June and July see the peak flight season of the Silver-studded Blue butterfly, and people travel a long way to see them. This year I led a number of guided walks on the reserve for various community groups, including:
These were in addition to an Open Day which featured a guided walk for the general public as well as the opportunity to see inside the former RAF control tower. Three of these walks took place in the evening when the butterflies can be seen roosting rather than flying. If your community group would be interested in a Silver-studded Blue guided walk, I am open for 2020 bookings – late June and early July are usually the best times.
Numbers of Silver-studded Blues this year were good, although not quite as high as last summer when the weather was more favourable. Of particular note is how they are faring on the areas where we are trying to restore former arable land back to heathland. The first area to be restored was the Hangars field in 2007, and the chart shows how numbers of Silver-studded Blues have increased on the all-species transect, whereby a set route is walked weekly counting butterflies in a 5 metre wide imaginary box, since it was established in 2009. You can see from this that it took a while until the Silver-studded Blues became established. First the vegetation had to germinate in the bare sand following the soil inversion, and then the area had to appropriate to be colonised by the Black Ant, Lasiusniger, before the Silver-studded Blue arrived in good numbers in 2016, a period of nine years. The second area to be restored, the East of Runway field, which was more problematic regarding the establishment of heathland vegetation, also took nine years before good numbers were evident in 2018. As regards the Corner field, we are only eight years on from the seeding and numbers there are relatively low, but we would expect to see significantnumbers there in 2020.
The pond continues to support species of dragonflies and damselflies, although overall numbers seem to be less than in the last couple of years. Here are photos of two species taken by Lucy Lewis in late July – Emerald Damselfly and Ruddy Darter, both mature males. Look at those beautiful blue eyes of the Emerald Damselfly! Uniquely amongst dragonflies and damselflies it holds its wings at rest at a 45 degree angle.
Moorhens bred in the pond this year, rearing at least three chicks, and we reckon that the bulrushes give them adequate cover for nesting. However there is a risk that the bulrushes could end up covering most, if not all, of the open water, and I would be grateful for any advice as to how best to control them. As often with many issues in conservation, there are swings and roundabouts. So we usually end up with a compromise, which in this case will be to try to control the spread of the bulrush across the pond whilst continuing to maintain sufficient bulrush cover for breeding wading birds, as well as for roosting dragonflies.
Butterfly Conservation, Prees Heath Common Reserve Volunteer Warden