Dr. Nial Moores, Birds Korea, July 11th 2015
We need to revise the Birds Korea Checklist, so that an up-to-date checklist can be included in the Korean language version of Status of Birds which is now under development. Would you like to contribute some of your identification skills, experience and opinions to this process? If so, please just add your comments. Thank you!
First, some essential background to the Checklist and then a decades-old identification challenge.
The last Checklist version was posted online at the end of April 2014 and was published in September in the English-language Status of Birds, 2014. To avoid repeating information at length here, please read through the category descriptions and status codes. Most importantly for this post, if a claimed national first record is supported by a photograph or sound recording that enables identification then the species should be listed in Category One. If not, then the species should be listed in Category Four or removed from the list. It cannot be stressed strongly enough, this process is not an assessment of the observer who made the record. Instead it helps us to maintain a consistent standard when there is no national committee to assess such records.
The Checklist with its species, subspecies and status codes needs constant updating. There are frequent improvements to the IOC Checklist, new breeding records and / or records that signal or require a change in the status of taxa recorded in Korea. These include this week’s Eurasian Bittern Botaurus stellaris in Suncheon, which requires the adding of SV2 (rare in summer with fewer than ten records) to the species’ existing status code.
After a week of review, with much valuable help from several people already and a lot of specialist literature, I have found 50+ revisions that I think we need to make. Some are simple revisions to follow IOC name changes, and taxonomic changes affecting subspecies. Others are to do with status codes (as with Eurasian Bittern above) and category allocation.
As part of an effort to improve transparency and to benefit from everyone’s expertise, from now I would like to use a series of blog-posts to help build consensus on proposed changes, giving everyone (members or otherwise), a better chance to discuss identification issues and the status of species more publicly.
Among several long-standing identification issues that would be great to resolve is the ROK’s only record of Wilson’s Phalarope Phalaropus tricolor from 1996. This record is included in Park (2002), in OSK (2009) and in Park (2014) and most other lists. At present, however, Wilson’s Phalarope is in Category Six of the Birds Korea Checklist.
Category Six is a kind of public online file for decisions that are still pending. These are species that have already been listed, one way or another, in other formal checklists or in books on Korean birds. Yet, as far as we know, these species either have no images, sound-recordings or specimens to support them; or they are supported by images that seem ambiguous at best. Should they be included in Category One (if there are images)? Or in Category Four (if a first-record without what we call “adequate documentation”)? Or should they instead be rejected, and removed from the list? Again, this is not to do with the competence or the honesty of the observer(s). It is instead about ensuring that our national checklist can be trusted and used by people 50 years from now, without knowing anything about the observers.
Back in 2005, wanting to know more about the Wilson’s Phalarope record, I mailed with Onishi Toshikazu (a well-known birder and bird-book author). He told me that his friend, Kozono Shigeru visited Ulseuk Island in the Nakdong Estuary in Busan on October 22nd 1996. He only had a 300mm lens with him. On this visit to the estuary he found two Wilson’s Phalarope together and took a series of poor images that were then printed in the May 1997 edition of the Japanese-language magazine BIRDER. OT kindly scanned the best images and sent them to Birds Korea.
These are the images.
What do you think?
It is quite possible that the images in the magazine itself are much better and clearer than this. The description accompanying the images might also provide key information to confirm the identification as two Wilson’s Phalarope. We do not have that information, however, and we assume that information is also not widely available in Korea because, for example, both Park (2002) and the nation’s best field-guide (Park 2014) indicate there was only one bird. This suggests that the record has probably never been properly “reviewed” by an independent committee, and probably most birders here have not questioned the identification, even though there have been no subsequent records in Korea and even though until 1990 (at least) there had only been two records of this species in Japan: once in May 1985 and once in July 1986, both at the same site. As both probably relate to the same individual (Brazil 1991), it seems that Wilson’s Phalarope really is / was an extremely rare vagrant to East Asia.
If we only have these images, should we accept this record as Korea’s first Wilson’s Phalarope? Please share your thoughts.
In my opinion we should not.
Why? In the three images, there appear to be a total of three shorebirds. Based on structure and contrast, two appear to be of the same species (left-hand image). The image on the right shows a ‘shank standing behind a bird in the water in front. On leg and bill colour, this ‘shank is clearly either a Spotted Tringa erythropus or a Common Redshank Tringa totanus. Although the bill looks very long, there seems to be red on both the lower and upper mandibles. Also, the hint of white adjacent to the primaries fits well with a Common Redshank, as do some of the head markings (e.g. the lack of clean white on the supralorals). Either way, this bird helps us to assess the size of the claimed phalaropes. Common Redshank, which is how I would identify this bird, has a total length of about 28cm. The bird in front in the water is at a different angle to the bird behind. Without allowing for any adjustments for angle, it looks to be about the same length as the (presumed) Common Redshank, as measured from the nape to the tip of the primaries. Allowing for angle is difficult, but the bird in front looks to me to be perhaps 20- 25% (?) shorter than the bird behind, at most. It is therefore probably somewhere between 21cm and 23cm in length. The length of Wilson’s Phalarope given by Chandler (2009) is 23cm, a good match. The bird is in water, which is something you might also expect of a phalarope. In common too with Wilson’s Phalarope, the bird is largely grey above, with slightly darker wing coverts and a prominent dark streak on the ear coverts. So far so good…
There are several structural features suggested by these images, however, that do not fit well with my impression of Wilson’s Phalarope. Although I have only seen the species a few times, the most striking problem is the bill, especially how it looks in the right-hand image. It looks quite thick at the base, and the bill base also looks much paler and greenish. Wilson’s should have a knitting-needle thin and all-black bill at all ages. The bills of both birds seem to be either about the right length for Wilson’s or a little on the short side (similar to the width of the head). We cannot see the legs. However, although Wilson’s swim well, neither of the birds look to me to be swimming in the images. Rather, based on their posture, the reflections in the water, the lack of ripples, and the hint of flank or upper tibia feathering apparent in the middle image, they instead look to be wading in the water up to but not beyond belly depth. As the redshank is standing on a shelving bank, and they are off from the bank, this suggests that either they are long-legged or that they are both somehow wading on a ridge in the water: not behaviour you would expect in a rather short-legged species that swims and walks well. Moreover, when swimming and even when running, Wilson’s seem often to push their thin neck forward. Because they seem to have quite a full abdomen, this often gives a nice smooth curve to the underside of the bird (like a white banana, greyer on top). In all three of these images, however, the neck looks thicker, the head a little heavier, and there is an obvious step from the belly to the abdomen. To me this gives both birds the feel of a ‘shank or calidrid.
There is also some unexpected contrast in the plumage. The contrast that we see suggests that both birds should be First-winters. According to Chandler (2009), juvenile Wilson’s Phalarope moult early, so this plumage state is consistent with the identification as Wilson’s. He describes this 1w plumage as follows, “Crown grey; white supercilium, sometimes in front of eye only; upperparts grey with narrow white fringes. Entire underparts white…Retains dark-grey juvenile wing-coverts and perhaps some tertials”. I cannot be sure, but the middle image seems to show a bird with pale grey upperparts that look a little scaley (most likely caused by pale fringes) which contrast with obviously browner-looking coverts, and with the tertials which all look darker, lacking obvious paler fringes. Moreover, most Wilson’s show some dark on the lores (even if just a loral spot). The right image suggests that this bird is white on the lores, with no loral spot. The forehead also really seems to be white, so that the darker on the crown (which looks browner-tinged in the central image) looks more like a cap.
To me, this combination is more suggestive of Marsh Sandpiper than a phalarope. Marsh Sandpiper has a total length of 23cm. Its bill length is about one head’s width. Although finer-billed than Common Greenshank, Marsh Sandpiper has a thicker bill than Wilson’s Phalarope and many First Calendar-years show a greenish bill base like the bird in the righthand image. Like most other ‘shanks too, Marsh Sandpiper has a deep belly and slimmer abdomen, so there is often a visible step in the profile of the underside. They are long-legged and feed almost habitually by wading, often belly deep, into the water. They also often associate with other ‘shanks, like Common Redshank. Super-smart in breeding plumage, Marsh Sandpipers in First-winter plumage simply look pale: grey-backed with contrasting browner wing coverts and darker tertials. They have strikingly white foreheads, lacking a dark loral spot, and a darker eye-patch that runs back to the nape.
If I had been sent these images without knowing what they were supposed to be, I would have said they were most likely Marsh Sandpiper. This ID is based on structure, behaviour, bare parts patterning, plumage and even what we know of migration strategy.
Do you agree, or disagree? Is there still a good reason to identify these birds as Wilson’s Phalarope? Should this species be added to Category One? Or to Category Four? Or should it be removed from our Checklist?
Please add your comments.
References
- Brazil, M. 1991. The Birds of Japan. Published by Helm.
- Chandler, R. 2009. Shorebirds of the Northern Hemisphere. Published by Helm
- OSK. 2009. Checklist of the birds of Korea. Seoul: Ornithological Society of Korea (in Korean).
- Park J-Y. 2002. Current status and distribution of birds in Korea. Department of Biology, Kyung Hee University, Seoul (unpublished thesis, in Korean).
- Park J-G. 2014. Identification Guide to Birds of Korea. Checklist of Organisms in Korea 12 (series). Nature and Ecology Publication (in Korean).