Moth Night at Yarner Wood

Devon Moth Group help celebrate Yarner Wood’s species richness on 20th May 2022

Nineteen people gathered for the first Devon Moth Group field meeting of the year and to celebrate national Moth Night. The theme of this year’s Moth Night was woodland, so Yarner Wood, part of the East Dartmoor National Nature Reserve, was a fitting location and we’re grateful to the warden Albert Knott for facilitating the event. Thirteen traps of various designs were deployed along rides radiating from the Woodland Centre. The night was cool and clear, though fortunately the wind had died down at dusk, so moths were relatively thin on the ground. Thankfully, the combined ‘firepower’ of our traps generated sufficient moths for beginners and experienced moth-ers alike to have an enjoyable evening.

Highlights included woodland specialists such as Plagodis pulveraria Barred Umber, Parectropis similaria Brindled White-spot and Drymonia dodonaea Marbled Brown, with the Bilberry understorey providing a few very fresh Hypena crassalis Beautiful Snout.

A total of 66 species was recorded, with many species associated with broad-leaf trees, such as Peridea anceps Great Prominent, Falcaria lacertinaria Scalloped Hook-tip, Lomographa bimaculata White-pinion Spotted and Jodis lactearia Little Emerald. It was also good to see several Lampropteryx otregiata Devon Carpet, which must breed along the stream. There were even a couple of migrants, in the form of Peridroma saucia Pearly Underwing and Agrotis ipsilon Dark Sword-grass. Sadly, micros were in short supply, perhaps because of the low temperature. Many thanks to everyone who came along and especially those who brought traps. It was lovely to be back in the field with a bunch of enthusiastic and friendly moth-ers after all the restrictions and disruption of the pandemic.

by Richard Fox

Although this was slightly disappointing night, given the effort, a true refection of the moth diversity can be found in the records Richard Fox made over 2021 – see his blog below …

Moths of Yarner Wood

Yarner Wood, now part of East Dartmoor National Nature Reserve, has been intensively surveyed for moths over many decades, not least thanks to it being a long-standing location in the Rothamsted Insect Survey (RIS) light-trap network This network is the longest running, national-scale monitoring of insect populations anywhere in the world and has contributed data to numerous scientific studies. From the RIS counts at Yarner Wood and many other sites, 50-year abundance trends have been calculated for hundreds of moth species in Britain1. The ongoing monitoring of moth numbers through the Rothamsted trap at Yarner Wood is very important but is not the focus of this article. Instead, this is a personal account of my moth recording in Yarner Wood during 2021.

After the travel restrictions and site closures associated with the covid pandemic in 2020, I was itching to expand my moth recording horizons last year. Most of my moth recording in recent years has been done at grassland and moorland sites, as well as in my garden near Newton Abbot, so I was keen to try trapping in woodland habitat for a change.

Woodland is a very important habitat for Britain’s moths. Our native species of birches support at least 121 moth species, oaks another 119, sallows a further 108 and hawthorns an additional 74 species2. Scores of other moths have caterpillars that feed on a range of different tree species. And that’s not to mention many species that are associated with plants of the woodland floor.

With that in mind, I was hopeful not only of busy evenings around the lights but also that I might encounter some species that I’ve never seen before. And I wasn’t disappointed; in 11 visits spread across the year from 9th April to 14th December, I recorded a total of 238 moth species at Yarner in 2021.

Visits typically involved arriving shortly before dusk on a mild evening and setting up three or four moth traps. My traps vary in design, but all use a light source, powered either by a portable generator or by battery, to attract nocturnal moths, which can then be identified and noted down. Sometimes I had the pleasure of sharing exciting finds with the warden Albert Knott and his family. At the end of the evening, decided either by sheer tiredness or a deterioration in weather conditions, all of the moths are released to carry on their lives and the traps packed away.

While my visits followed this standard basic pattern, each was unique. For one thing, I tried to sample a range of different locations through the reserve, as different species are found in different habitats. In addition, each moth species has its own specific flight period during the year, so even in exactly the same spot, different moths will be encountered in the spring, summer, autumn and winter. Finally, as with most wildlife watching, there is a big element of chance, which greatly adds to the excitement – you never quite know what you are going to see.

My best night at Yarner was also my best night of the whole year, when I recorded 109 species near the old pump house at the top of Yarner Wood on 16th July. Edges between habitats are often productive places to run moth-traps, and this was no exception, with my lights attracting moths that inhabit the neighbouring moorland and grassy areas, such as Small Purple-barred, Striped Wainscot and Grass Emerald, as well as woodland residents.

Even some of the expectedly quieter evenings brought excitement and enjoyment. My first visit of the year, on 9th April, on a chilly evening, yielded my first ever Marbled Pug, a nationally scarce species associated with mature oaks. Some highlights like the Marbled Pug were completely unexpected to me, others I specifically targeted, visiting at the right time of year and placing my traps in what I hoped were likely locations. Another pug species, Bilberry Pug, was a good example of the latter. Again, it is an uncommon species in Britain, mainly concentrated in the west, and again it is quite a looker among a group of moths (the pugs) which are notorious for being small, brown and difficult to identify. As its name suggests, this species is completely dependent on Bilberry, the only plant that its caterpillars eat. Bilberry is common on the woodland floor at Yarner and, as well as numerous Bilberry Pugs, I enjoyed seeing other moths that specialise on this plant including Northern Spinach and the aptly-named Beautiful Snout.

In all I saw 13 species that I’d never recorded before in my 20 years of moth recording and lots more that I’d only encountered on one or two previous occasions. Many were woodland stalwarts, including my hands-down best find at the site – a tiny but brightly coloured scrap of life called Schiffermuelleria grandis. It is a nationally rare species with caterpillars that live in dead wood. The one I recorded on 10th June near the site of the old field museum, was my first ever, only the 6th in Devon this century and only the 11th ever in the Devon Moth Group database.

It was a delight to spend time among the trees and calling owls at Yarner Wood during the year and I’m very grateful to Albert and Natural England for encouragement and permission to survey moths at the site. All my records have been passed back to Albert to add to the knowledge of the site, as well as being submitted to Devon Moth Group, the Devon Biodiversity Records Centre and the National Moth Recording Scheme. It was a successful year for me, but there are undoubtedly numerous other moth species living at Yarner that I did not encounter on my visits. Certainly plenty for others to record in future years!

Written by Richard Fox


  1. Fox, R., Dennis, E.B., Harrower, C.A., Blumgart, D., Bell, J.R., Cook, P., Davis, A.M., Evans-Hill, L.J., Haynes, F., Hill, D., Isaac, N.J.B., Parsons, M.S., Pocock, M.J.O., Prescott, T., Randle, Z., Shortall, C.R., Tordoff, G.M., Tuson, D. and Bourn, N.A.D. (2021) The State of Britain’s Larger Moths 2021. Butterfly Conservation, Rothamsted Research and UK Centre for Ecology & Hydrology, Wareham, Dorset.
  2. Young, M. (1997) The Natural History of Moths. T & AD Poyser Ltd, London.

Richard Fox is a local moth and butterfly enthusiast and recorder. When not out recording, he works as the Head of Science for the UK charity Butterfly Conservation and is also Chair of Devon Moth Group.

More information about Moth Night can be found here

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