1. Introduction. 19 species of butterflies have been recorded in Assynt, out of the 30 that are known to occur in Highland, and some 70 in the British Isles as a whole. Our local butterfly fauna is therefore limited, as you would expect in the north-west of Scotland. However, we do have good populations of species such as the large heath, small pearl-bordered and dark green fritillaries that are scarce further south. Some ‘new’ species have also spread into Assynt in recent decades, such as speckled wood, peacock and orange-tip, and with climate change, others may well follow. So, recording butterflies locally is well worthwhile, and the purpose of the notes that follow is to give you some idea what to expect.
2. Butterflies found in Assynt. This list uses the order followed in the Atlas of Butterflies in Highland and Moray (Barbour, D. et al., 2008), which gives an up-to-date picture of distribution and status across the Highland area, with good illustrations and hints on identification.
Clouded Yellow Colias croceus: a migratory species for which there were three local sightings in 1992, the year of the last major influx.
Large White Pieris brassicae: the familiar ‘cabbage white’, a serious pest of brassicas in gardens. Thankfully, it occurs only sporadically in Assynt, and its numbers are probably re-inforced by migration.
Small White Pieris rapae: another pest of brassicas, but very rarely seen locally, with just one record, from NC13.
Green-veined White Pieris napi: perhaps the commonest butterfly in Assynt, especially in marshy places, where cuckoo-flower, a favourite food of its caterpillars, occurs. The spring brood of adults fly from April to June and the summer brood from July to September.
Orange-tip Anthocharis cardamines: a recent addition to our butterflies, and still scarce. The caterpillars also feed on cuckoo-flower.
Small Copper Lycaena phlaeas: there are only a couple of recent records of this unmistakeable butterfly both from coastal areas.
Common Blue Polyommatus icarus: an attractive butterfly, found where its larval food plant, bird’s-foot trefoil, occurs in quantity, especially along the coast and the limestone corridor.
Red Admiral Vanessa atalanta: a familiar garden butterfly, whose caterpillars feed on nettles. Formerly occurred only as an immigrant, but may well now survive mild winters in hibernation.
Painted Lady Vanessa cardui: a migratory species, that occurs most years, sometimes in considerable numbers. Usually arrives in June, with a locally-bred second generation, from caterpillars feeding on nettle and spear thistle, in the autumn.
Small Tortoiseshell Aglais urticae: our resident vanessid, hibernating, often in buildings, and appearing in April, with a second generation about August. Somewhat reduced in numbers recently?
Peacock Aglais io: once very rare in Assynt (and Highland as a whole), this butterfly had a remarkable extension of range in 2006 into Assynt and on to the north coast of Sutherland. It will be interesting to see if it maintains its presence here.
Small Pearl-bordered Fritillary Boloria selene: this lovely chequered orange butterfly flies in June and July in boggy areas, where its caterpillars feed on marsh violet. Widespread in Assynt.
Dark Green Fritillary Argynnis aglaja: a larger fritillary, with tawny wings (the dark green refers to the underside). Flies in July and August in grassy and moorland areas, where the larval foodplants, violets, occur. Widespread in Assynt.
Speckled Wood Pararge aegeria: almost unknown in Assynt until the 1990s, now widespread in gardens, scrub and woodland around the coast. Two broods of adults, May- June and July-October.
Scotch Argus Erebia aethiops: a dark chocolate-brown butterfly with distinctive wing-spots. Once very rare in Assynt, but increasing in numbers in grassland areas, where its larval food-plant, purple moor-grass occurs. Now locally abundant just to the north of Assynt and may have been overlooked here. Flies in August.
Grayling Hipparchia semele: a coastal butterfly that may have been under-recorded in Assynt. Flies in July and August and sunbathes on rocks and paths, with its wings tilted at right angles to the sun.
Meadow Brown Maniola jurtina: probably the second commonest butterfly in Assynt, flying in grassy places in July and August. Larger and lighter in shade than the Scotch Argus and with a single eye-spot on the fore-wings.
Small Heath Coenonympha pamphilus: a small butterfly of coastal and limestone grasslands in Assynt, with grey and orange undersides to the wings. Not widespread, but may be frequent where it occurs. Flies from June to August.
Large Heath Coenonympha tullia: a characteristic butterfly of boggy areas in the Assynt landscape, where the caterpillars feed on hare’s-tail cotton-grass. A strong flier, June-August, that requires careful identification where the Small Heath might also occur (see the Atlas).
3. Good places to see butterflies in Assynt. The best places are where there are a good variety of flowers, especially thistles, from which the adults can gather the nectar on which they feed, such as sheltered clearings, un-cut road verges and gardens. Some sections of the old road along Loch Assynt (e.g. NC1223 and 1425) provide these conditions.
4. Changing distributions Most of the species that occur in Assynt are at the northern most limits of their UK range. However there are fast moving changes occurring in the ranges of some species. Orange tips and speckled wood have been spreading in the North of Scotland and reached Assynt fairly recently. Isolated individuals of orange tips started appearing in Assynt in the 1990’s. Speckled wood have increased their range more extensively and only arrived in Assynt in the early 1980’s from further south on the western seaboard. They are now widespread in Assynt. Peacocks have also arrived but only since 2000. As climate change continues we may see more changes and therefore we need to continue to record distribution in detail and over time.
5. What to record in Assynt. Records are still patchy, especially from more remote areas, and the records we do have have been digitised – Assynt Butterfly Records. Take a photograph if you are in any doubt about the identity. If you are sending in a record, please supply a grid reference to at least a 1km square (e.g.NC1232), date, name of observer and any comments on abundance. Lists from a single locality, such as a garden, over a period, with dates of appearance and numbers, would be particularly useful. We are interested in good digital images of any species taken in Assynt.
Send any observations or photographs to us via the reporting form on our home page or by email to firstname.lastname@example.org.
5. Further information. The Highland Atlas mentioned above is the best introduction, and there is a wealth of books on British butterflies as a whole, up to the most recent definitive account The Millenium Atlas of Butterflies in Britain and Ireland (Asher J. et al, 2001), which should be available through your local library. .
Also there is a leaflet available entitled Butterflies of the Highlands – an identification guide produced and available from Butterfly Conservation Scotland
Members of the Field Club undertake butterfly transects each year for Butterfly Conservation, and also contribute records to national mapping schemes run by them. In addition, Butterfly Conservation Scotland has regular Newsletters, as does the active Highlands and Islands Branch. For more information on Butterfly Conservation please visit www.butterfly-conservation.org/313/highlands-and-islands-branch.html
Ian Evans (March 2010)