Michael Walter's latest report:
Heath fritillary numbers peaked at around the 15-year average of 400, but this was well below the figures for four of the past five years, and the cool spring weather doubtless contributed to this decline, causing the caterpillars to develop more slowly and so be vulnerable to predation for longer. No new colonies emerged this year, but several of the old ones inevitably vanished as coppice growth shaded out their foodplant, the yellow-flowered cow-wheat. Unfortunately, I failed to fully survey one site for much of the season, not realising until some days after the peak that the butterflies were flying over a far wider area than just where the cow-wheat was present. Consequently, I don’t actually know how large that particular population was, but extrapolation from figures for a neighbouring colony suggested that the mystery site must in fact have been the biggest reserve colony this year, with a peak of around 80-100. This colony was in young coppice, in which populations can build up far more quickly than in rides and glades where most of the other colonies occur, so carefully targeted management this winter may well ensure that the colony increases over the next few years.
As for the other butterflies, ringlets look set for a bumper season. Often casually dismissed as boring old brown insects, ringlets areactually rather glamorous, with the dark chocolate-brown upper wings smartly set off by a narrow white border, while the underwings sport a splendid line of eyes – white pupils surrounded by black irises encased in an outer ring of exotic gold.Recently I’ve had quite a few sightings of white admiral and silver-washed fritillary, two of the more exciting species that are getting re-established on the reserve, having disappeared altogether in the mid-twentieth century.
On the breeding bird front, there were few great surprises. A turtle dove that sang for a while in an area next to the small heath appears not to have stayed, so this may be yet another year with no recorded breeding. Curiously, though, one has been seen and heard purring from phone wires along the Rough Common road this spring, close to the post office – a far cry from the scrub and farmland normally occupied by these summer visitors. A favourite food is the seeds of fumitory, a rather delightful little magenta, pink and white flower that was formerly an abundant arable weed. The advent of herbicides mean that it, along with cornflower, corn cockle and many other attractive flowers, are no longer the commonplace species that they once were. However, an apple orchard near Chartham Hatch that was grubbed out last winter was suffused with a purple haze in June due to the proliferation of countless thousands of this lovely flower and, as it happens, a pair of turtle doves are resident very close to this field, so they may now be gorging on ripening fumitory seeds.
Nightjars appear to be down to just three pairs, and marsh tit and spotted flycatcher numbers were also disappointing. Although there were only seven pairs of bullfinches, this is in fact rather better than in most recent years. You might think that a species with a pure white rump, and a male with a deep rosy breast would be rather conspicuous, but you’d be wrong. During the breeding season the bullfinch is a very retiring bird, seemingly embarrassed by its own bright plumage; it has the feeblest of four-note creaky songs, and can be remarkably difficult to detect while nesting, but, now that the young have fledged, the birds seem to be everywhere, flashing their rumps as they fly off into a thicket.