Chalk grassland species

The Grangelands SSSI at Cadsden near Princes Risborough is one of my regular trapping locations this year and for the May visit I decided to join last night's Bucks Invertebrate Group field meeting on the site.  It might not have been the best night to choose because chalk grassland species haven't really come into their own yet.  Coupled with the recent poor weather (plus a heavy downpour there yesterday afternoon!) meant that there was little of excitement in the catch even though the full moon was hidden behind cloud cover for much of the three-hour session.  It was completely still at dusk but a light down-slope breeze eventually set in, resulting in a quick drop in temperature and a build up of mist at the bottom.  Thankfully my one target species for this visit, Light Feathered Rustic, put in an appearance at about 11.30pm and by the time we'd packed up an hour later three more had entered the traps.  This is a UK Scarce species restricted to chalk down-land habitat and its surviving strongholds in Bucks are the Grangelands area and the Ivinghoe hills.

Light Feathered Rustic, Grangelands 18th May

The only surprise (to me, anyway, and it shouldn't have been!) was the appearance of a fresh green Little Emerald at one of the traps.  On checking I found that it is actually known previously from the site and other locations in the Chilterns as well as its more obvious stronghold in Bernwood Forest.  Seeing a green one is a rare event because they fade to white very quickly.  Light Brocade and Treble Lines were the most abundant moths of the evening and Shears and Nut-tree Tussock also visited most of the traps, but there was little else of note.  The unusual form of Treble Lines shown below was worthy of a photograph though.

Treble Lines, Grangelands 18th May

Dave Wilton
Westcott, Bucks