The last week or so has seen the arrival of quite a few Comma butterflies at the reserve. These are the autumn generation and are looking very fresh, (see featured image, taken October 1st 2016 ) leading you to believe they have not been around long.
The life cycle of these butterflies is quite interesting: they emerge from hibernation in March giving rise to a summer generation, which can breed rapidly, leading to an autumn generation usually around September. At the Gravel Pits, however, the autumn generation has only been noticeable the last few weeks which may be typical for more northerly regions. Looking at butterfly records for previous years, the autumn generation also seems to be the more abundant of the two, with considerably more sighted than in the summer months. If you take a trip down the reserve, in the next few weeks, keep your eyes peeled when passing many of our bramble bushes.
It has been a disappointing year for butterflies so far, but there have been a few encouraging signs. Despite their low numbers, a male and female Large skipper were seen on the South Lawn on 18th June and a Common blue (see featured image) was found by Phil Reed on 19th June. There used to be a healthy colony of Common blues at the Gravel Pits, so this was particularly pleasing, after one was spotted last year.
Both the Gravel Pits and Sun Lane had established colonies but both seemed to die out quite suddenly. Birdsfoot trefoil (often known as ‘eggs and bacon’) is their foodplant and their absence was made doubly disappointing since Sun Lane has had this in abundance in recent years. The Gravel Pits can’t boast the same quantities, but there are now several good patches.
After a bit of exploring a small colony of Common blue was discovered just over the road from the Gravel Pits and, last year, one individual was spotted on the South lawn on several occasions – a small nick in its wings making it identifiable as the same butterfly. So if you visit either of the reserves any sightings will be gratefully received since the hope is they will re-establish themselves again.