For the interpretation of the Middle English gloss wanster (read elsewhere as wasthere, and hence waschere) as a popular name for ‘wagtail’, see OED sub washer n.1 (4.a) and MED washer(e n. (b). The etymology of the Anglo-Norman word, unique to some of the Bibbesworth manuscripts, is obscure. It is not clear from where AND¹’s original definition ‘wheatear’ (a similar small bird, but from the Oenanthe genus) derives.