On Sunday 25th April while walking his local patch at the Verne near Portland, Charles Richards located an odd Chiffchaff singing at the bottom of the densely vegetated steep hillside under the Verne Cliffs about 200 yards beyond the Portland Naval Cemetery. It was the loud and distinctive song which had attracted his attention and after several attempts he managed good views but left the site believing that it was just a Chiffchaff with an unusual song. He did not see or hear the bird during his daily visits on the 26th and 27th April.
On Wednesday 28th he heard and saw the Chiffchaff singing again in the same place and the distinctive song convinced him to seek other opinions. He telephoned Martin Cade at Portland Observatory and after discussions the news was released of a ‘possible Iberian Chiffchaff’. With there still being some uncertainty and while I wasn’t sure of the actual taxonomic status of Iberian Chiffchaff I decided not to go immediately. In the end, however, Martin Cade, Graham Wallbridge and others visited the site and were quickly convinced that they were watching an Iberian Chiffchaff and confirmed news was released that evening. The pager also stated that Iberian Chiffchaff had been split as a separate species by BOU in January 1998. I decided that if the bird was still present the next morning then I would go after my 10am appointment.
I arrived at my appointment in Downton at 10am with positive news of the bird already on the pager. I was on my way again by 10:45am and I made it from the Wiltshire village to Portland in around 1½ hours. I stepped out of the car on the slopes above the Naval Cemetery at around 12:15pm, there were already a good number of cars parked along the roadside. I made my way down the path which ran alongside the edge of the Verne housing estate, past the Naval Cemetery and towards the roost site for the Long-eared Owls.
Before I had even joined the other birders I could hear the loud and distinctive song which I assumed belonged to the Iberian Chiffchaff.
I joined the group and it was clear that they were watching the bird that I had heard singing. As expected the bird looked just like a normal Chiffchaff although the upperparts, throat and breast were perhaps a brighter yellow.
Unlike our Chiffchaff the song seemed to be on the same pitch and finished with a final faster rattle. I watched the bird for an hour and completed some brief sketches before heading back to work.
As well as the slight plumage differences and the clearly different song there are differences in the wing formula and this was confirmed when Martin Cade, after several failed attempts, managed to trap the bird. As its name suggests the Iberian Chiffchaff breeds in Spain and Portugal where the hybrid zone is narrow and stable, DNA evidence also suggests a clear taxonomic difference with Iberian Chiffchaff believed to be the oldest chain in the Chiffchaff complex.
This became the 3rd record of Iberian Chiffchaff in Britain after a one day bird in London in June ’72 and another on the Scillies in April/May ’92. Being the first truly twitchable in Britain the Verne bird triggered a major twitch with perhaps 4,000 birders visiting the site before the bird was last seen 10 weeks later on 8th July.
Another Iberian Chiffchaff was found two weeks later at Start Point, Devon.