I have written a piece on my blog about the identification of Iberian Chiffchaff by song. I have also included the called of both Chiffchaff and Willow Warbler, which in the UK look very similar and are the possible (common) confusion species.
Here is the piece: http://andrewkinghorn.blogspot.com/2010/07/iberian-chiffchaff-have-you-heard-one.html
Hope this is of some use to people.
I Have Moved
6 years ago