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Saturday, 31 October 2009

GREENISH WARBLER it is - on call - but not in field characters

I, along with 250 others, made the journey down to Church Cove on The Lizard today. Both Alan Lewis and Ilya Maclean obtained good sound recordings of the bird before I arrived on site at 0715 hours and after listening to Alan's tape, I could hear that the bird was clearly making a short, quick disyllabic note, repeated quickly in succession.

The bird was showing from the minute I arrived on site, flicking quickly through the Sycamores adjacent to the car park, often in accompaniment of a single Scandinavian Chiffchaff, two Common Chiffchaffs and occasionally a Pied Flycatcher and a YELLOW-BROWED WARBLER.

I must stress that the bird met all of my expectations and after obtaining numerous good views, both with 'bins and prolonged views in the 'scope, both high in the canopy and low down in the vegetation, I became convinced that the bird was a BRIGHT-GREEN WARBLER. Several photographers were able to get good images of the bird as it fed, including both Jim Lawrence and Steve Rogers, allowing us to carefully assess the bird's features. Ian Wilson (Kester's father) also showed me what he had managed to gather on film over a number of days visiting the site.

I was most overawed by the bird's structure, with a somewhat long primary and a thick-set, long bill, distinctly yellowish-orange on the lower mandible. It gave me the feel of a Wood Warbler at times and did not have the agility and stance I often associate with Greenish Warbler. Furthermore, on a prolonged view from above, the upperparts were a very distinct green and not the greyish-olive of usual autumn viridanus. There was a distinct yellowish wash to the supercilium, which flared up prominently behind the eye and petered out in front of the eye. The dark line below the stripe also failed to stretch to the lores with the eye-stripes not encroaching or meeting on the forehead. The bird was very dingy on the underparts and not the silky-white one expects of Greenish and had a faint yellow wash to the ear-coverts, sides of throat and neck and on the leading edge of the flanks. The yellow did not however appear to be on the chin and throat, perhaps a significant feature. The distinct green colouring of the mantle and back was also apparent on the upperwings, with both sides of the bird bearing a broad, yellowish-tinged greater-covert bar, whilst one wing had a peppering of pale tippings to the median coverts. Comparing the bird's appearance with that of Dan Zetterstrom's artwork and a selection of Bright-Green Warbler photographs I had bought to the site, I was convinced that the bird was nitidus but at the same time, realised that the only call note the bird was repeating was that of a fairly typical viridanus - and at all times, the tri-syllabic contact note was not being uttered. Keith Vinicombe, Jim Lawrence, David & John Cooper, Bob Arnfield and many others agreed and after several hours of study (the bird was showing almost non-stop during the morning), departed the site around midday.

In the meantime, Ilya Maclean had very sensibly uploaded his MP3 recording of the Church Cove bird on the internet and had solicited response. Sound engineer and bird vocabulary expert Magnus Robb was quick to respond, declaring the calls typical GREENISH WARBLER. I must admit that I had fully expected such a response but still remained totally perplexed by the bird's appearance. I later contacted Magnus with some queries and he very kindly responded with the following -:

''Hi Lee, I'm in the luxurious position of not knowing much about the finer plumage points of Greenish and Bright Green Warblers, so for me the call identifies the bird 100% safely and securely! What I can tell you, is that all populations of viridanus known to me, at least as far as southeastern Kazakhstan, call like this. I don't know whether there is a cline in plumage towards the east as I do not have any recordings of Greenish Warblers from the Himalayas, China etc, cheers, Magnus''

I am not in the position to be able to argue with Magnus and fully accept his synopsis and expertise in this field. What I cannot tell is whether this Greenish Warbler, being such a late autumn migrant, is not from a population much further east than normal. What this whole chapter has proved once again is just how limited our knowledge is and how much more there is still to learn - this individual bird is an extremely educational bird and, just like the Staines Moor first-winter Brown Shrike, filling yet another major flaw and gap in our knowledge. Chris Heard had already commented to me that he was worried about certain aspects of Martin Elliott's field sketch and notes and it seems his concerns were well justified.

To make sure that this record is kept at the forefront of our knowledge, I would urge all of you today to email me your excellent images so that I can place for posterity a complete record of this bird and it can be used as a reference for future claims.

I would very much like to thank the large number of you that have got involved in the detailed discussion of this bird and have provided the wealth of material and information that has allowed it possible to come to a conclusion, especially the finders, the Cornish birders and of course Magnus and Ilya.