The race of Yellow Wagtail found in the UK during the summer months certainly lives up to its scientific name, Motacilla flava flavissima – the most yellow of yellows. The male is a stunning bird with striking yellow underparts that extend up onto the face and greenish-yellow upperparts. Females and young birds are less brightly coloured, and may be confused with other wagtail species. Brush up on your wagtail identification with our BTO id video.
Yellow Wagtails arrive on their UK breeding grounds from early April and peak arrivals occur in the first week of May, according to birdwatching records collected through BirdTrack. Comparison of BirdTrack records with those collected through the Inland Observation Point survey, which operated in the 1960s, shows that the mean arrival date for the species is now four days earlier than it was. Interestingly, the average departure date has also shifted by four days – though in the other direction, meaning that Yellow Wagtails now spend just over a week longer in the UK than they did during the 1960s. The implications of this for their breeding success and annual migrations are unclear.
Our Yellow Wagtails winter in West Africa, and there is evidence that individuals may return to the same wintering sites in subsequent years. The birds typically congregate at communal roosts, a behaviour seen at other times of the year, and something that has made the species particularly amenable to scientific study by ringers. Even with this information there is more that we need to learn about their migration, most notably the routes used and the sites visited when birds ‘stop-over’ to refuel.
Yellow Wagtails favour damp habitats, such as wet meadows, grazing marshes and river valleys, but there has been much greater use of arable habitats over recent years, with oil-seed rape, legume and root crops increasingly used for breeding. The nest itself is placed in the ground, often in a hollow or partly sheltered by a clod of earth. Constructed of grasses, the nest cup is thickly lined with hair, wool or fur and it is into this that the clutch of five or six eggs is laid.
Yellow Wagtail populations have been in rapid decline since the early 1980s and the species was added to the Red List of birds of conservation concern in 2009. Breeding populations declined by nearly 75% between 1967 and 2013 and data from Bird Atlas 2007-11 reveal that the species has been lost from the margins of its UK breeding range, which is largely restricted to central and eastern England and the Welsh Marches. The species has also disappeared from large parts of East Anglia, where it used to be a familiar breeding species. It is thought that land drainage, the conversion of pasture to arable and a decline in invertebrate numbers (notably those associated with livestock) may be behind the decline.
Catching up with the Yellow Wagtail
The association with livestock is particularly evident when Yellow Wagtails first arrive in spring, with individuals feeding around the feet of cattle and other grazing livestock. Passage birds (in both spring and autumn) are often encountered on coastal sites, where short turf and grazing marshes present other opportunities for foraging. It is at these sites that some of the other races of Yellow Wagtail may be encountered. There is a lot variation in plumage across the Yellow Wagtail races, with some of the ‘blue-headed’ races, notably the Central European flava race, occasional visitors to our shores. Autumn passage peaks in the last week of August or first half of September; favoured sites are often used over several years, so a look at your local bird report is a good place to start if you want to go and see this species.