Thanks to volunteer Phil for this report and photos
Brown Hairstreaks – Looking Forward to Summer. Thursday 28th January
This might seem a strange subject for January but nevertheless very topical.
The brown hairstreak is a scarce butterfly and we are fortunate to have a colony on the reserve. The adult insects fly in late summer up to the end of September and are hard to spot as they prefer to feed on aphid honeydew in the treetops. However after mating the females descend to lay eggs on blackthorn bushes typically where new growth meets old. The eggs stay dormant over winter and hatch into caterpillars in the spring which then emerge as adults around late July.
Scrub and hedgerow management is an important part of the work on the reserve and it helps to know where the hairstreaks are laying eggs to avoid disturbance, but also where blackthorns can be safely be trimmed back to encourage the new growth favoured for egg laying. To help this work a party of volunteers and a few visitors led by warden David Andrews, set out on an egg hunt on a rare and glorious sunny morning. Soon we had normal visitors being intrigued to spot several people peering intently into bushes.
For people like me who are new to this activity spotting the eggs is hard as they appear as tiny white dots in ones and twos. Eventually however, most people managed to get their eyes attuned to what they were looking for, helped by the fact that a few of our volunteers had done this before and were able to put us onto some eggs quite quickly. It might be assumed that the eggs are simply tiny white blobs but this would be quite wrong. Under magnification they are revealed to have a beautiful intricate structure.
Eggs were found in a number of areas, notably by the zigzag path, Adder Alley and the path down to Nettley’s hide. The latter is very close to the “master” ash tree used by the male butterflies to congregate there and sally forth to win passing females. This ash tree is unfortunately now hollow and unsafe thereby forcing the closure of the path through the picnic area, but it is still alive and no-one wants to cut it down because of its importance to the butterflies.
After the success of this survey I am now hoping that this will be the start of a journey that will lead me to seeing the adult butterflies for the first time this summer.