Every autumn here in Dorset we witness the southern migration of species that visit Britain solely for the summer months to breed and all sorts of unexpected birds turn up along the Dorset coast. Some passage migrants are predictable and the yellow wagtail (Motacilla flava) is one of these species that always turn up here on their way south. They are usually in flocks, often forty or fifty birds.
They like rough pasture and cows. The cows eat the grass and drop cow pats, the dung flies come along to lay their eggs in the pats and the yellow wagtail make the most of a last meal before setting out across the channel by eating up the flies!
We see less of the yellow wagtails in spring when they are heading north, they have other things on their mind then and are fully focused on breeding. Going back in the autumn it is about building up strength and body mass to help them through the journey having put all of their energy into the breeding season.