19th August


A reminder that there's an InFocus field day at the Obs between 10am and 4pm tomorrow, Saturday 20th August.

When an Icterine Warbler and a succession of Pied Flycatchers emerged from the first looks at the Obs mist-nets in the dreichy gloom of post-dawn there were high hopes that a really good drop of migrants was unfolding; sadly, this optimism was soon crushed as the sun emerged, warmth built and, if indeed anything else had arrived, it evaporated in an instant.

Portland Bill
Grounded migrants Wheatear 30, Willow Warbler 15, Pied Flycatcher 8, Yellow Wagtail 7, Spotted Flycatcher 2, singles of Tree Pipit, Whinchat, Reed Warbler, Sedge Warbler, Icterine Warbler and Firecrest.
Visible passage Swallow 30s, Sand Martin 5s, Grey Heron 1n.
Sea passage Balearic Shearwater 17w, Sandwich Tern 7w, Common Gull 2w, Arctic Skua 1w.

Pied Flycatcher 2.

Ringed Plover 205, Dunlin c150, Sanderling 3, Knot 2, Common Gull 2, Redshank 1.

Selected immigrants Obs: Rusty-dot Pearl 31, Rush Veneer 15, Diamond-back 4, Dark Sword Grass 2, singles of European Corn-borer, Pearly Underwing, Small Marbled and Beautiful Marbled.

Birds have a lovely way of confounding what you've just written about them and making you seem even more stupid than you already are. By the time we got to see this morning's Icterine Warbler nestled in another ringer's hand there was some ongoing debate about its identity: the primary projection wasn't immediately apparent, it had no obvious wing panel and a request to count the emarginations elicited the response that it had three - a Melodious it must be. Of course it only took a quick measurement of the wing (79mm as opposed to yesterday's 67mm-winged Melodious) and a closer look at the bird to see that it was perfectly obviously an Icterine...

The anomalous features are certainly worth a mention though. An emargination on the 5th primary was very clearly present even if it wasn't quite as well formed as the emarginations on the 3rd and 4th primaries - Icterine can have this although it isn't usually present. Also check out the length of the 1st primary: this ought to fall a little way either side of the end of the primary coverts on an Icterine but clearly fell way beyond them on today's bird and so was of length much more likely for a Melodious. As for a wing panel one was hardly visible at all in the hand although we could just about imagine that, in the field, a coming together of the secondary edges might just make it a little more obvious.

On the plus side, and from a field ID perspective, the primary projection was huge, the bird was just that little bit more cold-toned than yesterday's Melodious, the throat was a little more lemon-tinted, the underparts were silkier white and, from certain angles at least, the tertials were really dark-centred © Martin Cade: