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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336 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 PARASITIC JAEGER (Stercorarius parasiticus) The first spring migrants typically arrive be - ginning in early April off Oregon (Gilligan et al. 1994) and in late April off Washington (Wahl et al. 2005). Although Parasitic Jaeger is considered primarily an inshore species, migrants were encountered in small num - bers (single digits per day) well offshore out to 80 km and even over deep water beyond the shelf edge, e.g., 1 bird 370 km off south - ern Vancouver Island 9 May 2011; 11 adults heading north ca. 90 km off both Oregon and Washington 21 May 2014; 3 birds 140-200 km off Curry and Coos, OR 13 May 2015; 10 birds 129-225 km off Del Norte, CA to Doug - las, OR 12 May 2016; and single birds 214 km off Brooks Peninsula, Vancouver Island, and 150 km south of southern end Haida Gwaii 13 May 2016. The high one-day count, by far, was of 37 birds 45-80 km off Lincoln, OR to Mendocino, CA (18 in Oregon, 19 in California) 21 May 2015. A few individuals were still passing northward in early June, and a very few presumed non-breeders were seen in June and early July. The first southbound migrants (mostly failed breeders?) appear by mid-July, and als recorded during at-sea surveys off British Columbia were between early May and early October (Kenyon et al. 2009). Most cruise maxima in spring were only of up to 20 birds/ day, with a few up to 40 birds/day, and higher totals of 44 off Humboldt and Del Norte, CA (and 55 between Humboldt and Lincoln, OR) 30 Apr 2014 and an early high of 58 between Monterey, CA and Grays Harbor, WA 20-21 Mar 2015. A few individuals were still passing northward in early June, and a few presumed non-breeders were seen in June and early July. The first southbound migrants (mostly failed breeders?) appear by mid-July, and small numbers (mostly single digits) were seen regularly by the end of the month. In most regions, this species, like the other two jaegers, is more numerous in fall than in spring (Briggs et al. 1987, Roberson 2002, Wahl et al. 2005). Fall maxima from cruise ships were unimpressive, however, and included just 63 off Curry, OR 29 Sep 2008 and 85 off Or - egon 22 Sep 2009. Late-season highs—cor- responding with the latest cruises—were 23 birds between Monterey and Mendocino, CA 1 Dec 2015, 19 between Clatsop and Coos, OR 16 Dec 2015, and 21 between Marin and San Luis Obispo, CA 17 Dec 2015. Island (57.85° N, 136.70° W) 18 Sep 2011 and another was 37 km west of Forrester Is - land (54.78° N, 134.12° W) 6 Aug 2015. In fall, this species is found regularly in small numbers, peaking between late August and mid-October (Wahl 1975, Ainley 1976, Kenyon et al. 2009), with smaller numbers through late October or even later off Califor - nia (Briggs et al. 1987). Some 3-8 individu- als was the typical total per two-day autumn cruise spent offshore, with larger counts of 15 off Oregon 22 Sep 2009, 9 between Humboldt and San Mateo, CA 27 Sep 2011, 8 between southern Haida Gwaii and central Vancouver Island 4 Sep 2013 and 12 there 6 Sep 2015, 10 off Oregon 24 Sep 2013, 12 between Coos, OR and Sonoma, CA 15-16 Sep 2015, and 11 between Lincoln and Curry 28 Sep 2015. The latest were 2 birds 67 km off Monterey, CA 26 Oct 2012. POMARINE JAEGER (Stercorarius pomarinus) Migrants are concentrated over waters sea- ward of the continental shelf, though rela- tively few birds are recorded well beyond 100 km offshore (Briggs et al. 1987). North of the species' regular winter range, most individu - Figure 18. One of the more common species seen over the continental shelf and near the shelf edge is Fork-tailed Storm-Petrel. This species is especially numerous off northern British Columbia and southeastern Alaska, where single-day cruise-ship totals have reached 10,000 birds. This individual was photographed crossing under the bow off British Columbia on 9 July 2014. Photograph by Martin Meyers.

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