The West Country

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An area on the edge of the species' range

The White-letter Hairstreak is still recorded in Devon and Somerset but there have been no records from Cornwall since the 1980s. However, even in Devon, the species appears to be very localised and there are many areas where the species has not been recorded for some years. In the summer and winter of 2008 and spring 2009, Andrew Middleton and Liz Goodyear, visited the area to try and find out why.

Distribution map based on records in the Butterfly Conservation national data base, Devon Branch website (2008) and Andrew Middleton and Liz Goodyear personal records from 2008 and 2009. Updated January 2018 to show additional records reported since 2013.

Reproduced from 'Miniscale' Ordnance Survey maps by kind permission of Ordnance Survey on behalf of The Controller of Her Majesty's Stationery Office. (c) Crown copyright 2009 All rights reserved. Licence number AL 100015237

It is understood that Dutch Elm Disease [DED] ripped through Devon and Cornwall in the 1970s. We feel that unlike other areas of the country, where the species had potential to move around and disperse to healthy elm, the White-letter Hairstreak, found itself with no where to go. However, even before DED, reports were restricted to only a handful of sites despite the probablility that there was sufficient elm to support the butterfly.

The Cornish elm was known to suffer badly from the effects of DED and we have been told that no mature trees survived. However, we have also been told the White-letter Hairstreak does not breed on Cornish elm?

Throughout our visits to Devon and Cornwall we have looked at many of the historic areas and tried to find good examples of healthy elm throughout the county, which if we were in the south east of England would without doubt support a colony of White-letter Hairstreak. We have also sampled for eggs on many of these examples but did not find any white-letter eggs!

We have been very lucky and found eggs at Porlock on the Somerset / Devon border and in the Lynton Gorge. Neither of the areas had had reports of White-letter Hairstreak for about 20 years (Diane Andrews had a adult sighting at Porlock in 2007). However, attempts to find the butterfly at Torpoint where there is a large amount of elm proved negative despite an egg being found less than 2 miles away at Bere Ferrers on the other side of the Tamar. There is still elm at Veryan where the last Cornish records came from and in the Camel Valley although much of the elm near Bude has gone (historic area).

In future we suggest priority should be given to watching elm on Torpoint, Veryan, the Camel Valley and close to Falmouth. We would suggest that coastal areas or river valleys (preferably limestone) with large leaved elms have the greatest potential. This would also apply to the north Cornish/Devon coast.

The story since 2013 in Cornwall!

In January 2013, we were asked by Butterfly Conservation Cornwall Branch to conduct a through winter egg search (prior to a possible re-introduction attempt) and we focused our searching on areas west of the River Tamar, especially Torpoint, and the A38 corridor towards Bodmin over a period of six days.

On our way there we stopped just east of Plymouth and found an old hatched egg in SX55. On day three, we found eggs at two sites, one egg in SX35 (9km from the Devon/Cornwall border) and two eggs in SX45 on Torpoint by the edge of woodland (1km from the Devon/Cornwall border). These were both in areas where we had searched in previous years.

In July 2014, we were informed by Cornwall Branch that an adult White-letter Hairstreak had been recorded in a garden just north of Callington in SX37 (2.5km from the Devon/Cornwall border and River Tamar).

In August 2016 a member of Head Office Staff was walking a Wider Countryside Survey 1km square near the River Camel, when he reported a White-letter Hairstreak in SX07. This is a considerable distance from any other recent record, but in an historic area, and where we had heard rumours of possible sightings during the project. We had visited the Grogley Halt area beside the River Camel in 2009 but had not found much elm although we did not visit during our survey visit in 2013.

The Cornwall Branch newsletter of Autumn 2017 also reports a sighting near Saltash in 2017 on page 24. (Not mapped because exact location is not known but the sighting was probably fairly close to other records reported near the River Tamar)

Unlike Cumbria, the spread of White-letter Hairstreak in the Devon and Cornwall area seems very slow, and the butterfly appears to be quite rare with a restricted distribution concentrating on key river valleys.

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Liz Goodyear and Andrew Middleton
June 2009 (revised January 2018)