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.

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328 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 Nov 2015 and 25 between Lane and Clatsop, OR 2 Dec 2015; with just 4 seen off Oregon and California 16-17 Dec 2015. Small num - bers are known to winter north to British Co- lumbia waters (Kenyon et al. 2009). Sooty Shearwater numbers are thought to have declined sharply—at least off Califor - nia—from those of the 1970s-1990s (North American Birds 67:154). Some local declines may be attributed instead, however, to shifts in the distributions of the birds and/or their prey within the northeastern North Pacific Ocean (Hyrenbach and Veit 2003). GREAT SHEARWATER (Ardenna gravis) One photographed 115 km northwest of the northern end of Vancouver Island (85 km northwest of Sartine Island), BC (51.36° N, 129.77° W) 5 Aug 2013 (Figure 17) estab - lished the second documented record for Brit- ish Columbia. PINK-FOOTED SHEARWATER (Ardenna creatopus) Uncommon to common visitor in spring and summer. By far the highest numbers occur over continental shelf and inner slope waters (Briggs et al. 1987), and the species is rather rare in deep water beyond the shelf edge. Off California and Oregon, up to 150/day were seen from cruise ships in spring, with 285 there 16 May 2012 and an exceptional 1550 between Santa Barbara and San Francisco, CA 8 May 2013. Presumed spring arrivals north of California included singles off Curry and Coos, OR 2 Apr 2016. Large numbers spend much of the late spring and summer molting off the mouth of the Strait of Juan de Fuca, WA/BC and vicinity, where high counts in - cluded 1400 on 21 May 2014 (early high), 5000 on 17 Jul 2013, 2500 on 19 Jul 2015, and 2300 on 8 Aug 2015. A few individuals were seen a short distance inside the Strait off Neah Bay, WA. In northern British Colum - bia waters, this species may not arrive until June, although 1 was 62 km east of southern Haida Gwaii 18 May 2016, and 35 birds were already off the northern end of Vancouver Island the same day; hundreds were noted off Nootka Island and Estevan Point, central Vancouver Island, on two dates in mid-May (e.g., 650 there 18 May 2016). Off the south - ern half of British Columbia, this species can be very common between June and Septem - ber or October, but it is much less numerous off the northern half of the province (Kenyon et al. 2009). Pink-footed Shearwaters are rare but probably regular in late summer and early vember off much of Oregon and California. Of the small number of individuals seen from fall cruise ships, the earliest arrival in south - ern waters was 1 off Santa Barbara 26 Oct 2012. High cruise counts include just 4 off Oregon 10 Nov 2015. SOOTY SHEARWATER (Ardenna grisea) In spring, migrants appear in the latter half of March, and numbers increase markedly throughout April and typically peak off Cali - fornia between mid-May and September, es- pecially during July–August (Ainley 1976) or May–July (Briggs et al. 1987)—with higher densities later in the season with increasing latitude. In all areas, Sooty Shearwaters are most abundant over continental shelf and up - per slope waters, particularly near and down- stream from stable upwelling areas (Briggs et al. 1987, Kenyon et al. 2009). Cruise ships, however, spend most of their time in waters farther offshore than where the majority of Sooty Shearwaters feed. Large numbers (up to 5000) were seen regularly inshore at the mouth of the Strait of Juan de Fuca, WA/BC; a few individuals were seen as far inside the Strait as off Neah Bay or Sekiu, WA. A cruise- day spent closer inshore than normal ca. 40- 60+ km off Oregon 20 May 2016 recorded 20,000 birds, half of which were associated with a single fleet of trawlers ca. 37 km off southern Curry. But this species was uncom - mon during many days spent well offshore, although occasional maxima reached 1000- 2500 birds. Some 5200 were off Oregon and Washington 17 May 2012; 5000 were between Del Norte and Mendocino, CA 22 May 2014; 3500 were associated with the same fleet of trawlers (see above) 64 km off Curry, OR 21 May 2015; 22,000 were between Santa Bar - bara and San Francisco, CA 8 May 2013; and 10,500 were between Clatsop and Lincoln, OR 21 May 2014. Huge numbers of molting birds were found congregating during May and June in Hecate Strait, east of central Haida Gwaii— see the Short-tailed Shearwater account for details. In southeastern Alaska, the maximum cruise count was of 825 birds off Chatham Strait to Forrester Island 6 Aug 2015. During fall, this species may be uncommon to very common inshore, with the largest counts in Washington and Oregon typically made from shore July–September, sometimes into October (Wahl et al. 2005). Sample high counts well offshore from cruise ships includ - ed 5000 off Pacific, WA 1 Oct 2012, 8000+ off northern British Columbia 10 Sep 2015, and up to 2000/day off Oregon. Late-season highs include 600 off Tillamook to Del Norte, CA 10 identification difficulties and disagreement further cloud its true status after March or early April and before late October or No - vember. One off Clallam, WA 11 May 2012 was somewhat late, as probably was one 28 km west-southwest of Estevan Point, Vancou - ver Island 18 May 2016. One of the most ex- citing discoveries of the San Francisco-Alaska cruises was the very large numbers of molt - ing Short-tailed Shearwaters found mixed with even larger numbers of molting Sooty Shearwaters in Hecate Strait, 50-70 km east of central Haida Gwaii during May and June. Although huge numbers of Sooty Shearwaters were previously known at this season from Hecate Strait (Campbell et al. 1990a), the very large numbers of Short-taileds were not, and they presumably were largely overlooked except for a single report from 1987 (M. P. Force, in litt.). Such numbers of Short-taileds are unknown elsewhere at this season in the eastern Pacific. The first cruise-ship encoun - ter with these molting masses of shearwaters took place soon after dawn on 6 Jun 2013, as the ship was already leaving the favored area frequented by these birds. Some ca. 80,000+ birds were seen in one hour; but an accurate count and determining approximate ratios of the two species was not possible, although it was clear that a sizable number of Short- taileds were present. Two subsequent cruise visits to these waters have allowed for better estimates to be made: 10,000+ Short-tailed, 20,000+ Sooty, and 30,000 Sooty/Short-tailed (probably mostly Sooty) Shearwaters on both 14 May and 26 May (52.76° N, 130.68° W to 53.06° N, 130.83° W) 2014. But the sheer volume of birds present, the difficulties as - sociated with the field identification of many Short-tailed vs. Sooty Shearwaters, and the constant, moderate speed of the cruise ships prevented leisurely studies of the large flocks. Thus, the counts of both species were only approximate. Dedicated visits on smaller, slower boats to study this phenomenon are clearly needed. At least 4 Short-taileds were 25 km w est of central Haida Gwaii 13 May 2016 (Figure 16). Five Short-taileds were still in Hecate Strait, ca. 48 km east of southern Haida Gwaii 16 Jul 2013. In fall, this species is very rare early in the season, and the cruise-ship sailing schedule is mostly over before most Short-tailed Shear - waters appear. As in spring, identification dif- ficulties also cloud its true status before late autumn. Fall abundance increases off Wash - ington typically in late September or early October (Wahl et al. 2005), but the species is not expected until late October or early No -

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