I got down to Church Cove a bit after first light and the bird had already been found. It had been calling continually, but wasn’t when I arrived. Unfortunately those present first thing, weren’t particularly familiar with the call and were unable to say which species it was. I played my iPod (which I’d also been playing in the car on the way down) to a few present, and most people seemed to think it was closer to Greenish, but few were willing to commit with 100% certainty. I heard it call once in flight, to me it sounded more like Greenish, but hard to tell on one call. Those who’d seen it initially suggested that the bird had quite a distinctive yellow wash to the underparts, supporting Green. For the next few hours, it showed briefly at intervals up in the canopy, generally in quite poor light as it became very misty. I saw it quite well on a number of occasions – in all of the views I got, it looked very lacking in yellow, the supercilium had a hint of very pale yellow (but no more than this one) and the wing-bar (strong) looked creamy. Had I seen it without prior knowledge of it being a possible Green, I would quite happily have passed it off as being a bog-standard Greenish (obviously after eliminating Arctic). The only slight oddity was that it looked a bit drab, or dingy below. Others commented on seeing a yellow wash to the bird under certain lighting conditions, but I just didn’t get this at any time. However, the tone of the bird did seem to vary quite a lot dependant on how silhouetted it was. During the morning, I also heard it call again once, and again in my opinion it sounded a bit odd, but more like Greenish. We also gave it a bit of Rare Eastern Vagrants on the iPod and seemed to get a bit of a behavioural response from Greenish and not Green, but not really enough of one to say anything important about this. I voiced in my opinions on the appearance and call at the time and didn’t really receive any resistance, but was very mindful of the fact that others had seen it in better light before I got there. I did phone RBA though, stressing that I wasn’t 100% sure, but that I thought it was a bog-standard Greenish and as such, a drive across the country probably wouldn’t be worth it. I should also add that my field experience of this group is very limited – I’ve found 3 Greenish Warblers in Norfolk in the last three years (which I obviously grilled closely) and have seen two others, but have never seen Green or Two-barred and have never seen Greenish abroad.
The bird then disappeared for several hours. Most people stayed on, as all of us were unsatisfied with the lighting conditions under which we had seen the bird and only one or two voiced opinions on the call. Fortunately it was relocated about mid-afternoon after the mist had cleared and showed well (or as well as a phyllosc can) for about 20 minutes, and was seen by the 30 or so birders present. It then became quite obvious the bird really didn’t have distinctive yellow wash to the underparts and the throat etc. The supercilium was indeed washed with a very pale lemon-yellow, but in my opinion, pretty standard for Greenish Warbler. The wing-bar was strong, but creamy rather than yellow-tinged and the throat and face lacked a distinctive yellow wash to suggest Green (at most only a hint of pale yellow). Other observers, including one person who got it through a telescope noted that the supercilium did not meet in front of the eye, which is a pro-, but my no means definitive Green rather than Greenish feature. I missed this, but I completely believe that this was the case.
In short, I appreciate that they can be very tricky to identify at times, but to me the real question is, was there anything to suggest it was a Green rather than Greenish? I appreciate that both would be rare in Cornwall, but personally I just didn’t see anything at any point that made me think anything other than Greenish. I would welcome comments from anybody else who saw it today, particularly if you heard it (I missed it both times when it was calling continually). Also, if anybody with field experience from Asia has any thoughts I would be interested to hear them.