April is the month when a large proportion of our breeding Yellow Wagtails return to the UK. Look carefully at any Yellow Wagtails you encounter this month, as there may be a sneaky Blue-headed Wagtail there. These are scarce wanderers from the continental breeding population. Males have lovely blue heads with a clear white supercilium (‘eyebrow’). The throat is yellow on the purest birds (intergrades occur between the various subspecies of Yellow Wagtail).