Black Hairstreak and Heath Fritillary – A Day with Britain’s Rarest Butterflies

Today, Jenna, her son Harley, and I set out in search of two long-standing targets for our life lists: Black Hairstreak Satyrium pruni and Heath Fritillary Melitaea athalia. With weather threatening to intervene, we began the day at Glapthorn Cow Pastures in Northamptonshire, the county’s premier site for Black Hairstreak.

Managed by the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire, Glapthorn Cow Pastures is well known for this elusive butterfly. Although the species occurs throughout the reserve, the best opportunities for close views and photography are traditionally along the famed ‘third ride’.

On arrival, we were encouraged by a timely report from another visitor who had just seen the hairstreaks, and we headed straight for the third ride, mindful that rain could quickly curtail activity. Our concerns were unfounded: before long, we located a Black Hairstreak feeding low on Blackthorn, offering excellent views.

Several individuals were soon noted perched on flowering bramble, moving between blooms with their characteristic jerky flight. By the time we reluctantly left the site, we had counted at least six Black Hairstreaks—an excellent return for a species that can often test one’s patience.

Jenna and Harley on the third ride

With success secured, we made the two-hour drive south to Hockley Woods in Essex, one of the strongholds for Heath Fritillary, among Britain’s rarest and most localised butterflies.

Entering the woodland, we half-expected a prolonged search, but optimism rose as we reached the first suitable clearing. 

As we spread out to scan the area, Jenna called out that she had found one—quickly followed by two more. The sudden abundance was almost unbelievable.

The Heath Fritillaries showed superbly, allowing prolonged and close views, as illustrated in the accompanying photographs. After a day that had exceeded expectations at both sites, we headed home reflecting on a memorable outing. Our British butterfly total now stands at 59 species—a satisfying milestone capped by two very special insects.