Black hairstreak

Scientific name: Satyrium pruni

The black hairstreak is a rare butterfly that is restricted to woodlands and hedgerows containing blackthorn - the foodplant of the caterpillar. It is both elusive and hard to tell apart from other hairstreaks.

Species information

Statistics

Wingspan: 3.4-4.0cm

Conservation status

Protected in the UK under the Wildlife and Countryside Act, 1981.

When to see

June to July

About

The black hairstreak is the UK's rarest hairstreak, but is more widespread in Europe. In the UK, it is only found in mature woodland and hedgerows in the East Midlands, Oxfordshire and Buckinghamshire. This species does not travel or disperse over great distances.
Adults are on the wing for a short period over June and July, but are very elusive, spending much of their time in dense blackthorn scrub or in the canopy where they feed on honeydew secreted by aphids. Blackthorn is the main foodplant of the caterpillars.

How to identify

The upperwing of the Black hairstreak is brown with orange spots. The underwing is brown with an orange streak. There is a row of black spots near the margin and a thin white streak across the underwing. It is very similar to the white-letter hairstreak and these species are extremely difficult to tell apart while in flight.

Distribution

Restricted to parts of the Midlands and South East England.

Habitats

Woodland

Did you know?

Caterpillars go through a serious of moults, called 'instars', before they mature, often looking quite different each time. The older caterpillars of the black hairstreak bear a striking resemblance to the blackthorn leaves on which they feed - a great form of camouflage.

How people can help

The Wildlife Trusts manage many woodland nature reserves sympathetically for the benefit of all kinds of butterflies, including the speckled wood. A mix of coppicing, scrub-cutting, ride maintenance and non-intervention all help woodland wildlife to thrive. You can help too: volunteer for your local Wildlife Trust and you could be involved in everything from traditional forest crafts to surveying for butterflies.