It's turning into quite an 'American' autumn in Britain and Ireland this year. Following the news breaking of the Irish Little Blue Heron a few days earlier, on 8th October Cornish birder Kester Wilson found Britain's first ever Empidonax flycatcher. It had been long-predicted that at least one of this genus would finally make it to the British Isles; Acadian, Alder and Least Flycatchers all feature on the Western Palearctic list. However, the exhilaration of finding a first for Britain must have been somewhat tempered by the fact that it wasn't at all clear that it would be possible to identify the bird to a definite species.
The flycatcher was soon named confidently as either Alder or Willow Flycatcher. These two used to be lumped as a single species - Traill's Flycatcher - and many American birders still use this term, as the species are essentially indistinguishable in the field except sometimes by voice. Somewhat unfortunately, they don't tend to be very vocal on autumn migration, so it looked a very real possibility that this bird could disappear without anyone ever knowing for sure what it was.
Therefore, permission was sought for local ringers to catch the bird, to obtain measurements. Although there is some overlap in measurements between the two species, this can help the identification process substantially. Permission was granted on 9th October and the bird was caught and subsequently announced to be a first-winter Alder Flycatcher.
We have therefore added Alder Flycatcher as a provisional species to BUBO Listing for people to add to their British (or British & Irish) lists. As ever, we reserve the right to remove this species should further information come to light that casts doubt on the validity of this identication (which is perhaps more likely with this record than with any of the other provisional 'firsts' we've added).
Thanks to John Martin and Matthew Deans for their photos.