In a paper written in the Ibis (1927: 692-723), Kuroda lists several new subspecies described by him between 1915 and 1925, with their suspected range and measurements. These include four endemics to Ulleung Island off the east coast: White-backed Woodpecker Dendrocopos leucotos takahashii. Varied Tit Sittiparus varius utsurioensis (one of three Varied Tit subspecies in Korea described in the paper); Eastern Great Tit Parus minor dagetelensis; and Grey-capped Greenfinch Chloris sinica clarki. Of these four taxa, only takahashii seems to be still popularly recognized, and is included in e.g. Brazil (2009). The Birds Korea 2014 Checklist for now also still lists the rather unconvincing dagetelensis (though as Data Deficient). Notably and in contrast, differences in plumage (and greater bill length) of the utsurioensis Varied Tit increasingly appears sufficient to reinstate this forgotten Ulleung-endemic taxon.

According to Kuroda (1927) the type specimen of the takahashii White-backed Woodpecker was slightly shorter-winged, shorter-tailed and smaller-billed than subspecies stejnegeri (found in Honshu) and based on measurements given in Tomek (1999) it appears also to have slightly shorter wings and tarsi on average than nominate leucotos from DPRK. However, such differences might well be insignificant as the full range in measurements given in Tomek (1999) is far greater than the difference in means between the larger sample size of leucotos and the very small sample size of takahashii: i.e. individual variation in measurements is perhaps greater than the difference between subspecies.

Takahashii, as well as being geographically isolated, also shows plumage differences from “neighboring” subspecies of White-backed Woodpecker. Vaurie (1959) states of takahashii: “differs from nominate leucotos by being much darker. In the only specimen that I have seen the feathers of the rump have black shaft streaks, the white spots are smaller, and the white bars on the wings are narrower, than in nominate leucotos, and the sides of the breast and flanks are also much more heavily streaked with black…stejnegeri of northern and central Hondo (=Honshu), and namiyei of southern Japan are more buffy, less white, in the breast than in the specimen of takahashii…the wing (is) longer in stejnegeri.”

It appears that little subsequent research has been conducted or published on takahashii. A domestic literature search failed to find any papers on it; and little appears to be available in English-language literature beyond what is re-presented here. Therefore, there appears to be no formal population estimate for this taxon and no detailed understanding of its breeding ecology and habitat requirements. This is quite remarkable considering that this taxon is endemic to Korea (host of the 2014 Convention on Biological Diversity Conference of the Parties); and that takahashii is likely to prove the second rarest bird taxon at the global level still-found in Korea (with another woodpecker, Tristram’s Woodpecker Dryocopus (javensis) richardsi, believed at present likely to be the rarest, followed by the fast-declining and globally Critically Endangered Spoon-billed Sandpiper Eurynorhynchus pygmeus).

Fig. 1: White-backed Woodpecker Dendrocopos leucotos takahashii, Ulleung Island, November 4^th 2014, © Nial Moores

A total of ~10 days of survey work on Ulleung Island in October and November 2013 and 2014 covered between 5% and 10% of the island. During this time, one migrant Great Spotted Woodpecker and seven “Ulleung Woodpeckers” were encountered (if there was no double-counting). Takahashii was found in only three out of about ten areas that superficially appeared suitable. Five of the seven encounters were in deciduous and mixed woodland; and two were in mixed forest dominated by coniferous trees. Although most of Ulleung is still forested, initial impressions are that the total population of this taxon will likely be quite small (perhaps as low as ~100-200 individuals, including birds of the year).

Fig. 2: White-backed Woodpecker
Dendrocopos leucotos takahashii,
Ulleung Island, Movember 4^th 2014, © Nial Moores

In each case, birds were found by calls (four times) or by pecking. Pecking by five different individuals was heard, and each time seemed less aggressive and persistent than is typical of on the mainland, making birds rather harder to locate. On November 4^th, one individual was watched feeding for almost thirty minutes. Like the others, it was not seen to feed on or close to the ground. Instead it seemed to be feeding on insects found under the bark of quite thin branches, probably mostly ~5m off the ground, rather than buried within the main trunk of the tree or in thicker branches. Prey was apparently extracted by short series of light pecks, made both while hopping along the top and the underside of quite narrow branches. Feeding was interrupted by periods of sitting crossways across the same branches, sometimes sitting up (somewhat thrush-like). This individual, as the others that had been seen more briefly, seemed to lack the muscularity of typical leucotos (especially in the neck) and like the other individuals also looked quite slender-billed. Like the other individuals, it also appeared quite dark on the upperparts, with much less extensive white on the lower back.

We would welcome receiving any information on and images of takahashii (and also of Ulleung Varied Tit). This will be helpful to Birds Korea’s work and also to an ongoing review of various White-backed Woodpecker taxa by Jean-Louis Grange and other woodpecker experts in Europe.

With thanks to Mr. Ha Jung-Mun for conducting a review of domestic literature and to M. Jean-Louis Grange, for sharing the papers by Kuroda and Vaurie.

Fig. 3: All images same individual of White-backed Woodpecker Dendrocopos leucotos leucotos, Goseong County, Gangwon Province, October 30^th 2014, © Nial Moores

References

• Brazil, M. 2009. Birds of East Asia. Helm Field Guides.
• Kuroda N. 1927. A List of the Birds described by the Author during the ten years from 1915 to 1925, with descriptions of two new forms. Ibis 1927: pp 691-723.
• Tomek, T. 1999-2002. The birds of North Korea. Acta Zoologica Cracoviensia 42: 1-217; 45: 1-235 (in English).
• Vaurie, C. 1959. Systematic Notes on Palearctic Birds. No. 35 Picidae: The Genus Dendrocopos (Part 1). American Museum Novitates. Number 1946. Published by the American Museum of Natural History, New York (June 1959).