The Iberian Chiffchaff (Phylloscopus ibericus), was elevated to full species level and administrated to the British List under category A by the BOU in 1999; by the end of 2015 the BBRC had 48 accepted records of Iberian Chiffchaff with 2015 also witnessing the first documented breeding of Iberian Chiffchaff in the UK taking place at an undisclosed site on the Gower Peninsula where 7 young were produced by two pure ibericus birds. In my home of Wirral & Cheshire only a single a record of Iberian Chiffchaff has been formly accepted by the BBRC which involved a singing male at Dibbinsdale NR from April 29th to May 20th 2004; a bird that was thoroughly photographed and multiple sound recordings were made ensuring its acceptance.
It’s been 13 years since Wirral & Cheshire’s first Iberian Chiffchaff had been discovered and throughout the spring of 2017 an unprecedented influx of Iberian Chiffchaffs arrived in the UK which exceeded 15 individuals, unfortunately none of which turned up in Wirral & Cheshire. What was interesting about this years large influx was not only the sheer number we were witnessing, but also the fact that it wasn’t just pure ibericus that were turning up on our shores, but as you’d might expected hybrids between ibericus & collybita (Common Chiffchaff), which as one might expect has caused confusion. When a bird turned up in Molesey Heath, Surry this year for several days it was believed to be the real deal with many folk venturing to see the bird, however it was only a matter of days till the identification of the bird was put down to either a hybrid or infact a collybita just being a pain as they have habit of doing.
Both ibericus & collybita belong to a family of old warbler called Phylloscopus of which 16 species from this family have been record in the UK: Common Chiffchaff (including race tristis), Iberian Chiffchaff, Willow Warbler, Wood Warbler, Western & Eastern Bonelli’s Warbler, Dusky Warbler, Radde’s Warbler, Pallas’s Warbler, Yellow-browed Warbler, Hume’s Warbler, Greenish Warbler, Arctic Warbler, Green Warbler, Eastern Crowned Warbler & Pale-legged/Sakhalin Leaf Warbler. This family of warblers as with all have a notorious reputation for not being the most straight forward of birds to ID with the calls & plumages of several of the species mentioned overlapping and intergrading into one another to the point were only analyses of the DNA can be used to identify them.
On the 31st of May an ibericus candidate was located on the outskirts of Delamere Forest in Cheshire near the town of Kelsall; there was as predicted a singing male however it wasn’t until the late afternoon that the bird was viewed by many as a genuine ibericus. I would go into the morphology of ibericus however a lot can be said, so if you’d be interested in taking a look at ibericus identification then back in 2008 the brilliant folk at British Birds put together this paper here.
When I arrived at the site after a pleasant walk through the picturistic Cheshire countryside where Wood Warbler, Common Quail & Eurasian Hobby were picked up, it didn’t take too long for the unmistakable “djup djup djup wheep wheep chittichittichittichitta” song of a typical Iberian Chiffchaff to start blasting through the dense vegetation along with that of the “chip-chap-chiff-chap-chap-chiff-chee“, melody of the Common Chiffchaff. The bird was sounding in song very much like that of a pure ibericus bird, yet reports were coming through from various observers that bursts of collybita/ibericus/collybita/ibericus where coming through with at points the bird going into raw collybita song.
I’m far from an expert on Iberian Chiffchaffs and before the trip to see this bird I had done no gening up, but it was when the bird started doing this alternating from the classic ibericus “djup djup djup wheep wheep chittichittichittichitta” into a combination of “djup, djup, djup, chap-chiff-chap-chiff” & “chip-chap-chiff-chap-chap-chiff-chee”, that I did start to wonder could this be some form of hybrid ? Yes in terms of morphology the bird ticked all the boxes for a text book bird with a white belly, yellow throat, lemon rump, yellow vent, weak eye-ring, yellow supercilium & a tinge of yellow to the base of bill etc.
Arriving home later that day I mentioned this to a few folk who’d had vast more experience in ibericus than I had and it was comforting to hear from various sources that ibericus do infact mix song on with this exact from the British Birds paper on Iberian Chiffchaff supporting this “the conflict song of Iberian Chiffchaff, given in response to, for example, a rival male, is very similar to the familiar ‘chiff-chaff-chiff-chaff ’ of Common Chiffchaff. The definition of ‘mixed singer’ is reserved for those birds that use song elements characteristic of both Iberian and Common Chiffchaff within a single advertising song.” So after having my hopes of this being an accepted bird then dropped due to myself having a lack of knowledge & experience in this vagrant warbler (I find best & only way to learn is from mistakes), it seems that this individual has every chance of being accepted making it Wirral & Cheshire’s 2nd ever Iberian Chiffchaff.
Thanks for reading,