Be quick to catch the streak

White-letter hairstreak by Ken Hayes

If you are seeking the elusive white-letter hairstreak that flies for just three weeks a year – there is only a week left.

The white-letter hairstreak, is a butterfly that has been spotted on a number of our reserves, but this year they have been abundant at Brockholes.

The white-letter hairstreak prefers to spend most of its time at the top of elm trees, where they breed in late May and June. Their pupae are around until July and then they fly over a three-week period in July and August.

They will fly down to lower levels to feed on privet and brambles but they are also very small and brown, so quite difficult to spot. A wingspan of 36mm makes them the size of a 50p piece when fully stretched out in the sunlight.

The underwings, which you see when they first land are brown with a white “W” streak. There is also a subtle orange edge to the tail end of the underwing. The upperwing is brown, shown when sunbathing.

The white-letter hairstreak has also decreased in numbers as food plants were hit by Dutch elm disease in the 70s, so it is great to hear they are on the reserve.

The Brockholes Butterfly Bush, close to the entrance of Red Scar Woods, has been a great place for butterfly spotters.

And the gorse Butterfly Bush will continue to feed our butterflies for months after the white-letter hairstreak has disappeared for another year.

Only this week we have seen comma, meadow brown, gatekeeper and red admiral on the bush, along with various bees, hoverflies and moths.