Friday, 24 July 2020

Chilterns Chalk Grassland

Having read Will Langdon's post from the other day about Aston Rowant I thought it was about time I attempted another visit to the Grangelands nature reserve near Cadsden, Bucks.  Last night probably wasn't the best of choices in that there was an annoying breeze for most of the session, but it didn't rain and there was cloud cover for much of the time I was there.  Two MV traps were run for the usual three hours and somewhere in the region of 150 species eventually turned up after quite a slow start.  One trap was placed in amongst the largest Juniper bushes on site and some of the expected Juniper feeders did make an appearance, including probably two of the five different Argyresthia moths associated with the plant (abdominalis and dilectella, both miniscule and very similar species) as well as Dichomeris marginella and Juniper Pug.

Argyresthia sp. Grangelands 23rd July

Juniper Pug, Grangelands 23rd July

The Argyresthia species will need dissection to confirm but either of the two likely species will be new to the site.  A.dilectella is known in Bucks from three rather dubious-looking records back in the 1960s and 1970s from someone who only seems to have recorded moths associated with Juniper and there's no indication of how their identities were established.  However, there are post-millennium records for A.abdominalis from Windsor Hill and Burnham Beeches.  It is perhaps worth mentioning that the second trap was placed only about 40 metres away from this one and it didn't get any Juniper feeders at all, so maybe proximity to the food-plant is quite important.

Amongst the other micros it was good to see Acompsia cinerella, Acompsia schmidtiellus, Ancylis comptana, Rhopobota stagnana, Paratalanta hyalinalis, Oncocera semirubella & Delplanqueia inscriptella along with many more.

Ancylis comptana, Grangelands 23rd Jul

There were no large numbers of particular macro species but Shaded Broad-bar, Scarce/Common Footman, Brown-line Bright-eye, Straw Underwing & the Hoplodrina pair were reasonably frequent.  Other noteworthy species included Royal Mantle (just the one), Barred Rivulet, Kent Black Arches, Rosy Minor, Tree-lichen Beauty & Small Purple-barred (several, including a rather more fresh example than Steve Lockey's specimen from the other day, although they do fade very quickly).  No sign, unfortunately, of Chalk Carpet which is the species I'd most hoped to see at this, one of its few known Chilterns sites (I didn't get it here last year either which is a bit worrying). 

Royal Mantle, Grangelands 23rd July

Small Purple-barred, Grangelands 23rd July

Dave Wilton
Westcott, Bucks

3 comments:

  1. An interesting account of what sounded like a pretty successful session.

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  2. Great stuff, Dave! Well done on those Argyresthias, and interesting to hear where you sited the traps. Only one of mine was 10-15m away from a big Juniper, so will have to try a little closer next time. I've tried tapping the bushes by day as well, but no luck so far. I was told by David Aggasiz that all the juniper-feeding Argyresthias have been recorded in the past at Aston Rowant, so I will persist.

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  3. Dave, the person who you say "only appeared to record moths associated with juniper" was Lena K Ward who did a lot of work on Juniper and animals associated with it (not just moths). I think some of this work was carried for what was probably the Nature Conservancy at the time (may have been a slightly newer title). She has been involved with many publications on juniper (including book(s)) and other aspect of chalk grassland and other habitats concerning conservation and ecology.

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