Bird News, and ID questions, from Nial Moores
In the early hours of the 25th, Typhoon Goni produced some strong winds, heavy rain and top quality urban birding in Busan as it battered Kyushu and started its swan-song into the East Sea. The highlights and ID questions from Gwangali’s “Diamond Bay” and Igidae, at the edge of urban Busan, include:
Streaked Shearwater Calonectris leucomelas. An estimated 6,000 north in one hour at dusk on 25th; and 456 in 90 minutes in the 26th. Almost all were too distant to determine presence or absence of other shearwater species.
Red-necked Phalarope Phalaropus lobatus. Ten on the 25th (including two juveniles) and at least 60 south on the 26th.
Black-tailed Gull Larus crassirostris. On the 26th, large numbers were moving north steadily between 07:15 and 11:45, with 687 counted in one sample 30-minute period. Most were juveniles.
Mongolian Gull Larus mongolicus. One on the 25th, and about 15 on the 26th including one gorgeous First-winter (already white-headed, largely pale below and pale-grey mantled with neat dark rows – strikingly different to American Herring Gulls seen in Canada earlier this month).
Aleutian Tern Onychoprion aleuticus. A conservative 13 on the 25th, comprised of at least ten adults, with several still in near full breeding plumage, and three (or four?, see below) juveniles, with several birds also heard calling (one of which was sound-recorded). This is double the previous national day high-count from last year, and is also the first national sight record of juveniles and also of calling birds. Four or five adults also went south during the morning of the 26th.
- There seems little doubt now that Aleutian Tern is a regular and perhaps even numerous migrant through the East Sea (with some birds also crossing into the Yellow Sea). Not only are there multiple sight-records (from ferries and especially during storms which push birds closer to shore), but recent unpublished research on Aleutian Terns using “geolocators” also provides further compelling evidence of this migration route (M.I. Goldstein et. al., US Forest Service, unpublished data). It is worth noting that all sight records to date in Korea of Aleutian Tern have so far between August 9th and about September 7th. Therefore, to add more Korean (or Chinese or Japanese!) records of this poorly-known species, please bird the coast within the next ten days or so, especially when there are onshore winds or look for seabirds by boat…It would seem best to focus on areas that often have Common Tern flocks and to double-check all birds resting up on flotsam. Key areas to check in Korea probably include much of the the east coast, perhaps Gangneung in particular and especially the Guryongpo Peninsula; headlands and bays along the south coast; and also in the southwest (e.g. around Heuksan Island).
Unknown tern: Bridled Tern Onychoprion anaethetus (?) or Aleutian?. A juvenile digiscoped at great distance on the 25th seems close to Bridled in some features, but not in others (see below for more images and a description). Searched for on the 26th but not re-found. If identification as Bridled (and not as a dark juvenile Aleutian or even a Grey-backed) is correct, this would be the third national record, with previous records both being of adults on Jeju.
Common Tern Sterna hirundo. A conservatively estimated 1,200 in “Diamond Bay” on the 25th and 2,273 terns counted flying south on the 26th between 07:15 and 11:45 were likely to be almost all Commons (many were too distant to identify with confidence).
Arctic Tern Sterna paradisaea On the 25th one adult, which although distant seemed to tick all the boxes and two juveniles which might have been this species or might have been small-end, very pale juvenile Commons (see below).
Pomarine Skua Stercorarius pomarinus. One south on the 26th.
In rather more detail…
In dawn rain on the 25th, I could see a couple of hundred Common Terns in “Diamond Bay” through my scope from the apartment (near the office in east Busan). One of these fairly distant terns stood out, being strikingly clean grey and white with a silvery look to the outerwing: spot-on for a full breeding-plumage adult Arctic Tern…Fifteen minutes later, I was out in the storm, sheltering from gale-force winds and rain on the concrete waterfront, trying to check through hundreds of birds to re-find this potential first for Korea. I failed. Instead, within minutes I had my first close encounter of the day with a breeding-plumage Aleutian Tern, and between 0710 and 0740, I counted 635 terns (all of which I could see were Common) tower up and head south over the apartment blocks.
Over the next hour or two, several hundred more terns arrived in bird-waves, many heading up a concrete-sided inlet past a school and an apartment complex before either heading back north out against the wind, or instead up and south across the city. The vast majority of these birds were clearly Common Tern too (mostly adults in various stages of moult with probably 10-20% juveniles), but an unknown sparrow-like call (very poorly recorded on my camera) revealed another two Aleutians: one adult and one juvenile (the first record of this age-class in Korea). They were flying in gale-force winds and heavy rain at closest within 20m of me, before they too lifted up over the city.
How to get record shots?
Equipped only with a compact digital camera, and with conditions mostly too poor for digiscoping, I tried snapping images handheld of some of the closest birds, focusing on birds that stood out from the Commons. Individual variation and the conditions, however, meant that structure and plumage tones were quite hard to assess, with features like dark secondaries obvious one moment and near-invisible the next. Nonetheless, in among the feeding flocks of terns were a few birds that looked different enough to follow and to re-find and even to get one or two images of. These included one of the two possible juvenile Arctic Terns.
Tentative identification of both juveniles, seen an hour or more apart, was suggested in the field by both birds’ small-headed and small-billed look, coupled with very pale plumage, including a narrow dusky trail in one (see below), and a neat black trail in the other, to the underside of the primaries, and in both birds secondaries that looked plain below and whiteish above. The only decent image(s) of one of these apparently pale, apparently shorter-billed birds is below, with an inset of what I believe to be the same bird a few seconds later as it turned and flew away from me. Is this a pale-end Common or is there anything to suggest Arctic to you in this individual? Please share your thoughts!
There was also an initially exciting long-billed, ragged and whiteish-looking tern (with brown tones to the crown and some brown on the coverts): presumably a First-summer Common Tern (my personal first of that age here).
After five hours, with no battery left, I headed home. Scoping again from the apartment as the rain became lighter, I could see a large flock of terns (120) and gulls (300+) had now started to roost up on the dock side. And one of these was a cracking full breeding-plumaged Aleutian Tern! Back out within minutes, but again failure to find and photograph properly this beautiful bird. Waiting in vain for one to come back in to the dwindling roost, I could see another two juveniles and a couple more adult Aleutians purposefully moving south, two of which were calling.
From the same low vantage point, I could also see another juvenile tern out in the bay that I first thought was most likely an Aleutian, even though it seemed darker above, and lacked any gingery or rusty tones which were weakly evident in the other juveniles . Its flight also seemed a little more languid and elegant too, until it belly-flopped repeatedly into the water, apparently to pick at prey off the sea in front of it. Eventually this interesting dark tern landed on some distant floating silt-traps at the harbor mouth, constantly in and out of view because of the 3-4m waves and resultant sea-swell.
The 50 or so poor images taken through a truly superb Swarovski scope over the next 30 minutes seem to confirm field impressions: the bird looked similar in size to a Common or Aleutian Tern (perhaps slightly larger), with short dark legs (the hint of reddish tones in one or two of the images, but not in others, appears to be from reflected light) and a long black bill and very long, dark-looking primaries. The mantle was dark brown, with what looked to be rows of pale fringes and perhaps darker internal markings; some of the coverts looked paler and greyer; and the underparts were white, with soft grey on the breast sides. The bird had a pale collar, faintly buff, and a striking adult Aleutian-like head pattern, with dark through the lores to the bill base and a wide white forehead. Several of these features seem to fit illustrations and online images of juvenile Bridled Tern, a species I have only seen once before. A couple of the images, however, if not photographic artefact, seem also to show some paler tones to some of the inner primaries, when Bridled should look all dark. A couple of juvenile Aleutian Terns photographed in Hong Kong in late September look pretty dark too, and also lack any cinammon or rust tones. Not knowing much about these apparently similar-looking species, can an “early” dark juvenile Aleutian, perhaps with an unusual head pattern, be safely ruled-out? Can extralimital Grey-backed Tern O. lunata also safely be dismissed?
If you are familiar with these tricky species, please let us know your thoughts: thank you.
Finally, as dusk started to thicken further on the 25th, the rain more or less stopped, visibility improved, and huge numbers of Streaked Shearwater could be seen moving north, with two timed counts of 100 a minute passing during the last hour or so of the day.
On 26th, the weather was much calmer, the outline of the Japanese island of Teima Do/ Tsushima was clearly visible, and seawatching from 07:15 to 11:45 produced large numbers of some species on the move. Most numerous were Black-tailed Gull and Streaked Shearwater moving north and Common Tern moving south, with (as noted above) four or five more Aleutian Tern seen.
The woodland at Igidae also seemed quite birdy, with five Black Paradise Flycatcher, one Blue-and-white and one Grey-streaked Flycatcher, two Eastern Crowned and 3+ Arctic/Kamchatka Leaf Warblers the highlights. The need to search again for yesterday’s dark tern, however, meant I spent little time in the woodland. Unfortunately though, it was clear that most of the terns had already moved on, with nothing but a few gulls, jetskiers and garbage remaining in “Diamond Bay”.