Tuesday, 21 July 2015

Homefield Wood again

I made another visit to Homefield Wood near Marlow, Bucks last night, where the trees provided a good screen from the stiff SW breeze.  There was plenty of moth activity although very little from species that I haven't already recorded there this year.  Clouded Magpie was out in force with 23 recorded between the three lights.  Black Arches was also numerous and one of them I brought home to photograph because it looked rather dark and it turns out to be a melanic form which is illustrated in Skinner.

Melanic Black Arches, Homefield Wood 20th July 

It was also nice to see August Thorn and September Thorn side-by-side because I've struggled with this pair in the past and I'm sure others do too!  When at rest the August Thorn (upper) holds its wings at a lower angle and the two cross lines remain fairly widely spaced when they reach the lower edge of the forewing.  September Thorn (lower), which is a 'chunkier' moth, holds its wings higher and the cross-lines come much closer together at the lower edge of the forewing. 

Amongst the micros at Homefield Wood, Pseudopostega crepusculella appeared again and Monochroa cytisella was out in numbers (16 seen).  My best find, though, was what I hope is the crambid Pediasia contaminella which, if correct, appears to be only about the fourth record for Bucks.
Possible Pediasia contaminella, Homefield Wood 20th July
While at the wood I completed a torchlight survey of the dark mullein growing there.  More than 200 plants were checked altogether and eight Striped Lychnis caterpillars were found, one in BBOWT's meadow area and the rest along the main Forestry Commission ride.
Dave Wilton


  1. Nice comparison shot of the two Thorns, Dave - would also like to see a Clouded Magpie - is there anywhere near to Aylesbury that you've seen them?

  2. 23 Clouded Magpies! The Black Arches is quite a variable moth normally. My question is, did you notice much variation between the Clouded Magpies? They are closely related to Magpies, which certainly vary a lot.
    The Pediasia is quite a rare moth, was that in woodland or on meadow-land?

  3. One of the reasons for getting FC permission to trap regularly in Homefield this year was the amount of wych elm in certain areas of the wood. It has previous records for typical elm feeders such as Blomer's Rivulet, Clouded Magpie and Lesser-spotted Pinion which are quite difficult to find in Bucks these days. Clouded Magpie is obviously still doing quite well there, even if Blomer's isn't! I didn't look too closely at every one but didn't notice any significant variation at all.

    The fact that the Pediasia was caught on a ride cross-roads deep in the heart of the wood was what made me think that it needed to be checked because the books suggest that its habitat is typically open areas of dry grassland such as golf courses. However, two of the three other Bucks records (confirmed by dissection) are from the RIS trap at Burnham Beeches which is also sited in woodland. It either wanders occasionally or else people have been looking for it in the wrong places!

    1. Do people go looking for it?! It surely suffers from being a non-descript grass moth and maybe it's under-recorded. I've encountered it once, at Croxley Common Moor in Herts. This is open country, a bit scrubby in places and half dry-ish and half marshy. Typically, I suspect, it was a make-weight I took in 2012 and only bothered to dissect this year, in the winter!


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