DNA analysis of the Lesser Whitethroat

During it’s stay at Birling Gap, I got a little bit obsessed with this Lesser Whitethroat. A determined effort was made to obtain sample material to allow for DNA analysis. Unfortunately for the bird, it had a very swollen hind toe which at one point bled on to some mallow. I retrieved the twig and posted it to Dr Martin Collinson at Aberdeen University. The results returned confirmed the bird was “unambiguously a blythi” and “clearly diverged from all other taxa of Lesser Whitethroat” which was satisfying.

5T6A0073

blythi Lesser Whitethroat.

Presently there are two recognised races of “eastern” Lesser Whitethroat to have been recorded in the UK, blythi halimondendri. Using current literature I felt it most likely this bird was blythi. Perhaps in danger of over simplifying things, it seems possible to identify and separate these two types in the field. Although they share similar features, this birds’ structure was more blythi, especially in regard to the primary projection. In terms of vocalisations, I only ever heard it “Tak” reminiscent of the call one would expect from curruca. Coincidentally nearby Dungeness hosted an example of the much rarer halimondendri over the same dates. Dave Walkers in the hand photo’s of that bird clearly showed a much shorter, blunter wing. Although to add to the current complexity it’s now believed two types of halimondendri have occurred in the UK!

LW141 - Birling gap

Above the DNA verdict.

Although not possessing true rarity status, blythi (or Siberian Lesser Whitethroat as it is also known) is a scarce autumn migrant mainly to the northern and eastern shores of the UK. Currently considered a race of Lesser Whitethroat it may have it’s taxonomic status revised to that of a full species in the future. This bird constitutes the first Sussex record to be accompanied with confirmatory DNA. Late Lesser Whitethroats are occasionally noted in the annual Sussex bird report and it’s reasonable to suggest, from October onwards, they may refer to birds of eastern origin. I suspect Siberian Lesser Whitethroat may well be occurring almost annually in Sussex and as opinion solidifies around “in the field” ID features, it may become quite acceptable to identify these birds without the need DNA analysis.

5T6A0054

A big thank you to Martin Collinson and Thomas Shannon for their time and work. The original post for this bird can be found here.

 

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