Discovering the Brown Hairstreak at Woods Mill
By Chris Corrigan
Chief Executive
Sussex is a county blessed with a wide variety of butterfly species thanks to the diverse range of habitats and landscapes in a warm and sunny (but not this year!) part of the UK.
The last of our resident butterfly species to emerge is the elusive Brown Hairstreak (Thecla betulae). Although it has striking orange underparts it can be tricky to find, but Sussex is one of the best counties for the species. This week, I was lucky enough to see one on our Woods Mill nature reserve which must be one of the best sites in Sussex to see one.
This is a species which spends most of its time high in the tree canopy. Males emerge first and gather in tall “Master Trees”, often Ash trees. The females will then emerge, head for the “Master Tree”, mate and wait in the canopy for about a week while their eggs to ripen before heading off in search of suitable egg-laying sites. This is the best time to see one, typically in the middle of the day, as the females come down to lay eggs on the Blackthorn (Prunus spinosa) food plant. It particularly likes young, suckering Blackthorn. The expanding field hedgerows at Woods Mill are a perfect habitat, as well as providing excellent nesting sites for Nightingales and Turtle Doves. However, when searching it is worth noting that this is very much a species of the West Sussex Weald so butterfly enthusiasts in East Sussex will have to head west!
Needless to say, because Brown Hairstreaks occur at low densities and are so elusive it is not easy to survey them. One of the easiest ways to locate their presence is a winter search for the white eggs on young Blackthorn, usually at the base of a spine or in the fork of a twig. It can take a while to get your eye in, and successful searches can take a long time, but with practice eggs can be easily found.
As this is now the peak season for Brown Hairstreaks, why not come and visit Woods Mill on the next warm and sunny day. With luck and patience, you should be rewarded with a sighting of this beautiful butterfly.
Comments
More photos of them please 🙏
05 Sep 2024 11:10:00
Have seen three recently and didn’t know what they were, so pleased to have the explanation.
Each one rested until I crept near and then flew off, in wave-like patterns, high along the hedge – very frustrating!
05 Sep 2024 15:54:00
Very tempted. Hoping for a warm sunny day this coming week.
Enjoyed success earlier this year tracking down re introduction of large blue in Somerset!
05 Sep 2024 20:26:00
In past years have seen one or two at Heyshott Down reserve which was good for other hairstreaks as well.
05 Sep 2024 21:49:00
I live in East Grinstead very near Worth Way. I have photographed Brown Hairstreak butterflies on the low shrubbery at this time of year so suspect that they can found all along Worth Way as we are about half a mile along it from EG station.
07 Sep 2024 08:26:00
Wow – after all these years I have at last seen more info which could help me find one.. I enjoy all the butterfly information and photos. I enjoy other things too, but this is the cream for me
09 Sep 2024 16:07:00
Encouraged by Chris’s report/information I managed to catch up with and photograph a fine specimen over at Sussex Prairie Gardens near Henfield ( 11th September). Thanks for the heads up.
11 Sep 2024 22:03:00