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|Wednesday 16th May 2012, 20:00||#1|
Join Date: Jun 2007
Rare Bird Alert weekly round-up: 09 - 15 May 2012
From the RBA weekly round-up: 09 - 15 May 2012
The weeks highlights:
The Flamborough Ficedula Flycatcher puzzle is resolved….
Scottish Greater Yellowlegs to-ing & fro-ing in Aberdeenshire
Significant arrival of Red-rumped Swallows continues….
Another week of “mixed bag weather” which didn’t seem to hold too much back….a moist, rather warm (certainly compared to recent days) push of air from the southwest at the start of the round-up period seemed to assist a few overshoots and as the seven days ticked away there were any number of nice mid-May birds on offer.
It must be said that the Grade A, 5-Star mega was notable by its absence but that’s the way it is sometimes, even in May….but a quick glance through this week’s list provided any number of extremely tidy scarcities and rarities to play with.
As the week drew to a close, there was a whole bunch of wobbly westerly (or north-westerly) winds to deal with across almost the whole of the country ~ but May being what it is, the surprise package will be just a binocular scan away…
So, what of this week? Well, first and foremost, the test results are in and the answer surprised many…..
Hands up at the back who thought that the F3 (the Flamborough Ficedula flycatcher) would turn out to be a Pied Flycatcher? No, not many…..and even those who had gone down the Pied Flycatcher route had preceded those two words with “Iberian” (could they though, in the long run, still be proved right…?)
The work undertaken in the labs in north-east Scotland saw Dr. Martin Collinson pronounce on Saturday that, cat amongst the pigeons time, the F3 was a Pied Flycatcher. Who better to summarise the work undertaken, and its findings, than Dr. Collinson himself…..
“Genetically, the four Western Palearctic black-and-white Ficedula species are all quite distinct from each other, and the feathers from the Flamborough bird provided a potentially foolproof way of deciding whether it was an Atlas Flycatcher. At the mitochondrial DNA level, the Pied, Atlas, Semi-collared and Collared Flycatchers show about 2.5-3.5% divergence in their sequences. On the first round of analysis we successfully sequenced 3000 base pairs of mitochondrial DNA from 4 separate genes and the Flamborough bird was identical, or almost identical (0 to about ~0.1% divergence) to nominate Pied Flycatchers. While we can occasionally make small mistakes in reading long stretches of DNA sequence, there is no way to make enough mistakes on that scale to turn Atlas Flycatcher DNA into another species. For example for 991 bases of the cytb gene, the Flamborough bird was identical to, or only 1 base pair different from, nominate Pied Flycatchers but 29-35 bases different from Atlas, Collared and Semi-collared Flycatchers. Whatever the Flamborough bird was, it wasn’t an Atlas Fly.
Another initial possibility was that the bird was a Collared x Pied Fly hybrid. The mitochondrial DNA comes down the female line, so to that point we only knew that its mum was a Pied Fly. To find out what its dad was we needed to sequence nuclear DNA, which would be a mixture of genes from both parents. Fixed differences between Collared and Pied Flycatcher genes have been defined previously by other labs – e.g. at position 315 of the RHO-1 gene, Collared Flycatchers always have a ‘G’ and Pied Flycatchers always have an ‘A’. If the bird was a hybrid, at that point the sequencing machine would get confused as an ‘A’ and a ‘G’ went through the reader together. For the Flamborough bird, the sequence was only ‘A’ – its dad was a Pied Flycatcher too.
Iberian Pied Flycatcher was the final possibility. Genetically, the iberiae subspecies is very close to nominate birds but appears to be, just about, reliably distinguishable. At the cytb gene, the Flamborough Flycatcher was 4 bases different from Iberian Pied Fly sequence, and similarly different at other genes. There wasn’t a lot in it, but it seems as though it was not an Iberian bird either.
Conclusion? Pied Fly. More cautiously, either the bird really was ‘just’ an aberrant, or extreme, Pied Flycatcher showing plumage features more consistent with Atlas or Iberian Pied Flycatcher, or there is something even more weird going on – maybe a second or third generation hybrid, or with some Iberian ancestry that we have not picked up on the first round of analysis. We will continue to work on this bird. It seems to have made the certain field identification of vagrant black-and-white Ficedulas a more daunting task.”
A massive thanks to Martin for taking the time to lay out the whys and wherefores of the work undertaken to resolve the puzzle and, as he touches on at the end of his final paragraph, as news of the bird’s lineage is absorbed, its now time to take stock, ask more questions and wonder what it means for the safe identification of Atlas Flycatchers away from its normal breeding range. If a Pied Flycatcher can really look like this, how safe are some (all?) of the records of Atlas Flycatcher from Europe now?
Given the remarkable appearance of the bird (and what it was meant to sound like) there remains a school of thought that still suggests that the potential for the F3 to still be an Iberian Pied Flycatcher remains (despite the initial findings from Aberdeen). For those who feel that there is still mileage along the Iberian road, their first step is to find a nominate hypoleuca that mirrors the plumage of the Flamborough bird. Google images may be in for a busy time….
The bird politely remained on station for the start of this round-up period, last seen on 10th, but saved his blushes by departing before the pronouncement was made as to his parentage. Many birders may also be questioning the bird’s parentage, but some may choose a rather more Anglo-Saxon approach to that matter, having gambled time and money to see the bird (such are the occasional risks for the insurance lister).
The positives are endless though ~ much has been learned over the course of the bird’s double-figure day stay and it was an entertaining exercise in extrapolating what you wanted to from the endless posts on the topic across the assorted online debating chambers. All that newly acquired knowledge can be used to further the identification processes of black-and-white flycatchers.
No one looks daft, no one has “lost face” in the last two weeks ~ this superb-looking bird has pushed things along and all those parties involved (however disappointed they may be) have played their part in a sometimes-riveting discussion and identification puzzle. The fact that resolution came only in the lab gave things an air of uncertainty, mystery and no little excitement.
While all this was going on, there was very little else happening by way of new “big birds”. In fact, there weren’t any….! The only other star turn this week was the long-lingering Greater Yellowlegs that was seen again on the Ythan Estuary on 12th (having last been reported, at the same site, on 5th) before heading back up to the Loch of Strathbeg on 14th. It just doesn’t seem to know what to do with itself….its UK “staycation” could be longer than predicted.
Rarely do Red-rumped Swallows make the headlines ~ but the continued push of birds in to the country during the past few days is worth highlighting. Last week around 20 birds were recorded, this week there’s been another leap in numbers, at least 31 birds seen (the total could actually be closer to 35 or more depending on how some counties records are dealt with).
Top of the heap was Scilly ~ four birds seen amongst the hirundine flock over Porth Hellick on the evening of 12th and local opinion suggested that thoughts of as many as six individuals around St. Mary’s that day was not unreasonable.
Up to four birds were seen in East Yorkshire (including three fly-throughs over Spurn) and four were also seen in Norfolk (with two over Blakeney Freshmarsh on 10th). Four more were in Suffolk, with two for Minsmere on 12th, while Lincolnshire scored three on 11th (including two at Frampton with another there on 15th), Northumberland had three on 12th (including two at Lynemouth) while Kent and Cambridgeshire also rattled in three singles during the week. Elsewhere singles were found in Cornwall, North Yorkshire, Aberdeenshire and Wexford.
Much more in the full online round-up including;
- Significant arrival of Red-rumped Swallows continues
- Scottish Greater Yellowlegs to-ing & fro-ing in Aberdeenshire
- Photos of a male and female Kentish Plover in Cornwall, Snowy Owl on North Uist, adult Pomarine Skua at Chew Valley, a Red-spotted Bluethroat in Hartlepool which seemed desperate to be photographed and boy was it!
Plus much more...
>>> Read the rest of the round-up here <<<
And remember the fully illustrated RBA weekly round-ups are completely free
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