(873) Acanthopneuste borealis xanthodryas.
The Japanese Arctic Willow- Warbler.
Phylloscopus xanthodryas Swinh., P. Z. 8., 1863, p. 226 (Amoy).
Vernacular names. None recorded.
Description. Similar to the Arctic Willow-Warbler but darker and greyer on the head and generally much more yellow below.
Colours of soft parts and Measurements as in the Arctic Willow-Warbler but the first primary is very much larger, measuring 11 to 16 mm., generally over 14 mm.
Distribution. Breeding in Japan, the Kuriles and ?Kamchatka; South in Winter to South China, the Indo-Chinese countries and straggling into South Burma.
Nidification. The nests of this Warbler are like those of the preceding bird, and I have one clutch of eggs which could not possibly be distinguished from those of that species, though they are larger. The majority of eggs in private collections taken by Alan Owston's collectors are so large that they cannot be those of a Willow-Warbler and are probably those of the Japanese Wren.
Habits similar to those of the Arctic Willow-Warbler.