Tuesday, 8 June 2010

Shetland’s first Iberian Chiffchaff

Brothers Stef and Ash McElwee have been annual visitors in recent years, coming to Unst during the English spring half-term holiday. They have found a good many records during the previous years, but this year they managed to add a species to the Shetland List. Here is their account of the find.

 Photo by Stef McElwee

Sometimes in birding, lightning can and does strike twice. This was certainly the case in the finding of Britain’s most northerly record of Iberian Chiffchaff at Halligarth plantation, Unst. Both of the finders of this bird have previously found or been in on the find of an Iberian Chiffchaff in the UK, at Stiffkey Norfolk this year (AIM) and at Newbiggin Northumberland in 2004 (SJM). When a strange yet familiar song burst from the plantation on the morning of Friday 5th June it is fair to say that both observers were primed for the event!

Birding on Unst in the preceeding week had been hard work due to very small numbers of common migrants, yet rewarding due to quality birds being found such as Bluethroat and Shetland’s third Black Stork. With this in mind, we continued to work the sites on north Unst on Friday.

At mid-day, we arrived at Halligarth plantation to be greeted by a Willow Warbler in full song. Ash also detected another bird singing more distantly in the plantation.  On arriving level with the derelict house both observers heard a snatch of the song again, “wheet wheet, tif tif, tif".  Although jumbled and not classic in phrase, both observers looked at one another and said “ I know what this is going to be” and calmly walked into the wood with Ash’s Remembird sound recorder at the ready. 
True to form, the bird began to sing loudly, and in prolonged bursts from the canopy. “Tif, Tif, Wheet, Wheet, Wheet, De De De, De De De" is an attempt to transcribe the persistent and ringing song flowing out of the canopy above our heads! It is difficult to describe the surreal experience of recognizing a Shetland first without seeing the bird. Stef looked at Ash and said “come on bird, please call”, to which it duly did, a piercing downward carrying "peeoo", similar in pitch to a Siberian Chiffchaff but with an obvious downward carrying note at the end.  Knowing this call note is pretty much diagnostic of Iberian Chiffchaff we were faced with the bizarre dilemma of needing to phone out a Shetland first without having seen the bird! Knowing the importance of the record we decided we had better see it to check it actually looked like an Iberian Chiffchaff!

Thankfully it did! Ash had good views of the characteristic spikey bill with an orangey pale lower mandible, the whitish underparts with yellowy wash to the fore supercilium, throat and upper breast and the mossy green upperparts and longish looking primary projection. Enough was enough and the news was phoned out to the Unst birding population and Roger Riddington. Paul Harvey and Rory Tallack arrived soon after (Paul was working on Unst that day) and they were able to confirm and enjoy the bird already described. The bird continued to show well for periods for the rest of the day and could easily be located in the plantation by the clear ringing call already described. The bird sang strongly for the remainder of the morning but was much less vocal on a cloudy afternoon. There was no sign of the bird the following day.


A very distinctive Phyllosc with a bit of Wood, Bonelli's and Willow Warbler thrown into a Chiffchaff’s clothing.  This bird was on plumage and structure quite similar to a Willow Warbler and I wonder if not singing or calling how many birders would simply misidentify one as such! Certainly the strongish supercilium and longer-looking primary projection would hint at this species. The pattern and combination of white, yellow and green is not dis-similar to a poorly marked female Wood Warbler.

Head: this bird showed a strongish supercilium, notably yellowish in the fore area, with the super extending to the rear of the ear coverts. Supercilium aside, this species has a very characteristic open faced appearance due to the relatively plain and unmarked ear coverts. The bird showed a weak eye ring most notable around the lower half of the eye. This bird showed the bill structure that appears quite distinctive of this species. Best described as longish / spikey with an obvious pale orangey lower mandible.

Upperparts:  the crown, mantle, scaps and coverts were a warmish green colour with notable greenish fringes to the secondaries and the tail feathers. The primary projection was longer than a typical Chiffchaff, approaching Willow Warbler in projection. This long winged appearance was very noticeable in the field and added to its particular jizz.

Underparts:  bird had quite cleanish white underparts with a subtle yellowish wash to the throat and upper breast. The undertail coverts appeared to have a yellowish wash but this may have been a trick of the light as the bird was viewed above observers heads.

Bare Parts: bill already described. There was much debate as to the leg colour. I thought that the bird had quite pale orangey pink legs but other observers described them as much darker than this. It will be interesting to analyse images to assess this.

Song:  Ash has recorded and assessed the sonograms of this bird and has described both the song and calls as classic.  I have already described the typical song above but it should be noted that this bird, particularly in strong bursts would produce a variety of different versions. It would sometimes sing “tif tif wheet wheet wheet tif” and would miss the characteristic third part rattle from the end of the song.  This is fairly typical of British vagrants, the Newbiggin bird certainly did this throughout its stay.  The gap between the "De De De" notes also varied, sometimes issued as a rapid trill, other times with bigger gaps between notes.

 Sonagrams of song (upper) and call (lower) by Ash McElwee

(both go to external links - click 'back' to return to this page)

In conclusion, the subtle plumage features, structural differences, characteristic song and diagnostic call make Iberian Chiffchaff a relatively straight forward identification if care is taken with the exact components of the song and the diagnostic call is noted. We expect it will not be too long before Shetland birders can look forward to another of these superb leaf warblers.

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