This photo shows the emargination on the 3rd and 4th primary feathers, P3 and P4. Emargination is the narrowing of the
outer web of the feather towards the tip of the wing. On Eurasian Reed & Marsh Warblers this emargination should normally only be
present on P3. The photo also shows P2 as being distinctly shorter than P3 whereas on Eurasian Reed and Marsh Warblers
these should be almost the same length.
NOTE: P1 is greatly reduced or vestigial in most passerines, so the primary count begins at P2 on this photo.
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Chris - thanks for comments - very great photos, and well done in taking the time to show and explain the complexities of the wing formula, there are a lot of birders that can learn a thing or two from your blog. It's amazing how things have moved on with bird id, it wasn't that long ago a Blyth's Reed in the field would not even have been considered by the old BBRC now its a local rarity and the the quality of photographs mean we can see and prove tiny details like the emarginated primaries. If the camera isn't already , it is fast becoming an essential part of a birders kit. I videoed the bird too, not for the poor footage I obtained but to capture the call which the camera did very well.
ReplyDeleteYour blog was so good I think I'll copy itall and send it to the DBRC to assess - As you're on the committee I expect it to fly through... Its gone today so your visit was perfectly timed.
Cheers
Mike
Many thanks Mike - I will maybe put a link on the Devon Birds website if you think it useful. As you say, Blyth's Reed Warbler was historically a no go bird unless trapped! Agree cameras are now essential these days. Anyway, thanks again for finding it in the first place! - I resisted it for 2 days hoping to find something this end as I can clearly see Berry Head, but it never quite works like that! Glad I ventured over as a great bird to learn from and always worth seeing. Sorry I missed you.
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