A message from Ian Bushell:
While taking some shots of a Common Darter, I noticed a Pied Wagtail running round the edge of the pond – or more correctly around the edge of the puddle that’s all that’s left of the pond. It made me really happy because this is only the second time I have ever seen a Pied Dishwasher by the pond rather than in the car cark.
Pied wagtails are insectivores, constantly dashing about in pursuit of tiny insect prey, behaviour that makes them very conspicuous in the car park but surprisingly less so in open country or at the edge of water. They do wag their tails but nobody seems to know why.
A pied wagtail (on the left) and a white wagtail: both pictures are from reliable sources but it’s difficult to see what the difference is. The RSPB says that the pied wagtail has a darker back while the white wagtail has a paler belly.
The reserve’s pied wagtails are of the darker coloured subspecies (Motacilla alba yarrellii) that predominates in Ireland and Britain, as opposed to the white wagtail (Motacilla alba alba) of mainland Europe. There is polite scientific argument about how many subspecies of Motacilla alba there actually are, but somewhere around 10 seems favourite. For a while there was somewhat less polite argument as to whether or not M. alba was one species or several, but a study using mitochondrial DNA has concluded that it is definitely a single species.
Sometimes pied wagtails roost in large flocks in towns, crowding into trees in streets or parks, or the roof structure inside large open buildings like a bus station or a marketplace. If there is a pied wagtail roost in Trowbridge or Southwick that you know of, please write and tell us where it is: we would be very interested. Our email address is firstname.lastname@example.org
Header image: Pied wagtail by Radovan Václav (CC BY-NC 2.0) flickr.com