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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331 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 (35.06° N, 121.55° W to 35.17° N, 121.62° W) 16 Sep 2015. BLACK STORM-PETREL (Oceanodroma melania) Common in inshore waters out to ca. 50 km off San Diego, CA and Baja California by mid-April (e.g., 200 there 15 Apr 2012, 250 tallied 14 Apr 2013, and an exceptional 3000 on 28 Apr 2014). Not typically found north of Point Conception until following the nesting season in late summer and early fall: e.g., 1 was at Cordell Bank, Marin, CA 29 Jul 2013. Rare north of Marin and southern So - noma. Very rare in deep water well offshore. Exceptional were single Black Storm-Petrels seen ca. 95 km off Lincoln, OR 21 Sep 2010 and (unreviewed by Oregon Bird Records Committee) ca. 65 km off Coos, OR 27 Sep 2010. Single Black-type Storm-Petrels were noted 65 km off Gold Beach, Curry 3 May 2007 and 125 km off southern Curry (42.16° N, 125.87° W) 1 Aug 2015, but the similar Tristram's (O. tristrami) or Markham's (O. markhami) Storm-Petrels were not ruled out (cf. Pyle 1993). Peak numbers of Black Storm-Petrels are typically found off Califor - nia between August and early October, asso- ciated with warmer waters. Tropicbirds through Ibis –––––––––––––––––––––––––––––––––––––– RED-BILLED TROPICBIRD (Phaethon aethereus) Casual visitor. Most likely to be found off California between May (especially July) and early October (Ainley 1976, Briggs et al. 1987). Most cruise-ship routes are north of the waters typically frequented by this spe - cies, especially in spring and early summer. Thus, 3 birds 48-66 km off western Santa Barbara and 1 bird 60 km southwest of Point Sur, Monterey, CA (35.99° N, 122.44° W) 7 May 2014 were unexpected. In fall, 1 was 74 km southwest of Davenport Santa Cruz, CA (36.575° N, 122.824° W) 27 Sep 2011. BROWN BOOBY (Sula leucogaster) None seen during spring and summer cruises north of San Diego and Los Angeles, CA, but there were several fall sightings from cruise ships north to British Columbia, where casual: 66 km southwest of Shelter Cove, Humboldt, CA (39.69° N, 124.71° W) 2 Oct 2012; 34 km west of Estevan Point, central Vancouver Island (49.34° N, 127.04° W) 4 Sep 2013; 90 km west of Long Beach Peninsula, Pacific, WA the shelf break and for 25 km farther offshore (Briggs et al. 1997). The earliest individual from a cruise ship was off northern California 20 Mar 2015, corresponding with the earli - est cruise date. Very uncommon in spring well offshore south to Santa Barbara, CA; 14 off that county 2 May 2013 made a high count for that season well away from the breeding col - ony at San Miguel Island. The highest cruise counts in spring and summer were of just 30 birds at Cordell Bank Marin/Sonoma (not far from the Farallon Islands), CA 29 Jul 2013 and 55 birds between Monterey and Mendoci - no, CA 4 May 2016. North of southern Men- docino (where a high of 7 seen 3 May 2016), this species is very rare before late summer. Off southern and central Oregon in spring, 6 birds were seen 73 km off Coos Bay, Coos 3 May 2007; 1 was off Curry 20 May 2011; 1 was 65 km off Curry 30 April 2014; and 6 were off Coos, Douglas, and Lincoln 1 May 2014, of which 1 bird—ca. 80 km off Reed - sport, Coos—was accepted by the Oregon Bird Records Committee. Some of the above reports have not been submitted to the Com - mittee. A record of 1 seen 14 May 2012 was not accepted due the brevity of the sighting and lack of photographs. Also, 1-2 birds were off Grays Harbor, WA 1 May 2010, but that record was not accepted by the Washington Bird Records Committee. Larger numbers off California are found during late summer and fall, including well away from the breeding sites, and there is also a limited northward dispersal at that season, as far north as off Eureka, Humboldt (Briggs et al. 1987). A huge aggregation of ca. 10,500 birds (including 9500 in a single raft) was off San Francisco, CA 30 Sep 2008. Nine were reported off southern Oregon 31 Aug 2009, but only one of these was accepted by the Committee (50-55 km off Curry), and singles were reported 81 km west of Florence, Lane (44.00° N, 125.17° W) 18 Oct 2014 and off Lane 20 Jul 2015. High late-season counts as - sociated with late cruises were 30 birds be- tween Marin and San Luis Obispo, CA 11 Nov 2015 and 28 birds 57-81 km off San Fran - cisco, San Mateo, and Santa Cruz, CA 17 Dec 2015. Other sightings seaward of the conti - nental slope after December suggest an off- shore shift in winter (Briggs et al. 1987). WEDGE-RUMPED STORM-PETREL (Oceanodroma tethys) This casual visitor to California waters was recorded once from a cruise ship: 2 birds were photographed 63-66 km west- southwest of Point Buchon, San Luis Obispo WA 9 May 2014, and 1900 off Grays Harbor and Pacific, WA 21 May 2014 (which included 500 at a single slick 90 km off Cape Shoalwa - ter). Higher still, some 2500-3500 birds were 50-80 km off Humboldt and Del Norte, CA 17 Apr 2012 and a staggering 12,000 were ca. 48-53 km off Jefferson and Clallam, WA 10 May 2013. Leach's Storm-Petrel is a very com - mon breeding species in British Columbia and southern Alaska, but even there, most birds are observed at sea over deeper waters. Off Brit - ish Columbia, at-sea surveys found this spe- cies mostly between May and October, with very few records during other months (Ken - yon et al. 2009). Sample high cruise counts off British Columbia—between Haida Gwaii and central or southern Vancouver Island—by month included 2000 on 14 May 2014, 2600 on 6 Jun 2013, 3300 on 9 Jul 2014, 7200 on 5 Aug 2013, and 800+ on 17 Sep 2011; those in southeastern Alaska were concentrated near Forrester Island, which is a major nesting site: 1300 on 19 May 2014 is the high count. Small - er numbers breed from Washington to Califor- nia, and peak daily cruise totals in summer and early fall from those states were: Washington: 800 on 17 Jul 2013, 2000 on 19 Jul 2015; Or - egon: 300 on both 18 Jul and 7 Aug 2013, 850 on 20 Jul 2015; and California: 350 on 18 Jul 2013. Off Oregon, the largest concentrations were typically off Curry and Coos. Numbers decline after August or Septem- ber (Briggs et al. 1987), when most birds move far offshore or south. All single-day cruise counts were of fewer than 5 birds. A few individuals were seen as late as Novem - ber and December, with the latest birds cor- responding with the latest cruises: 2 were 98 km off Tillamook, OR 2 Dec 2015 and 1 was 71 km south-southwest of Southeast Farallon Island, San Francisco, CA 17 Dec 2015. A few birds may persist in winter in warmer water 100+ km offshore (Briggs et al. 1987). No birds seen from cruise ships were iden- tified as definite or even probable "Chap- man's" Leach's (O. l. chapmani) or Townsend's (O. socorroensis) Storm-Petrels, the latter only recently split from Leach's. These Mexican- breeding taxa are most likely to be found off southern California between July and October (Howell et al. 2009), when cruise ships barely traverse some of these waters during daylight. ASHY STORM-PETREL (Oceanodroma homochroa) Most numerous (uncommon to fairly com- mon) off northern California, particularly near the Farallon Islands, where the species is a common breeder. Found regularly to near

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