Why grey wagtail is a little off colour

I HAD an unusual visitor to the bird table the other day — a grey wagtail. This has to qualify as the bird with the most inappropriate English name.

The pied wagtail is black, white, and grey. This is the common ‘willie wagtail’ found everywhere, in towns and the countryside. I regularly visit schools, and, for some reason I don’t understand, pied wagtails have a passion for school yards. I don’t think there’s a school in the country that doesn’t have a pair.

The grey wagtail is nothing like as common. It is a slimmer bird, with an even longer tail that it continuously wags up and down. The most striking characteristic of the grey wagtail is its under-part, which is bright, primrose yellow.