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Taxonomic Decisions

March 26, 2012

In the “Eastern Black Redstart in East Kent” UK400 article George said “it seems logical to treat Eastern Black Redstart as a separate species”. Then George got stick from Alex Lees on this decision and other UK400 taxonomic decisions. We had to chuckle at Alex’s response which is below.

After the Alex Lees bash George did a U turn and said to Alex “If it puts your mind at rest, I have not announced a split of Eastern Black Redstart yet, just intimated it, and I shall confer with my advisors over the next two months“. It is currently not on the UK400 list as a separate species.

Apparently George had talked to Lars Svensson about the eastern Black Red! We do not know if this really did happen but in the past there have been occasions where George has claimed that he had spoken to an “advisor” but the “advisor” knew nothing about it. Some advisors did not know that they were a UK400 advisor! George has admitted in the past that the final decision is his alone and not the advisors e.g. “the ultimate decision is mine”. He has also said that he has gone against the advisors decision. Sounds more like a one man band with no committee especially when he said on Surfbirds on assessing a bird ID record “Being a one-man band, it is clear that I am going to upset people with my decisions”

The original Surfbirds post can be found on

George’s comments are in bold italics. By the way we are not too keen on having 5 species of Redpoll on the UK400 list.

Hi Lee

We seem to now be having two parallel conversations (the other one now incomplete as my email wasn’t delivered) but am quite happy to continue the debate here….

Quote Originally Posted by LeeEvans View Post
Alex I discussed the Black Redstarts with Lars Svensson, who is currently studying them in detail with Lars Jonsson in Oman.

I don’t see how information from Oman could help with understanding the reproductive isolation of Black Redstart taxa – although multiple taxa may winter syntopically it doesn’t help with knowing what happens where the forms breed in close proximity.

Quote Originally Posted by LeeEvans View Post
His advice to me was to be consistent – and if I was to continue to follow George Sangster’s PSC recommendations and adopt many of his proposals, then Eastern Black Redstart (consisting of two forms) was easily as distinctive and physically evolved as many ‘species’ which I have already decided to ‘split’ (eg, Eastern Yellow Wagtail, Siberian Chiffchaff, Dusky Thrush, Red-throated Thrush and so forth).

Being consistent is obviously key and I am 100% PSC, a tree-based taxonomy seems the most efficient way of classifying bird biodiversity. However you consistently fail to understand what the PSC is, it isn’t ‘raise all subspecies to species level’. Ideally its have a phylogenetic tree and understand whether or not different avian lineages represent discrete evolutionary units. We have a tree-based taxonomy for the redstarts and the answer is demonstrably no for the time being.

Moreover, you aren’t consistent, for example you follow the recent proposed Eastern/Western Yellow Wagtail split (based on paraphyly) but then you also treat feldegg as a separate species. To be consistent you must lump Black-headed Wagtail….

Siberian Chiffchaff is something of an enigma within a mystery but there is data from contact zones so hopefully there will be closure on that one. Likewise there is evidence of stable hybrid zones in the thrushes so they may be BSC (semi)species. The problem with Red-throated and Black-throated Thrushes is that it may just be a single gene that makes the difference, clearly differing by a single gene doesn’t warrant species status. Given that hybrid BlackxCommon Redstarts are apparently separable from Easterns on wing formula and DNA alone then we get the idea that differences are pretty minimal.

Quote Originally Posted by LeeEvans View Post
He confirmed, as did others I consulted with, that both the songs and calls were definably different from Western birds, and we also know that both the wintering and breeding ranges do not overlap. He did warn me against classifying Middle Eastern Black Redstart, as it is not known whether it is closest to Western or Eastern Black Redstart.

I don’t want to second guess the godfather of Palearctic ornithology, but how do calls differ – frequency, pitch, interval? What are the quantitative criteria that determine species limits? What does a difference really mean for taxon recognition? Are the calls selectively neutral?

Quote Originally Posted by LeeEvans View Post
He concluded by saying that from his standing he is very conservative in his views, and is not really a ‘splitter’, but realises that current trends are to move more in this direction in relation to bird forms and in many cases, it actually benefits birds and provides a platform for protection.

This is especially true where I work, watch this space….

Quote Originally Posted by LeeEvans View Post
In any event, both the CDSNA and I have to be consistent, and by accepting the likes of peripheral forms such as Green-winged Teal and Hooded Crow as species, I really cannot disown this highly distinctive Black Redstart……….

Yes, BUT, Hooded Crows = semispecies, we can experimentally observe what happens when the two forms are in contact, they form a stable hybrid zone, they aren’t ‘peripheral species’ any more than Collared and Pied Flys are. The highly allopatric teal situation is completely different and the inferred phylogenies very puzzling, I doubt we’ve heard the last word on that one…

Did you know that there is some evidence for assortative mating between dark and pale morph Arctic Skuas?



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