11th May

It's been too many days coming but May sprung back to life on the migrant front today, with a small flurry of new arrivals and a nice rarity in the form of a Western Bonelli's Warbler that popped up in the Obs garden during the afternoon. Damp, dreary conditions through the morning were enough to ground a fair sprinkle of birds, amongst which Sedge Warbler, Garden Warbler, Blackcap, Chiffchaff and Willow Warbler all reached 10-20 totals at the Bill; a fair bit of other variety included 2 White Wagtails and singles of Hobby, Short-eared Owl, Black Redstart and Wood Warbler there and 100 Dunlin, 18 Sanderling, 4 Whimbrel, a Grey Plover and a Bar-tailed Godwit at Ferrybridge. Poor visibility again hampered seawatching, with no more than 3 Little Terns and a Great Northern Diver through off the Bill and 2 Great Northern Divers and a Black-throated Diver still in Portland Harbour.

Western Bonelli's Warbler - Portland Bill, 11th May 2015 © Martin Cade

We thought this was a pretty tricky bird that, at least until it called, wasn't at all obvious as a Western as opposed to an Eastern Bonelli's. Plumage-wise, maybe our problem was having been spoilt by handling nice, bright, fresh young Western Bonelli's in both the last two autumns; in comparison, today's bird looked positively dowdy which better fitted with our now fading memory of the 2009 Southwell Eastern Bonelli's. The top two tertials and the greater coverts also looked to be rather bleached and greyish which we've seen mooted as a feature favouring Eastern. The wing detail also marginally favoured Eastern; there was nothing even approaching a clear-cut emargination on the 6th primary (much better for Eastern):

...whilst the 2nd primary fell more or less equal with the 6th (an either/or answer; but since our last two Westerns both had 2nds that fell conspicuously shorter, at the back of our mind we likely construed this - erroneously - as favouring Eastern as well!):

Fortunately, on release the bird flew straight to the nearest tree and called very clearly - the gathered audience featuring in our little recording handily let us know in no uncertain terms what the answer to today's conundrum is:

Finally, we weren't able to secure any video of the bird in the field until late in the day when the light had faded and the garden was shrouded in fog: