The White Wagtail is a highly variable bird found from Western Europe and North Africa through Asia to the very edges of Alaska. Within this region, many distinct races exist with the majority of birds in Japan being M. a. lugens - the Black-backed Wagtail. This race has been considered as a separate species at times, but most authorities currently include it as part of the White Wagtail species. They are fairly common, occurring in a range of habitats from agricultural settings to parks, but often near water. They are usually insectivorus, darting around to catch flies. They are smaller than the similar Japanese Wagtail at 16-18 cm, which is not usually found away from rivers and streams.
1: Photon Factory KEK, Tsukuba, 19/05/2012.
2: Imperial Palace Gardens, Tokyo, 17/05/2012.