Wagtails are a type of passerine birds, notable for their continuous tail pumping behaviour, which have given them their name. Wagtails are slender ground-feeding which breed in Africa, Europe and Asia, some of which are fully or partially migratory. Whilst their tail wagging behaviour is still poorly understood, it is though that its purpose could be to flush up prey or as a signal of vigilance that can help them deter potential predators.
Three species of wagtail visit the Maltese Islands, the White Wagtail (Motacilla alba, Zakak Abjad), Yellow Wagtail (Motacilla flava, Isfar) and the Grey Wagtail (Motacilla cinerea, Zakak tad-Dell). Whilst the White Wagtail is a common winter visitor, the other two species are often migrating whilst visiting the Maltese Islands in Spring and Autumn.
The Yellow Wagtail is a slender 15–16 cm long bird, with the characteristic long, constantly wagging tail. It is very noisy, with a high pitched call, spending much time walking on the ground and feeding on insects. It prefers open country near water sources, and can be noticed by its vibrant yellow underside. During migration, the bird is very social, often feeding and roosting in large numbers. Between 13 and 17 distinct subspecies breed in a wide range over Eurasia and North Africa. In fact, the heads of breeding males have a variety of colours and patterns depending on the subspecies – at least five which visit the Maltese Islands.