22nd July

With the heat continuing to build serious fieldwork was limited to the first few hours of the morning when there were plenty more signs of autumn passage gathering ground. The migrant tally at the Bill included 25 Sand Martins, a few more Swifts and Swallows, 2 Yellow Wagtails, a Hobby and a Dunlin through overhead and 5 Wheatears, 5 Willow Warblers, 2 Grasshopper Warblers and singles of Little Ringed Plover, Sedge Warbler and Spotted Flycatcher on the ground. Elsewhere a Black Redstart was a surprise arrival at Blacknor and 2 Sanderling, 2 Redshanks, a Whimbrel and a Black-tailed Godwit were at Ferrybridge; the Hooded Crow was also still at the Grove. Up to 100 Manx Shearwaters were lingering off the Bill where 30 Common Scoter and 2 Balearic Shearwaters passed by.

Two Clouded Yellows at the Bill were the first for some while. The moth-traps came up with signs of renewed immigration, including of particular note a Vestal and a Black Arches at Sweethill and 2 Splendid Brocades, a Saltmarsh Grass-veneer, a Sand Dart and a Tree-lichen Beauty at the Obs; more routine fare at the latter included 8 Dark Sword Grass, 5 Rusty-dot Pearl and singles of Small China-mark, Buff Footman, Four-spotted Footman and Silver Y.

Clay Crest Eucosma pupillana - Ferrybridge, 21st July 2014 © Martin Cade
...a decent moth anywhere in Britain, Portland has long been the only Dorset locality for this species. As recently as 20 years ago we used to see it tolerably often in the Obs moth-traps as well as encounter it relatively frequently amongst patches of the foodplant, Wormwood, around the centre and north of the island; however, in recent years development and the relentless 'tidying' of what many people regard as wasteground has led to a marked decline in Wormwood and increasingly infrequent records of the moth. Dave Gibbs kindly alerted us to his discovery of both at the weekend at Ferrybridge and the specimen featured above was readily chivvied from the plant there yesterday evening.
As an interesting contrast with the decline of pupillana, we were amazed at how abundant Long-winged Coneheads were in the tall grass beside the Beach Road at Ferrybridge:
...we're not quite sure when this species - which has undergone a remarkable recent range expansion in southern England and is now found throughout the island from Ferrybridge to the Bill - first arrived at Portland but it's something like 20 years ago; last evening many sweeps of the net through the grass came up with double-figure totals of this bush-cricket which must now have a population numbering in the many thousands in that area.