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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337 V O L U M E 6 9 ( 2 0 1 6 ) • N U M B E R S 3 / 4 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 there was a small but regular occurrence of transient individuals up to 100-110 km from land between Vancouver Island and Haida Gwaii. In addition, 2 were 28 km off cen - tral Vancouver Island 20 May 2014. Farther south, the species is rare well offshore, with records of apparent northbound migrants off Washington in August and September (Wahl et al. 2005). Off Oregon and Washington, a total of 16 presumed southbound spring mi - grants (from inshore Washington/British Co- lumbia wintering grounds) were well off the coast 21 Mar 2015, including 3 birds each ca. 92 km off Tillamook, 92 km off Clatsop, and 81 km off Grays Harbor. Off California, small numbers were seen on several oc - casions out to the vicinity of Cordell Bank Marin/Sonoma, some 37 km offshore. MARBLED MURRELET (Brachyramphus marmoratus) Uncommon resident of inshore waters within 2 km of land. Rare farther offshore, although 20+ birds have been observed in flight as far as ca. 100 km in the northern Gulf of Alaska during both late May and mid-August (pers. obs.), perhaps performing cross-Gulf post- breeding dispersal. Farther south, 3 were 30- 35 km off central Vancouver Island 19 May 2015. Kenyon et al. (2009) noted a small number of birds to 85-100 km off Vancouver Island and southern Haida Gwaii during sev - eral seasons. SCRIPPS'S MURRELET (Synthliboramphus scrippsi) Often found in twos that likely involve pairs. Fairly common off southern California in spring, uncommon at that season north to San Luis Obispo and rare but regular north to at least Monterey and probably to San Mateo (where small numbers of birds have been seen in early and mid-May). Briggs et al. (1987) reported that—following nest - ing—adults and adults with young begin dispersing northward and farther offshore in May, mostly 20-100 km offshore, north to Monterey in late spring, rarely in numbers by June off San Francisco, and with peak dis - persal occurring August–October. Karnovsky et al. (2005) noted that such post-breeding dispersal brings the largest concentration of birds to between Point Conception and Cape Mendocino, CA, moderate densities as far as central Oregon, and low densities off Wash - ington and southern and central British Co- lumbia. Perhaps early for northern California were duos off Mendocino 16 May 2012; 59 km off Humboldt (40.50° N, 125.11° W) 24 May 70-100 km off Oregon (with 182 off Tilla - mook) 22 Sep 2009 (also a record date for Sabine's Gulls and Arctic Terns); and 180 be - tween Clatsop, OR and San Mateo CA 15-16 Sep 2015. Small numbers continue through much of October, through early October off British Columbia (Kenyon et al. 2009). In some years, larger numbers of young birds can be found well offshore into the second half of October; e.g., a non-cruise record of ca. 500 juvenile and subadult Long-tailed Jaegers 92-212 km off northern California and southern Oregon 19-21 October 2005 (Pyle 2006). The latest cruise sighting was of a flock of 5 ca. 73 km off Monterey 26 Oct 2012. COMMON MURRE (Uria aalge) Fairly common to common migrant, breed - er, and visitor. Briggs et al. (1987) state that Common Murres prefer to forage in waters less than 150 m deep, although some birds are found up to 100 km offshore. The larg - est numbers (up to several thousand) were found during cruises in waters within forag - ing distance of nesting colonies, less often far- ther away. Common Murres are uncommon to rare in deeper waters just beyond the shelf edge out to about 100 km, and largely absent from deep waters even farther offshore—al - though 1 bird was seen 150+ km off south- ern Oregon 13 May 2015, and 1 was 129 km off Del Norte, CA 12 May 2016. Single adults with chicks were slightly farther offshore than usual at 78 and 86 km off Del Norte, CA 7 Aug 2013. Southernmost were 2 birds just inside Mexican waters near Islas Coronado 15 Apr 2012. THICK-BILLED MURRE (Uria lomvia) A very small population nests, at least for - merly (?), at Triangle Island off the north- western tip of Vancouver Island (Campbell et al. 1990b); the southernmost colonies otherwise are in southeastern Alaska. Single birds were in eastern Queen Charlotte Sound, BC (51.74° N, 129.02° W) 13 May 2011; 50 km east of southern Haida Gwaii (52.11° N, 130.21° W) 6 Jun 2013; and 27 km south - west of southern Haida Gwaii (51.94° N, 131.52° W) 31 May 2014. PIGEON GUILLEMOT (Cepphus columba) This inshore species is fairly common within 5-8 km of shore, but it is rare farther offshore in most regions. Perhaps not surprisingly, small numbers (mostly single digits) are seen regularly by the end of the month, continuing through early October off British Columbia (Kenyon et al. 2009) and later farther south. The high cruise counts were totals of 30 birds off northern Vancouver Island and southern Haida Gwaii on both 17 Sep 2011 and 6 Sep 2015, and 75 between Del Norte and Lincoln 29 Aug 2013. LONG-TAILED JAEGER (Stercorarius longicaudus) Uncommon spring and uncommon to com - mon fall migrant well offshore. A surprising finding of the spring cruises was the earlier- than-expected appearance of this species in numbers: a total of 12 birds seen ca. 55-75 km off Humboldt , CA to Douglas, OR 17 Apr 2012 were the earliest. Also perhaps surpris - ing were the moderate numbers of individu- als encountered later in the spring season, as this species had been termed "rare in spring" by many authorities as recently as 2010; but this belief was likely the result of few single- day pelagic trips getting far enough offshore at this season. Small numbers were seen on almost every cruise between the end of April and the beginning of June. High spring counts included 30 off Curry and Coos, OR 3 May 2007; 19 off Oregon and Washington 1 May 2010; 23 birds off northern Vancouver Island and Haida Gwaii 10 May 2011; 67 be - tween Curry and Tillamook, OR 20 May 2011; a single flock of 14 birds 90 km off Tillamook, OR 29 Apr 2015; and 48 ca. 140-270 km off Curry to Lincoln, OR 13 May 2015 (including a single flock of 26 birds 270 km off Yachats, Lincoln). A few summering non-breeders or failed breeders were seen between mid-June and mid-July. Southbound migrants are seen regularly as early as mid-July (Wahl 1975, Gilligan et al. 1994), with high early-season cruise counts of 10 and 22 birds off northern Brit - ish Columbia (in same area as South Polar Skuas) 11 Jul 2013 and 7 Aug 2015, respec - tively; 10 between Douglas, OR and Mendoci- no, CA 18 Jul 2013; 25 between Humboldt, CA and Tillamook, OR 30 Jul 2013; and 65 between Douglas, OR and Humboldt, CA 7 Aug 2013. Fall migration peaks in many regions between mid-August and mid- or late September (Wahl 1975, Roberson 2002, Wahl et al. 2005, Herlyn and Contreras 2009). Large numbers were found between late August and late September from cruise ships well offshore near and just beyond the shelf edge. Some representative high counts by date and latitude included 386 between

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