I am wary to post this in relation to a sighting, knowing that birders well superior to me, including BBRC, have examined this. Its certainly a thread for a long, cold winter's day.
This is in relation to the sighting of an 'acrocephalus' species that was found by Kenny Dummigan at Red Rocks, Cheshire between October 6th - 10th 2007, and submitted by him self and Mark Garner, Jane Turner, as well as Cheshire & Wirral County Recorder Hugh Pitsford, as Blyth's Reed Warbler. A fine supporting cast !
It was not entirely surprising that without 'call' recordings, and due to a few untypical features (long bill, plain face, lack of clear supercilium), it was found 'unproven' by BBRC- though the County Recorder Hugh Pitsford did conclude thereafter that he was happy that it was a BRW & that had recordings been submitted it was likely to have been accepted.
I have been trying to obtain images of this bird (as have several I gather). The only ones submitted to BBRC were by Professor Peter Wheeler, and although I have contacted him by email offering to pay for copies I have heard nothing - of course that is his absolute perogative without inference. Why should he respond to a mere mortal like me?
Why the fixation? - subsequently Large-Billed Reed Warbler articles have been published highlighting the discovery of populations of this species (alongside BRW) at Wakham Corridor in Afghanistan in 2009, & in Tajikistan, & highlighting the huge similarity between species in appearance & call. Furthermore a specimen in the Natural History Museum at Tring labelled as "acrocephalus dumetorum" (Blyth's RW) was re-identified as LBRW. Indeed, Lars Svensson, in his paper, concluded 'that there is an extreme similarity between LBRW & BRW', & 'the former (LBRW) has probably been overlooked and mistaken for the latter species in the field'.
I have contacted a member of BBRC, who I must stress was out of the country & hence unable to check any records, but who kindly responded that he did not recall consideration of LBRW with this sighting. He has stated that he would check upon his return.
There is an excellent thread on Birdforum in relation to this sighting, but key notes highlighted regards the Red Rocks bird were as follows :-
* plain unmarked face except pale area before the eye (more characteristic of LBRW)
* long, spikey bill, darkish upper mandible, all pale lower mandible without spot (more characteristic of LBRW).
* white incomplete eye rings (ok for both)
* white throat and buff flanks & UTC's (perhaps more typical for LBRW)
* uniformly olive upperparts (ok for both)
* greyish legs (ok for both)
* tacking call (ok for both)
* typically short primary projection (ok for both but further scrutinisation required - photos insufficient I believe)
* seen in 'banana' posture several times (better for BRW?)
* constantly 'cocking' & 'fanning' tail as it moved (considerably better for LBRW) (Svensson notes "fanning of the tail is maybe a useful characteristic, though birds seen doing this are not 100% LBRW")
Of course the balance of probability regards vagrancy here has to be considered, LBRW should be migrating to winter via the Himalayas to Northern India & SE Asia. BRW is more likely.
But have we missed a trick? At the time of submission, I doubt anyone (including BBRC) even considered the alternative. BRW are themselves extremely difficult birds to identify, given the difficulty of obtaining prolonged. clear views. So, it is not that I consider my self as being the appropriate or capable enough birder to suggest a re-examination of this record, it is more that I wonder if this alternative was considered at the time. It was 'mooted' afterwards by a few others.
Can, and would BBRC re-examine records in light of such 'indirectly' relevant information?