Grangelands, Bucks

A three-hour session with a couple of Robinson MV traps and a 15w synergetic Heath trap at BBOWT's Grangelands nature reserve near Princes Risborough last night brought in 35 species in three hours, not a brilliant total but exposed chalk grassland always seems to lag behind woodland as a habitat at this time of year.  Treble Lines (56) was the most abundant moth, followed by Light Brocade (37), while Small Elephant Hawk-moth and Shears, both of which should also soon be around in some numbers at the site, were just starting out.  The best sighting was Light Feathered Rustic, two individuals proving that the small colony here is still hanging on, but even better was to get only two Cockchafers!  The only other moth species in the traps which I hadn't yet seen anywhere this year were Argyresthia trifasciata, Ancylis unculana, Anania fuscalis, Common Carpet, Treble-bar, Peppered Moth, Willow Beauty, Lobster Moth, Nutmeg & Lychnis.  

Ancylis unculana, Grangelands 22nd May

Small Elephant Hawk-moth, Grangelands 22nd May

Light Feathered Rustic, Grangelands 22nd May

Nutmeg, Grangelands 22nd May

However, the main reason for going to Grangelands was to look yet again at the Junipers there for some of the tiny and rare Argyresthia micros which feed on them.  Over the past couple of years I've found Argyresthia arceuthina, Argyresthia abdominalis and Argyresthia dilectella but there are two others, Argyresthia praecocella (flies in April/May) and Argyresthia aurulentella (flies in July) which might be present but haven't yet been recorded at the site.  James Hammond and Will Langdon have had success finding praecocella in recent weeks at sites in Oxon which have Juniper by using techniques other than light-trapping (as I've already found out, these species seem to be quite sedentary and none of them is keen on coming to a light trap).  Based on their advice, after dark last night I tried tapping branches of Junipers bearing fruit - praecocella larvae feed within the berries - and then trying to net whatever might fly out.  My netting skills aren't up to much and after a few failures it soon became clear that these tiny moths would launch themselves in completely the opposite direction to the glare of my head-torch and often deep into the dark vegetation.  However, perseverance resulted in eight Argyresthia specimens being potted up within an hour.  Five were clearly freshly-emerged examples of Argyresthia arceuthina, but the other three were different, being quite worn but seemingly lacking a white thorax, so may yet prove to be the hoped-for Argyresthia praecocella.  Time, along with Peter Hall's skill with the scalpel, will hopefully tell...

Argyresthia arceuthina, Grangelands 22nd May

Dave Wilton Westcott, Bucks