By Yoav Perlman
This stunning (putative) Stejneger’s Stonechat was ringed at the migration hotspot of Falsterbo Bird Observatory in southern Sweden on September 20th. The bird was caught in the reedbed area north of Falsterbo lighthouse. Björn Malmhagen from Falsterbo participated in the recent and hugely successful Spurn Migfest and had a great time it seems. Björn was also involved in the identification of a stonechat at Spurn a few days ago, first thought to be stejneger’s but later identified as European Stonechat. It’s great to see the partnership formed between Spurn Bird Observatory, Falsterbo BO and Cape May BO.
Björn sent me these educational images, comparing the Falsterbo bird, 1cy female, with an almost identical bird he had ringed in China exactly a year earlier. Incredible. Feathers of the Falsterbo bird were sent for DNA analysis by Martin Stervander at Lund University, Sweden. So hopefully ID will be confirmed soon.
Of the maurus group, stejnegeri is the eastermost form, and not the easiest to identify, especially from European Stonechat. But in recent years more focus has been given to this taxon after several western European records (see previous posts on Birding Frontiers here and here).
In these excellent composite images by Björn, the key features can be seen. This is what Björn wrote to me about his impression of the bird in the field: “The bird gave an overall dark impression with a deep rusty rump and uppertail-coverts lacking any dark markings. The underpart was light orange – in colours closest to a western bird – in contrast to a whitish throat.”
The strong bill is also evident here. Width of bill of the Falsterbo bird at the proximal edge of the nostrils was measured to 5.2 mm which, according to Svensson (1992), places this bird outside the range of maurus (4.7–5.7 mm in stejnegeri, compared to 4.0–4.9 mm in maurus). Compared to other Siberian Stonechats, primary projection is not that long – wing measurement was 69 mm.
The pattern of rump and uppertail coverts is crucial for ID. Note the richly toned rump, unlike that buff-whitish rump of other maurus. Also, note the dark centers to longest uppertail coverts – typical for stejnegeri (more than half of individuals were found to have such a pattern – see another excellent article by Magnus Hellström and Gabriel Norevik in BB (2014)):
Many thanks to Björn and his brilliant team from Falsterbo BO for sharing this with us.