This summary is taken from a post written by Jeremiah Trimble and posted to MASSbird:
This weekend 58 lucky birders explored the offshore waters of Massachusetts, south of Nantucket.
It was an absolutely incredible trip,and that is an understatement. To the say the trip was a success would be an understatement! We found our first ever White-tailed Tropicbirds (andhad two species of tropicbird in one day!), set trip high counts for White-faced Storm-Petrel, Audubon’s Shearwater, Band-rumped Storm-Petrel
and Pomarine Jaeger and had such an amazing variety of rarities on top of these including Black-capped Petrel, Bridled Tern and South Polar Skua. In a later email, I will provide a narrative of the two day trip but to summarize, here are the major avian highlights in brief:
2 Black-capped Petrel
202 Audubon’s Shearwater
28 White-faced Storm-Petrel
161 Leach’s Storm-Petrel
23 Band-rumped Storm-Petrel
4 White-tailed Tropicbird (two adults and 2 immatures)
1 Red-billed Tropicbird (an immature bird)
17 Pomarine Jaeger
1 Long-tailed Jaeger
1 South Polar Skua
1 Bridled Tern
2nd Cal-yr Bridled Tern
Imm Red-billed Tropicbird
Imm Red-billed Tropicbird (left) and Imm White-tailed Tropicbird. This composite of two birds seen on this trip shows the important pattern of the greater coverts – blackish on Red-billed Tropicbird and white on White-tailed. Talking with Nick about assessing this in the field is essentially the dark primaries extend only 1/2 way up the leading edge in White-tailed.
Adult White-tailed Tropicbird – a world tick and a bogey bird for me finally laid to rest!
Adult White-tailed Tropicbird
2nd Cal-yr Pomarine Jaeger (all juv primaries replaced with p10 almost fully grown)
3rd Cal-yr Long-tailed Jaeger. A cool bird and my first non-juv/adult plumage. Aged by the largely brown underwing and dark cap. Although the markings on the breast seemed suggestive of a breast band and the tail projections looked spikey, any initial thoughts of Parasitic were dispelled by a combination of features and behavior, notably the short bill, grey-toned upperparts with a darker trailing edge and 2-3 white primary shafts all being pro-Long-tailed. While discussing it with Nick Bonomo, he brought attention to the lack of any white primary bases on the underwing as a pro-LTJA feature – in itself possibly diagnostic (?) for this age for LTJA.
Adult Pomarine Jaeger. Broken breast band and clean flanks suggest male. Note inner primary moult taking place; an adult jaeger in late August in primary moult is almost certainly a Pomarine; both Parasitic and Long-tailed are not moulting.
2nd Cal-yr Pomarine Jaeger at sunset
The CT contingent of the trip (photo courtesy of Tina Green)
Here are links to two general checklists for each of the two days of the trip which include great images by Jeremiah Trimble.
We would like to first of all thank Ida Giriunas, as always, for her efforts
in organizing and pushing for these trips to happen. She has helped so many birders enjoy the offshore birds of Massachusetts! Thanks!
Also,thanks to Captain Joe Huckemeyer and the crew of the Helen H.
Thanks as well to my fellow tripleaders; Nick Bonomo, Doug Gochfeld, Julian Hough, and Luke Seitz.
Their skills at identifying and spotting birds, communicating to participants and getting everyone on each bird was critical.