BTO Bird ID - Yellow-coloured wagtails

Wagtails, as a family, tend to be rather easy to identify. They're ground-dwelling, elongated, horizontal birds with long tails which, as their name suggests, they wag up and down persistently in an almost hypnotic way. Add to that our familiarity with the ubiquitous black and white pied wagtail and it is easy to see how, when faced with an unfamiliar plumage, it could still be very easy to correctly determine that you are looking at a wagtail without knowing which wagtail. So, how can we work out what the species is? The first thing to bear in mind is that yellow on the bird does not necessarily mean it is a yellow wagtail. It's a common mistake. There are three commonly encountered species in the UK and Ireland and all three can show yellowish plumage at some stage. In fact, perhaps surprisingly, the grey wagtail is the only one to always display some yellow. All three species share the same overall shape, slender insect-eating bill and long tails with noticeable white outer feathers. As pied wagtail is such a familiar bird, we will use this to compare to the other species. Even more elongated than pied wagtail is the grey wagtail. Grey wagtails have a similar body size but shorter legs and much longer tails, giving a very different silhouette. Grey wagtails are usually, but not always, found near flowing water and their year-round residents. They're found across the whole of Britain and Ireland but they move down from the highest mountains in winter. They can be found on slower water or even lakesides at times and even in urban areas where they will perch on rooftops near to water. In all plumages, even juveniles, there is a bright yellow undertale. Overall, the birds are grey above and paler below, with increasing amounts of yellow below depending on whether it is a young bird, an adult female or an adult summer male, which are lemon yellow below. In addition, adult males and most females have black or dark throats in the breeding season as well. If you see a wagtail with yellow on it in the winter, it is almost certainly a grey wagtail. Yellow wagtails are summer visitors, with most arriving through April and virtually all having left by mid-October. If grey wagtail is more elongated than pied wagtail, the opposite holds true for yellow wagtail. It is less long-tailed than either of the others, having a body plan more like a pippet than a wagtail, although it still pumps its tail up and down. They are more restricted in distribution, being mostly found in central and eastern England. There are small numbers in the Welsh marshes and a few around the Scottish border. It is a passage migrant to Ireland, having become extinct there as a breeder. It is generally scarce throughout its range, but is most likely to be found in damp grassland and in eastern England in arable crops. The spring male is a stunningly yellow bird, bright yellow beneath and with olive green shading on the back, back of the head and wings and rump. There is never a dark throat. The female is more washed out, with a yellow flush beneath and the same olive tones above. Juveniles and winter birds are duller still, but keeping the olivey grey upper parts, with most showing the only yellow as a slight lemony flush on the undertails. The juveniles often also show a characteristic dark necklace on the throat. Some young birds, possibly females, lack any yellow or olive colour at all, being grey above and white below. It is then that structure and habitat should help, although some birds may prove challenging to identify. Call could well help here. Yellow wagtail has a distinctive seep or see-eep call that is uttered on the ground and in flight. It is worth learning this call, as it will often alert you to the presence of a yellow wagtail nearby. It is also worth remembering that very young pied wagtails can, on occasion, display surprisingly yellow-infused plumage, especially around their faces and throats. The habitat and proximity to adult pied wagtails should help the ID here. Along with their common call, an expressive and explosive often written and remembered as Yellow wagtails are extraordinarily complex in their plumages across their world distribution. The familiar yellow wagtail of the UK and Ireland is almost endemic, occurring elsewhere only around the near continent. The next race, geographically, is known as the blue-headed wagtail, and sometimes these overshoot in spring and autumn on migration. Males are fairly easy to spot, having blue-grey heads and a strong white eye-stripe. Some females may also be identifiable in the spring, with a fainter shadow of these markings. On very rare occasions, some blue-headed wagtails have stayed to breed, usually paired with a local yellow, yellow wagtail. Other races turn up very rarely, but are always worth looking out for during passage. Females, particularly in the autumn, are frequently not identifiable from local yellow wagtails, however.