Moths and butterflies

Pearl-bordered fritillaries are one of the earliest of the three Focus Species to emerge in the spring flying from late April into May. They’re very sedentary and some will only travel a few metres to new habitats although others will fly up to 400m. Studies have shown that even a 10 year coppice growth can be a complete barrier to low flying females. Caterpillars prefer to feed on common dog-violet but will feed on marsh dog- violet and heath dog-violet.

In Devon, they’re mainly found on the moorland fringes and woodland edges of eastern Dartmoor, although smaller colonies survive at Torrington Common, Marsland DWT Reserve, and Lydford Butterfly Conservaton Reserve. They’ve disappeared from former sites like Roborough Common and Ashclyst Forest, reflecting a significant national decline—around 90% since the 1970s.

The small pearl-bordered fritillary is a fast-flying butterfly which can be seen during May and June. They are widespread across Devon but in significant decline. They typically travel 1–2 km, although will go as far as 5 km, so are vulnerable to habitat fragmentation. Caterpillars prefer common dog-violet and marsh violet. 

In Devon, they’re found in the Rhos pastures of Dartmoor, north Devon culm, wet heaths in the Pebblebeds and wetland mosaics in Haldon and the Blackdown Hills.

The high brown fritillary is a large, fast-flying butterfly with striking orange and black wings that can be seen soaring above bracken and low vegetation in woodland clearings.  It is the latest flying of these three fritillaries and can be seen in June and July.  Caterpillars feed on common dog-violet.   

The high brown is a strong mobile butterfly which is known to fly 1-2km to reach good habitat.  With good weather conditions it could possibly colonise new habitat 10-15km away. 

The British population has undergone a massive decline and this is Britain’s most endangered butterfly.  It is now only found at Morecombe Bay, Dartmoor, Exmoor and one site in Wales.  It’s range in Devon has contracted and it’s now confined to two areas on Dartmoor (eight sites in the Dart Valley and four in the Walkham Valley) and Exmoor (nine sites in the Heddon Valley.  There have been occasional sightings at Haytor and Trendlebere on Dartmoor.    

The marsh fritillary is one of the UK’s most threatened butterflies, having suffered severe declines due to habitat loss and fragmentation. In Devon it’s found in wet acid grasslands where the caterpillars’ foodplant, devil’s-bit scabious, grows.

Adults lay eggs in clusters of up to 200 on a single leaf. The caterpillars weave distinctive silk webs which act as communal nests. Marsh fritillaries are thought to need habitat patches no more than 500m apart, but are known to use small patches of habitat as stepping stones to move between larger breeding sites. Isolated populations rarely survive.

Dartmoor is Devon’s stronghold, with core populations found across four metapopulation networks: Tor Valley, Fernworthy-Long Lane, Postbridge-West Webburn and Walkham Valley. In north Devon there are three metapopulation networks, centred around Volehouse Moor in the north-west, Knowstone and Rackenford Moor and Witheridge Moor in the north-east, with a smaller population close to Cookworthy Forest, centred around Luckcroft and Common Moor. Blackdowns?

The caterpillars of this moth also feed on devil’s-bit scabious and in Devon the two species are largely found in the same habitats. However, the hawk-moth isn’t currently found in the Blackdown Hills and is restricted to Rhôs pastures on Dartmoor and culm grasslands in north-west Devon. Once widely recorded over much of Britain, it has disappeared from most of its historical range.

The caterpillars of this nationally rare moth feed on eared willow, which grows in open sunny areas such as north Devon’s culm grasslands. It’s rarely found in areas with spring and summer grazing. In Devon, the most recent records are from culm grassland at Hollow Moor, near Holsworthy.

See the bracken and violet butterflies group for more information.

This species was discovered in 2004 in Hembury Woods. Since then it has also been recorded in the Dart Valley and at Chudleigh Knighton Heath. It hasn’t been found anywhere else in the UK.

The adult moths have never been photographed. However, the distinctive bright green caterpillars can be seen from August to early September when they eat oak leaves. They overwinter in a cocoon on the ground.

A very rare micro moth thrives in humid woodlands where the caterpillars feed on decaying wood found under the bark.  It is currently found in the Teign Valley.

Relies on dead wood and possibly fungi with records from Hembury Woods and southern Dartmoor.  This is a rare micromoth restricted to a few ancient woodlands in the midlands, south Wales and southern England. 

Endangered and declining, feeds on oak and is found in Hembury Woods and other sites.

This micro-moth can be seen flying in the evening from late July to early August.It’s been found at Petit Tor Point and Berry Head but otherwise is only known to be at Portland.

This moth was commonly found in a small area of the Torquay coast, where the caterpillars fed on dead leaves of the small-leaved cotoneaster. However, between 2008-2011 the plant was sprayed with herbicide and the moth was last recorded in July 2011. It has not been seen since and could be extinct.

Moths fly from late June to August. Caterpillars build a case out of silk. In Devon, they only feed on goldilocks aster so depend on this sole foodplant.  Goldilocks case bearer was found in Berry Head in 2013. Apart from  his one site in Devon, in the UK it is only found in the Thames estuary in Kent and Essex, where it feeds on sea aster.

A scarce species which is declining in range and is now only found on heathland in the south of England.  The main  caterpillar foodplants are heather and birch.  Moths fly in June and July. The small grass emerald has been recorded on the Pebblebed heaths, eastern fringes of Dartmoor and at Beaford Moor.  

The brown hairstreak is considered one of the most elusive butterflies in the UK. Adults are rarely seen as they spend most of their time high in trees. They come down to lay eggs on young blackthorn leaves, often on warm south– facing hedges or scrub (so usually below 250m). Their UK population has declined significantly due to the loss of hedgerows and annual flailing. 

Devon is considered a stronghold and while they’re thought to be across the county more survey is needed. However, populations are known to be in the Blackdowns, Torbay and mid-Devon. The most effective monitoring method is counting eggs from late October to early March, when they can be seen on young twigs.  

These moths both have caterpillars which feed largely on hawthorn and blackthorn as well as some other broadleaved trees and shrubs.  Both species were once widespread across Devon’s farmed landscape.  They are now more often found in coastal areas and nature reserves.  The lappet is largely confined to the Exe catchment.