This autumn has been particularly good for Yellow Wagtail passage with double-figure counts from a number of localities, the best of which to date is a count by Simon Towers of 30+ on the old cricket pitch at Yelvertoft on 17th September. Good numbers have also been regularly present at Hollowell Reservoir and they are relatively easy to see on the recently mown, extensive grassy area and nearby shoreline around the Guilsborough Bay ‘point’. At least six were present today, including this rather striking first-winter, which was also present in the same area yesterday.
Unlike the others, which included a mix of adults and ‘diluted colour’ juveniles well into first-winter plumage and an apparently unmoulted ‘brown’ juvenile – the latter well late for this time of year), this individual was much more strongly coloured with a grey head, contrasting bright white throat and broad, flicked-up supercilium. The median coverts, greater coverts and tertials were all new post-juvenile first-winter feathers with clean, broad white fringes contrasting with dark centres. None of the other first-winters approached this rather boldly marked and contrasty individual, which was always easy to locate within the small group.
This bird is a good candidate for first-winter Blue-headed Wagtail (flava) but I believe its plumage probably falls within the range of that of British Yellow Wagtail (flavissima) – despite most of these normally being a rather ‘washed out’ grey with less obvious supercilia. And then there’s the problem of the occurrence of racial hybrids … Whether flava or flavissima it’s a nice bird to see and I would welcome thoughts and comments on its possible racial identity.