A note from the Kumamoto International Ornithology Desk (merged with the Feline Desk due to budget cuts, which, in retrospect, was a bad idea): the white wagtail (Motacilla alba) is a small passerine (perching) bird known in Japanese as “hakusekirei” (ハクセキレイ, 白鶺鴒) - couldn’t find any etymological meanings behind the kanji probably because this bird exudes an attitude of “We don’t need no stinkin’ etymology!” (though it is awesome kanji). Its various subspecies live pretty much everywhere in the northern hemisphere. With a striking black/white plumage in winter, it is known for its active tail movements. Nobody knows the purpose of its active tail movements; perhaps it simply enjoys moving its tail actively. (Wouldn’t you?) It is insectivorous so prefers an open environment where it can hunt down those lower on the food chain - you’ll often see them in parking lots.
When my son was a tot, we called them “pointy birds” after the famous poem by the American poet Steve Martin:
Pointy birds - Pointy, pointy. Anoint my head - Anointy, nointy.
You can read more about the 白鶺鴒 here:
https://en.wikipedia.org/wiki/White_wagtail
- William