Date: 6/13/18 5:42 am
From: Shaibal Mitra <Shaibal.Mitra...>
Subject: RE: [nysbirds-l] Breezy Point Queens
Tripper and all,

This is indeed a first-summer Arctic Tern, a long-anticipated first for Breezy Point. This record illustrates three things that need emphasis: the variability of this species and the relative importance of the many subtle characters; the difficulty of identifying this species confidently--and ongoing requirement for thorough documentation for the acceptance of any report on Long Island; and the species’ peculiar, probably unique, mode of occurrence on Long Island, wherein the records are more numerous than in other “rare” species, can be expected to occur in the appropriate highly stereotyped context around any ocean inlet, from Rockaway to Sagaponack, but individual occurrences are nevertheless basically unchaseable.

As you note, its structure differs less strongly from that of Common Tern than those of many Arctic Terns. Both its bill and its legs are larger than those of other recently well-documented individuals, and its overall plumage appearance is also different from the assortment of adult-like, advanced second-summer type, delayed second-summer type, and first-summer individuals recently observed, documented, discussed, and debated. Furthermore, as is often the case, the impression given by this bird varies greatly from image to image. In brief, images ML104255381 and ML104255391 are perhaps the most unambiguous, showing the overall structure (short bill, short neck, long hands, long tail), head pattern (white forecrown extending further back on the head and forward part of face mask triangular and encompassing the eye), and primary pattern (dark tips of individual feathers smaller than on Common Tern) conveniently. In contrast, I’m guessing that image ML104255361 is causing a lot of confusion, as the bill and legs look long and the head pattern looks too much unlike those on some of the motley first-summer Common Terns we’ve been seeing lately. But if the bird is an Arctic Tern an image of this quality should be diagnostic, and it is. The length of the primary projection (the blade of folded feathers extending from the tertials) is longer relative to the overall size of the body than in Common Tern. Furthermore, one can assess accurately the length of the black tip to the outermost primary on the far wing: it hooks back on the inner web for just a short distance, perhaps a centimeter or so (in the field, measure this against the leg and bill, allowing for what you know about their absolute lengths). This feature can be hard to see in individual photos, but it is often readily assessed in the field. Compare the adult and left-hand first-summer Common Terns in image ML104255291: the black on p10 extends more than twice as far along the tip of the inner web. Another point is the color of the legs, a vinaceous, dusky-maroon tone unexpected on first-summer Common Tern. In sum, the structural points reign supreme but are variable and require a lot of familiarity; ditto for the head pattern (and covert patterning and other aspects of body plumage), except that here the variability is even more complicated; the primary pattern is diagnostic, unequivocal when assessed properly, and unvarying among age groups in both species. The only downside with this last feature is that it can be difficult to assess properly from individual images, because of angle, parallax, lighting, etc.

The second point is that this species is difficult to identify and still requires thorough documentation. Every June in recent years I have received photos of prospective Arctic Terns from many, many people, many of whom are highly skilled, careful, and experienced birders. It is remarkable how low the correlation has been between the observers’ initial confidence and the subject birds’ identities: many of the genuine Arctics thus revealed were reported as, “I think this is just a Common Tern, but…” whereas a large percentage of the birds strongly hoped for as Arctics were actually Commons. I suspect that more than a few people viewing Tripper’s images were not completely sure about the identification. Ask yourself honestly, did you think this was a Common Tern? If not, were you completely sure this was an Arctic Tern? I strongly suspect that only a very small handful of people confidently knew the answer, understood why, and would be able to explain it. If so many of our best birders are unsure, even given this long series of high quality images, then how can we trust sight records, which nowadays usually imply poor, distant, and brief views?

Thirdly, this record, along with Tripper’s discovery earlier this spring of an adult Arctic Tern at Plum Beach, should establish definitively that this species occurs in its intriguing, almost inscrutable fashion, at ocean inlets all along the outer coast of Long Island. The first five Arctic Terns I found on Long Island were at Democrat Point, Fire Island Inlet, in 1999-2000. I didn’t find another one until I resorted to tern therapy to calm myself while baby-sitting Ken and Sue’s Bar-tailed Godwit at Mecox Bay in 2004. All of these records were genuinely a big deal at the time. It was not until 2005 that Pat and I found the first one at Moriches Inlet, precipitating the now-familiar cottage industry of tern ogling, phone dunking, and margarita guzzling there. Earlier, P. A. Buckley had found them on the inaccessible bars at Shinnecock Inlet, and eventually we managed a couple from that area, too. Later, Donna Schulman, John Shemilt, and others proved that the early Mecox bird was not a fluke by finding several there. Far to the west, Nickerson Beach has produced the steadiest stream of records over the last five years or so, owing in part to its accessibility and the off the charts concentration of camera attention. More recently, proving the point in an elegant scientific experiment, Derek Rogers has found Arctic Terns at Long Island’s newest inlet, Old Inlet, which re-breached after Sandy. Lastly, we have Tripper’s two records from Rockway Inlet already this year. To my eye, there is no peculiar concentration of records at Moriches Inlet, just a prolonged period of good conditions and thorough and competent coverage. As the precise positions favored by loafing flocks of non-breeding terns shift around, and as observers become more numerous and more familiar with this species, we will surely continue to see more and more records from a variety of sites—but we will only understand this based on well-documented reports.

Shai Mitra
Bay Shore

________________________________________
From: <bounce-122635039-11143133...> [<bounce-122635039-11143133...>] on behalf of peter paul [<pepaul...>]
Sent: Wednesday, June 13, 2018 5:14 AM
To: nysbirds-l; Ebird NYC
Subject: [nysbirds-l] Breezy Point Queens

Last evening I had a possible Arctic Tern at Breezy point in Queens. The jury is still out, and thoughts would be welcome. Images of the bird can be seen below in my ebird report, and from flickr. The bird stuck around for about 6 minutes before flying off, and I was unable to refind it (though I didn't stay terribly long looking). Winds were strong from the SSE, and terns were constantly rotating though - there were at least four first summer COTEs and one second summer bird over the course of my observation. Details here:

https://ebird.org/view/checklist/S46510785

https://www.flickr.com/photos/129132563@N05/ and

Happy terning,
Tripper


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