Citrine Wagtail

It is a slender, 15.5–17 cm long bird, with the long, constantly wagging tail characteristic of the genus Motacilla. The adult male in breeding plumage is basically grey or black above, with white on the remiges, and bright yellow below and on the entire head except for the black nape. In winter plumage, its yellow underparts may be diluted by white, and the head is brownish with a yellowish supercilium. Females look generally like washed-out versions of males in winter plumage.