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20 May 2009

Icterine or Melodious?

Looks like the Great Orme warbler is causing some debate with some observors questioning its true identity. In the field the whole jizz of the bird shouted 'Iccie' but questions are being asked over the primary projection. Svenson shows there is a wide range in the wing length of Icterine Warbler and the smallest is only 2 mm longer than the largest Melodious. Easy enough to see from the comfort of an arm chair..............................

BWP suggests lenght of exposed primaries should be greater than 50% length of exposed tertials. Running the ruler over the Great Orme bird and taking into account the drooped wing so measuring the tertials rather than the exposed secondaries you get the following:

Interesting?

Melodious warblers can show pale wing panels but rarely as extensive as this bird . The dark centred pale fringed tertials are also good for Icterine as are the pale fringes to the greater coverts.

A very educational bird and one who's identity is not as clear cut as it first seemed.

4 comments :

Jason said...

Good job you got a good set of picks, or it may well have been left as it was in the field.

PeteK said...

Hi Phil.
I`ve only just had the opportunity to see all of the shots of this bird, which I`m sure is a Melodious Warbler.there are some good side on shots which show the primary extension/tertial ratio well.The pale wing panel which is oft-quoted as a certain Icterine feature is frequently present on Melodious..indeed the Melody I saw in Lancs in June 2008 had an obvious wing panel and of course was the cause of much initial confusion over its ID.Also the overall colour and rather rounded head shape, the latter a jizz feature which I always get from Melodious, seem good.
As I didnt see the bird I`m only commenting from pics seen.Just glad I`ve seen both in the NW( the Icky at Seaforth in 1992 being a particular favourite)
Surely the Wirral is due a `biggy` this Spring!!

cheers,Pete

Jane Turner said...

I think that the most telling thing wrt wing length is the fact that you can see an upper tail covert poking out beyond the wing tip

Phil Woollen. said...

An interesting bird! If it weren't for the pics I don't think anyone would have questioned its I.D. Its jizz shouted Icterine. Jane - see what you mean about the tail coverts but initially we thought that was the tip of the longest primary as they're symetrical on both sides and look just like primary tips. Still a N W first for me though.......................