6960 x 4640 px | 58,9 x 39,3 cm | 23,2 x 15,5 inches | 300dpi
Data acquisizione:
24 agosto 2024
Ubicazione:
Pembrokeshire Wales United Kingdom UK
Altre informazioni:
Wagtails are a group of passerine birds that form the genus Motacilla in the family Motacillidae. The common name and genus are derived from their characteristic tail pumping behaviour. Together with the pipits and longclaws they form the family Motacillidae. The willie wagtail (Rhipidura leucophrys) of Australia is not a true wagtail; it was named by early settlers from England from its superficial similarity in colour and behaviour to the pied wagtail but belongs to an unrelated genus of birds known as fantails. Motacilla is the Latin name for the pied wagtail; although actually a diminutive of motare, "to move about", from medieval times it led to the misunderstanding of cilla as "tail". At first glance, the wagtails appear to be divided into a yellow-bellied group and a white-bellied one, or one where the upper head is black and another where it is usually grey, but may be olive, yellow, or other colours. However, these are not evolutionary lineages; change of belly colour and increase of melanin have occurred independently several times in the wagtails, and the colour patterns which actually indicate relationships are more subtle. Wagtails are slender, often colourful, ground-feeding insectivores of open country in the Old World. Species of wagtail breed in Africa, Europe and Asia, some of which are fully or partially migratory. Two species also breed in western Alaska, and wintering birds may reach Australia. They are ground nesters, often in rock crevices on steep banks or walls, laying 3–8 speckled eggs at a time. Among their most conspicuous behaviours is a near constant tail wagging, a trait that has given the birds their common name. In spite of the ubiquity of the behaviour and its observations, the reasons for it are poorly understood. It has been suggested that it may flush up prey, or that it may signal submissiveness to other wagtails. Studies have suggested instead that it is a signal of vigilance that helps to deter potential predators.
