The Western yellow wagtail (Motacilla flava) is a passerine bird in the family of wagtails (Motacillidae). It is widespread in Europe, Asia and North-America, except the far north territories of these continents. It is a common bird in Romania as well, preferring lowland areas, often close to lake or riversides. It is a migratory bird, the population is in Romania between May and October.
The body length is 17 cm, the wingspan 23-27 cm, and weight 14-21 grams. It has the shortest tail among wagtails, but specific to this family of birds, it constantly wags its tale. The feathers of female and male are identical, with black or brownish head and white eye stripe. The back is olive, the underparts and throat are yellow. The wings are grey and white. They feed on insects.
The nest is built in tussocks, the female lays 5-6 eggs. The chicks hatch in two weeks, in another two weeks they leave the nest. At first they are not able to fly, but hide in the dense vegetation. Both parents feed the chicks. If the parents are often disturbed by predators or humans, they will leave their chicks and will not feed them anymore.
The European population is estimated to 7.9 – 14 million pairs, the Romanian population varies between 800 thousand and 1.6 million nesting pairs. The oldest ringed yellow wagtail was 8 years old.