Michael Walters' latest report:
Butterflies have been very much to the fore in recent weeks, starting with a minor invasion of painted ladies; I qualify the influx as “minor” in order to distinguish it from the 2009 inundation that overwhelmed the countryside, when many millions of painted ladies reached our shores from north Africa. This migration is achieved by a succession of generation hops – adults flying part of the way, then laying eggs that eventually give rise to a fresh cohort of adults that continue the northward movement. By the start of July most of these butterflies had either died off or passed on through Kent, with few to be seen now. Hot on the heels of the painted ladies came an eruption of our special butterfly, the heath fritillary, which has enjoyed an extraordinarily good season; Cook’s Glade, a small clearing just off the concrete track into the wood from Blean village, was positively shimmering with the frantic wingbeats of, by my wildly inaccurate count, up to 455 of these rarities that hardly exist anywhere else in the country. I shouldn’t forget to mention a single green hairstreak seen in June. Scarce and thinly distributed in Kent, it occurs on chalk, where its caterpillars feed on rockrose leaves, but also on acid soil, where they munch happily on gorse and other plants. The upper surface of the wings is a dull brown, but the underside is a bright emerald green. When you stop to think about it, green is a relatively uncommon colour in the animal world, and where it does occur it is often not as a result of pigmentation of feathers, fur or, in the case of butterflies, tiny scales; rather, the green appearance is due to the sub-microscopic texture of the surface which causes diffraction of the light hitting it, in much the same way that an oil film, only a molecule thick, on the surface of water can acquire technicolour hues.
I never know when I might be about to add a new species of plant to the reserve list, but this year there have been several additions in one very small area where the main stone track crosses the stream. Two years ago a major new concrete culvert was installed there, strong enough to take the weight of timber lorries. As the crossing was built up above the original track level, some soil had to be imported to grade the track into the surrounding woodland. I have no idea where the soil came from, but it evidently arrived laden with buried seeds. New plants that I have noted there include caper spurge, hoary mustard, purple toadflax and weld, all species that are not native to this country, but have carved out a niche for themselves on brown field sites. Despite its flowers being green, caper spurge is actually quite a dramatic plant, with its pointed, hooded flowers and narrow leaves radiating off a tall, unbranched stem. Its seeds are very oily, leading it to be trialled as a possible biofuel. The whole plant is flooded with an acrid, toxic white juice, and so should not be confused with the completely different caper bush, whose flower buds are used in the eponymous sauce; I discovered the distinction to my cost when I briefly chewed, without swallowing, a caper spurge flower and spent the rest of the afternoon with an unpleasant burning sensation in my mouth! Hoary mustard has numerous, small, yellow flowers, while weld, though tall, is somewhat nondescript with its narrow spike of very small, creamy blooms. Only the purple toadflax, with a willowy wand of deep purple flowers, could be thought of as a conventional garden flower, but one with a propensity for hopping over the wall and making good its escape down the road.
A plant that seems to have done rather well this year is tutsan; more like a very small bush than its brasher cousin, the creeping rose of Sharon, it is a shy plant, turning up in ones and twos very sparingly in the wood but, unlike rose of Sharon, it is a true native to the UK. This year’s weather seems to have favoured its flowering, and it has put on a fine show of bright yellow flowers, cupped by reddish sepals, the red berries that gradually turn black just starting to develop.
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Purple toadflax escaping from a garden in Blean
Single caper spurge plant in Blean Woods
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