North American Birds

VOLUME 69 NO3 2016

A Quarterly Journal of Ornithological Record Published by the American Birding Association. The mission of the journal is to provide a complete overview of the changing panorama of our continent’s birdlife.

Issue link: http://nab.aba.org/i/778845

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334 N O R T H A M E R I C A N B I R D S P E L A G I C B I R D S F R O M C R U I S E S H I P S A LO N G T H E PA C I F I C C O A S T Gulls occur between late fall and early spring (e.g., 250 between Tillamook and Curry, OR 10 Nov 2015, and see above). Off British Co - lumbia, this species is most numerous in fall but most widespread offshore during winter and spring, and it has been recorded up to 740 (spring) and 980 (winter) km offshore (Kenyon et al. 2009). THAYER'S GULL (Larus thayeri) Very uncommon migrant and winter visitor offshore, out to the shelf edge, ca. 55-80 km offshore, rare out to 90 km. The species oc - curs most regularly south to Oregon waters. Few were seen in spring by the time the cruis - es occur. The latest was a first-cycle bird off Coos, OR 10 May 2012. Larger counts occur offshore during late fall and winter, e.g., 6 between Tillamook and Curry, OR 10 Nov 2015, 9 between Lane, OR and Grays Harbor, WA 2 Dec 2015. GLAUCOUS-WINGED GULL (Larus glaucescens) In northern waters adjacent to breeding sites, uncommon to fairly common to the edge of the shelf, ca. 45-90 km offshore; rare out to 100 km, and Briggs et al. (1987) noted individuals at 150+ km. Kenyon et al. (2009) noted that this species was found during at-sea surveys km. A cruise-day off Oregon only 35–60 km offshore produced 475 birds (400 of which associated with a fleet of trawlers ca. 37 km off southern Curry) on 20 May 2016. Briggs et al. (1987) found scattered birds out to 95 km and noted that numbers well offshore were at a minimum during the nesting season, April–August. Yet, one of the high cruise-ship counts of 130 birds from well off central Cali - fornia was made 10 May 2013. CALIFORNIA GULL (Larus californicus) Fairly common migrant and winter visitor, uncommon in summer, to the shelf edge 55- 80 km offshore; rare out to 95 km. This is often the dominant Larus gull offshore near the shelf edge, including in winter, Octo - ber–March. Off British Columbia, maximum counts are typically made over the shelf from July or August through October (Kenyon et al. 2009). Briggs et al. (1987) found the spe - cies most numerous within 50 km of shore, but with some birds out as far as ca. 160 km off the mainland in southern California. High cruise-ship counts in spring, by month, were 400 between Santa Barbara and Monterey, CA 15 Apr 2013 and 140 off Santa Barbara to San Francisco, CA 10 May 2013. Small numbers of presumed non-breeders may be found off - shore through the summer. A juvenile had arrived 16 Jul 2014 ca. 53 km off Curry, OR. The largest offshore counts of California Gulls typically occur between fall and early spring (e.g., 400 between Tillamook and Cur - ry, OR 10 Nov 2015, and see above). HERRING GULL (Larus argentatus) Most numerous off Alaska and northern British Columbia. Farther south, it is an un - common to occasionally fairly common mi- grant and visitor offshore to the shelf edge, ca. 55-90 km offshore; uncommon to rare to 100 km out; 1 bird was 170 km west of Cape Blanco, Curry, OR 12 May 2016. High counts south to Oregon included a total of 60 off Oregon and Washington 21 Mar 2015. Off California, most maxima in spring were under 15 individuals, with highs of 18 seen between Santa Barbara and San Fran - cisco 16 Apr 2012 and 20 between Monterey and Mendocino 20 Mar 2015. South of British Columbia, small numbers (including a few adults) lingered through early and mid-May; the latest was 22 May 2014 ca. 69 km off Del Norte, CA. In early summer, 1 was 61 km off Curry, OR 8 Jun 2013. The largest offshore counts of Herring 655 there 21 May 2014; 730 off Curry to Til- lamook, OR 29 Apr 2015; 1000 off Califor- nia, Oregon, and Washington 6-8 May 2015; a huge concentration of 3000 birds 39 km off Estevan Point, Vancouver Island (49.37° N, 127.11° W) 19 May 2015; and 900 off Clallam, WA 19 May 2016. A few may linger through early June. Small numbers seen be - tween mid-June and mid-July may have been summering non-breeders or early returning failed breeders: e.g., 24 between Douglas, OR and Humboldt 18 Jul 2013, and 10 off Del Norte and Humboldt 16 Jul 2014; 35 had ar - rived off Marin and Sonoma, CA 29 Jul 2013, as had 8 birds in those same waters 31 Jul 2015. A very early juvenile was at Cordell Bank, Sonoma 31 Jul 2015. Later in fall, Sabine's Gulls are uncommon to very common, peaking between late Au - gust and mid-September or early October (Ainley 1976, Roberson 2002, Wahl et al. 2005, Herlyn and Contreras 2009). Cruise maxima included 1750+ between 75-100 km off Oregon (1480 of which off Lincoln) 17 Sep 2007; a total of 3294 birds 70-100 km off Oregon (with 1516 off Lincoln and 1091 off Lane) 22 Sep 2009 (also a record date for Long-tailed Jaegers and Arctic Terns); 800+ off mouth of Strait of Juan de Fuca 5 Sep 2013; and 800+ off central and southern Van - couver Island 11 Sep 2015. Small numbers occurred regularly south of British Columbia through late October, e.g., 26 Oct 2012 ca. 67 km off Monterey, CA. BONAPARTE'S GULL (Chroicocephalus philadelphia) Uncommon spring migrant in small flocks out to at least 70 km offshore, more rarely to 90 km. Most birds are found only over in - shore waters. Briggs et al. (1987) noted this species up to only 40 km from the mainland or islands. The high cruise count was of a total of 50 birds 82-93 km off Oregon and Washington 21 Mar 2015. This species was also recorded during fall migration as singles and small flocks well off - shore—out to 90 km—with the earliest birds south of British Columbia being 4 off Lane, OR 22 Sep 2009, and occurring until at least early December (e.g., 9 birds 57-82 km off Monterey to Marin, CA 1 Dec 2015). Bonapar - te's Gull winters in numbers off southern California out to 40 km (Briggs et al. 1987). WESTERN GULL (Larus occidentalis) Uncommon to fairly common to the shelf edge, ca. 55-80 km offshore; rare out to 90 Figure 16. Certainly one of the most startling discoveries made by the San Francisco to southeastern Alaska round- trip Princess cruises during late spring has been the thou- sands of molting Short-tailed Shearwaters found among the even larger numbers of molting Sooty Shearwaters in Hecate Strait, east of Haida Gwaii, British Columbia. This concentration is unique in the northeast Pacific Ocean south of Aleutian waters. This individual Short-tailed was photographed just on the west side of Haida Gwaii 13 May 2016. Photograph by Bruce Rideout.

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