By Yoav Perlman
Eastern Yellow Wagtail Motacilla (flava) tschutschensis is the eastern counterpart of Western Yellow Wagtail. It is divided into two main groups – ‘blue-headed’ with supercilium (tschutschensis and taivana), and ‘grey/black-headed’ without supercilium (plexa and macronyx).
This is another taxon that seems to get identified in Western Europe in increasing frequency. There are three accepted records in the UK: Colyton, Devon in December 2010 bird that was DNA’d, featured in the definitive article by Sander Bot (2014) et al. (Dutch Birding 36: 295-311), Outer Skerries (Shetland) in 2011, and an old specimen from Fair Isle 1909. But there are some further recent strong candidates in the UK that ticked all (or most) boxes. Some have featured on Birding Frontiers before – for example here and here. Looking back through the archives of Birding Frontiers, the learning curve is apparent – Martin really pushed the boundaries here. With the progression of knowledge, it is possible that BBRC will accept future records without DNA, based on good photos and sound recordings.
This striking individual was present in Scilly earlier this month. To my eyes and ears it is a perfect example of an Eastern Yellow Wagtail. I want to thank Nigel Hudson (BBRC secretary) who helped me obtain material for this post, and kindly shared the ‘story’ of its discovery with me:
On October 13th, while Nigel was cutting his front garden grass, a group of birders that included Mark Andrews walked past his house as they headed out from Lower Moors on St. Mary’s. To his question if there was anything about, they showed him on their camera screens photos of an odd yellow wagtail, and they mentioned Eastern Yellow Wagtail as a possibility. Nigel rushed the whole 100 m from his house to where the wagtail was, and after initial views alerted local birders. They all obtained great photos of the bird and some sound recordings during the few days it stayed in the same area – a selection is presented here.
When identifying 1st-winter Eastern Yellow Wagtails, it is necessary to exclude Citrine Wagtail and Western Yellow Wagtail, and hybrids between the two (like this possible bird). A small proportion of 1st-winter Western Yellow Wagtails can give a similar monochromatic impression; and especially in the eastern fringes of the range; in beema and lutea, 1st-winters tend to be more monochromatic, lacking or almost lacking yellow and green tones, especially females (1st-winter males are on average yellower than females). In Eastern Yellow Wagtails a high proportion of 1st-winters are very grey-and-white. Some show faint yellow tones on the mantle, undertail coverts and tertial fringes, but the Scilly bird is as cold as it gets:
Two Western Yellow Wagtails for comparison:
Eastern Yellow Wagtails are sometimes placed in the same phylogenetic clade together with Citrine Wagtail, and indeed share some morphological features.
The call of Eastern Yellow Wagtail is close to the call of Citrine Wagtail, but not quite there with regard to high pitch and rasp. Western Yellow Wagtail calls can be divided into two groups – sweet calls of western taxa (e.g. flavissima, flava) and rasping call of east European taxa (e.g. feldegg). I didn’t obtain a proper sound recording of the Scilly bird, but in this rather atmospheric video by Will Scott the diagnostic call can be heard at 0:06 (put your headphones on!).
Compared to Western Yellow, both Eastern Yellow and Citrine show more extensive white tips to greater and median coverts, creating two bolder white wingbars, and more white on tertial fringes.
Though rarely 1st-winter Citrine Wagtails show incomplete ear coverts surround, Eastern Yellow Wagtail can be readily identified by wholly or predominately dark ear coverts, narrower supercilium, and pale base to lower mandible, just about visible here in this brighter photo, where some faint yellow and green hues can be seen:
1st-winter Citrine Wagtail for comparison:
Citrine and Eastern Yellow Wagtails also share a long hind-claw, longer than in Western Yellow. So if you see a wagtail with a hind-claw as long as this it might come from the east:
Many thanks again to Nigel Hudson and Will Scott who helped me with information and contacts; and to photographers Simon Knight, Steve Young and Kris Webb – they all have stunning images of lots of cool birds, check their websites!