Bonelli’s Warbler v Western Bonelli’s Warbler

Phylloscopus bonelli/ Phylloscopus orientalis

There have been three records of ‘Bonelli’s Warblers’ in Pembrokeshire. The first ever record for Britain was an individual on Skokholm on 31st August, 1948 (PJ Conder, J Keighly). Pembrokeshire’s second was also on Skokholm, 31st August, 1991 (M Betts).

In 1997 Bonelli’s Warbler was split into two species and is now called Western Bonelli’s Warbler (Phylloscopus bonelli) occurring in South-west Europe and Italy and Eastern Bonelli’s Warbler (Phylloscopus orientalis) originating in South-eastern Europe and West Turkey.  There are subtle plumage and biometric differences between the two as well as clearly differing calls. A review by BBRC of the first two Pembrokeshire records identified the 1948 birds as ‘Western’ but the 1991 bird was not able to be specifically identified.

The third record, a Western Bonelli’s Warbler  was present on St Davids Head on 3rd October, 2011 (M Young-Powell et al). The plumage differences are slight to non-existent and there was no opportunity for biometrics to be taken so specific identification rested on the call. The bird frequently called as per Willow Warbler, an uprising ‘hooeet’ with something of the sharp tone of a finch in it). This was sufficient to identify the bird as Western Bonelli’s the  only Pembrokeshire record thus far.

MYP 29/05/2013

More about the Bonelli’s Warbler in Pembrokeshire