It’s time to Hunt the Hairstreak

Greyis butterfly with white lines and an orange dot, on a leaf.
Purple Hairstreak. Photo: Malcolm Wemyss

Dorset has four of the five Hairstreaks: the Green, the Brown, the Purple and the White-letter. The Green is out earlier in the year, but the White-letter and the Purple are out now, and we need help recording them for different reasons.

The Purple Hairstreak is probably our most under-recorded butterfly, as it spends a lot of its time up in the tops of trees. It is likely that a high proportion of woods and copses contain this butterfly, but our map of where it was recorded recently shows many more areas without it than with it.

Please go out and look at your local oak trees to see if you can spot it; the best time is late afternoon or early evening. You will need binoculars as you need to look up into the trees and see if you can spot small butterflies whirling in and out of the canopy. If you are very lucky, it may come down to feed on bramble flowers, but this isn’t very common.

White-letter Hairstreak on bramble flower

White-letter Hairstreak. Photo: David Simmonds

The White-letter Hairstreak is genuinely rare. Its caterpillars feed on elm, and the advent of Dutch Elm disease in the 1960s hit this species very badly. Like the Purple, it spends a lot of its time high in trees. Further information on looking for it, including details of previous sightings can be found here.

Both butterflies are small – much smaller than the Red Admiral, for example.

Both the Purple and the White-letter are on the wing in Dorset now, so please see if you can help us find either. Any possible sightings of the White-letter are needed urgently, so we can get someone to come and check them out.




Leave a Reply