Near East Chiffchaffs

I got rather confused by the Chiffchaffs in Turkey and Syria. I saw the odd Chiffy around Adana which looked and sounded like the collybita that I am familiar with. In Syria the first thing I noticed about the Chiffy's was the call- a simple mournful note (tristis like?) quite unlike what I am familiar with. Yoav Perlman from Israel informs me that most of the Chiffchaffs in the region are abietinus and the unusual call which recalls tristis could represent some kind of clinal variation. Apparently there are populations of Chiffchaff which move through the near east and winter in East Africa and other populations which winter in the region. There is a lot of biometric and tonal variation and some genetic studies reveal little in the way of distinct forms.