Cited

Buckland, S.T., D.R. Anderson, K.P. Burnham, and J.L. Laake. 1993. Distance sampling:

Estimating abundance of biological populations. Chapman and Hall, London.

Laake, J.L., S.T. Buckland, D.R. Anderson, and K.P. Burnham. 1996. Distance userís guide,

Volume 2.2. Colorado Cooperative Fish and Wildlife Research Unit, Colorado State

University, Fort Collins, CO.

Hamer, T., and C.W. Thompson. 1997. Avoidance of boats by Marbled Murrelets during marine

surveys. Final Report to U.S. Fish and Wildlife Service, North Pacific Coast Ecoregion,

Olympia, WA. 17 pp.

Speich, S.M., and T.R. Wahl. 1989. Catalog of Washington seabird colonies. U.S. Fish and

Wildlife Service Biological Report 88(6). 510 pp.

Thompson, C.W. 1997a. Distribution and abundance of Marbled Murrelets and Common Murres

on the outer coast of Washington ó Completion report to the Tenyo Maru Trusteeís

Council. Washington Dept. of Fish and Wildlife, Olympia, WA.

Thompson, C.W. 1997b. Distribution and aundance of Marbled Murrelets on the outer coast of

Washington, winter 1996-1997. Draft report to the Washington Department of Natural

Resources.