John Martin very kindly emailed me his image of the Church Cove Phyllosc (see top - taken on Thursday afternoon in reasonable light conditions) whilst Mark Newsome emailed some Bright Green Warbler images taken in Goa (India) on 12 November 2008 for comparison.
This is a summary of an identification paper published by J.S.M. Albrecht in Sandgrouse 4: 69-75 entitled ''Some notes on the identification, song and habitat of the Green Warbler in the western Black Sea coastlands of Turkey''
Albrecht found that in 1972-1978 at least, Bright-Green Warbler occurred in western Turkey some 700 kms further west of previously reported locations. For example, in May-June 1978, at least four singing males were seen in mixed forest at about 1,500 m in the western Pontic Mountains south of Duzce, whilst Mark Beaman and Iain Robertson saw at least six singing males in this area and a further six in Beech and other mixed woodland on the slopes above the road between Bolu and Abant Golu, 30 kms from Duzce.
Most interesting with regards to this population was that they did not conform to the general appearance of birds commonly encountered in the Sivri Kaya region and at Sumela Monastery. In the Duzce birds, the upper parts (that is the crown, nape, back and upperwing surfaces) were grey-green, with a single pale wing bar on the greater coverts. The supercilium, throat and breast were pale yellow to greyish-white depending on the light conditions. The remainder of the underparts were pale. The bill was horn and the gape yellow and the legs were dark. In general the birds were neither very yellow nor very green and resembled more the colour of Greenish Warbler than of Green Warbler but Mark Beaman did note one very yellow bird within the singing population.
The vocalisations of Green Warbler are hard to describe but the 1978 Duzce birds uttered a di-syllabic ''Tss-eurp'' contact note whilst the somewhat Wren-like song was transcribed ''chewee chewee chewee chewee chui chui chui chui'' - identical to that of birds in the Sivri Kaya firwoods.
British Museum skins of Two-barred Greenish Warbler are fairly distinct having a greyish-olive back and off-white underparts with very little or no yellow. Green and Greenish Warblers have olive green upperparts with Green Warbler having a yellow green and Greenish Warbler having a greyish-green back on average but there is some overlap. Similarly, Green Warbler generally has more yellow than Greenish on the breast and belly but there is considerable overlap. In conclusion, the difference between the museum skins of Green and Greenish Warblers is far less clear cut than what the literature often states.
Subsequent studies of Green Warblers in Eastern Turkey, contrary to much of what is published, has proven that many Green Warblers are very dull and look very much like Greenish Warblers and often possess very little yellow on the underparts (Beaman, Porter, Kitson, Evans, et al). A similar situation exists in the Caucasus Mountains in Armenia and Georgia where many of the singing Green Warblers in spring are dull with a faint wash of yellow which closely resembles Greenish Warbler. But, while the plumage is very similar, the song is very different from that of Greenish Warbler in the Moscow area (Steve Madge). In southern India in spring, Richard Grimmett found a complete range from obvious Green through some birds that were impossible to identify.