The United Kingdom Butterfly Monitoring Scheme has just published a plan for improving the monitoring of Brown Hairstreak butterflies with a standardized system of egg counting. Ordinary Transect Walks do not record Brown Hairstreaks adequately so a standard plan is very welcome to those recording the species across England. Here in Dorset we have been allocated the following km squares where Brown Hairstreaks have been recorded in recent years:
- ST 72/13 near Lydlinch and ST 75/11 near Deadmoor.
Additional squares that are suspected to be highly suitable for the butterfly by statistical modelling include:
- ST 62/18 North of Sherborne
- ST 75/04 East of Melbury Park:
- SY 39/95 Near Whitchurch Canonicorum.
The plan is that we, the Dorset branch of Butterfly Conservation, survey and draw up at least one egg count route with a walking distance no more than two hours in each square. This count would be carried out once per year, preferably between the end of November and the end of mid December when eggs are easiest to find amongst the bare hedgerows but before the larvae hatch. Additional sections to the egg count route can be added to sample less promising habitat and make a comparison. Detailed guides of how to draw up the routes & to carry out the actual egg counts are provided.
Our annual Brown Hairstreak Egg search was carried out and well attended on Sunday 13th December where 20 volunteers, lead by Wren Franklin and Martin Warren, chief executive of Butterfly Conservation who began the hunt at 11.00am at our Alners Gorse Reserve near Hazelbury Bryan. The site is managed specifically with wildlife and in particular, butterflies and moths in mind and we are lucky enough to boast three Hairstreak species which can all be seen feeding together in late summer, if you’re lucky!
After a successful search, the hunt moved to neighbouring Rooksmoor at 1.00pm.