The holy grail for butterfly enthusiasts is undoubtedly the purple emperor, our largest butterfly, scarce but probably massively overlooked due to its habit of spending much of its life wheeling above the tree canopy. So determined were the Victorian collectors to bag their specimens that some took to wielding nets on 30-foot poles in a bid to snare them on high. There are some known sites in west and north Kent for this prized species, with an outlier in Ham Street Woods, but there appears to be no history of its occurrence in the Blean woodlands - until now, when a recent visitor thought he had seen one on the reserve. His claim cannot be verified, so it may take a combination of luck and persistence for someone to establish the presence of this majestic insect. Immune to the allure of nectar-laden flowers, it does, however, have a penchant for the juices oozing from rotting corpses and faeces, leading some devotees to devise their own patented concoctions of vile ingredients, “guaranteed” to bring the emperor down to ground level, and one such brew may eventually lead to photographic proof of the presence of emperors in Blean Woods.
A bird that is seldom seen, and certainly doesn’t have a healthy population, is the nightjar. It seems that we have just one territory this year, whereas in the glory days not so long ago there could be as many as six. The evening of my most recent visit, undertaken when the wind was howling, didn’t seem very propitious, but soon turned up a bonus in the shape of a dumpy woodcock in its aerial patrol of the wood, emitting low grunts and hissing “pitticks” as it passed overhead. Despite the gale, we ended up with lovely views of the male nightjar, light as a feather, in dancing shuttlecock flight above our heads – a memorable experience. But even if you don’t strike lucky with hearing or seeing one of these wandering souls, you still have the fun of looking for glow worms on the homeward trip, when light has drained from the sky, and the other evening we counted 33 along the track verge. Not actually a worm, but a beetle, it is only the female that glows, and she can’t switch the luminescence on and off, but the light is emitted from the underside of her body so, until she twists her abdomen, the light is inconspicuous. Being wingless, she is utterly dependent on attracting winged males to her alluring light in order to mate. The males are actively on the lookout for the beckoning greenish light, and if you shine a torch on a female you can sometimes see several males crowding round her in the hope of being shown preference. Glow worm larvae feed on small snails, which are in short supply in Blean Woods, whose acidic soil contains little calcium with which the snails can build their shells. A shortage of prey may therefore explain why relatively few glow worms are ever seen in the wood, though numbers do vary considerably from year to year.
New species of plants are hard to come by after 38 years, but one that I hadn’t encountered in the wood before was a single specimen of Oxford ragwort growing on a pile of stone that was due to be used in filling potholes. Similar to the more familiar common ragwort, which is the bane of horse-lovers and seventh heaven for cinnabar moth caterpillars, it is rather shorter and bushier, with much narrower, strap-like leaves. Brought over to Oxford from Sicily in 1700, where it grew on the volcanic ash slopes of Mount Etna, it brooded in the botanic gardens for many years before making a bid for freedom during the Victorian railway-building frenzy, when the plant found the hundreds of miles of ballast being laid for the track very much to its liking. Since then it has consolidated its position, and is now to be found throughout England, where it is happiest growing in extreme environments, such as cracks in pavements, where few other plants can thrive.
My somewhat ghostly attempt at photographing a glow worm. You can just about tell
that the light is being emitted from several abdominal segments, and is strong enough
to be reflected off the nearby vegetation.
Oxford ragwort on a pavement just outside Canterbury
The magnificent, regal purple emperor
We spend 90% of net income on conservation, public education and advocacy
The RSPB is a member of BirdLife International. Find out more about the partnership
© The Royal Society for the Protection of Birds (RSPB) is a registered charity: England and Wales no. 207076, Scotland no. SC037654