After all the rainy weather (I even found a large toadstool – in June: The Blusher, Amanita rubescens), today was suddenly hot, at least it seemed so while digging brambles out of the ramp meadow, raking up the scythed Cow Parsley in the full sun, pitchforking it into a barrow and carting it off to a deadhedge. It was a satisfying conservation job, one of those where you can see what you have done, and it looks a lot better after than before. The area is supposed to be a meadow; we successfully suppressed the overgrowth of brambles two years ago, leading to a burst of rather nice Garlic Mustard and its attendant Orange Tip butterflies last year: and a second wave of Cow Parsley that must have seeded itself really well, because it suddenly covered the area this year. Now that it’s all cut, we may hope that grasses and smaller herbs may get going: some Ground Elder at least has begun the process.
In the pond and on the vegetation for a way around it, including atop the hump, Large Red Damselflies are soaking up the sunshine, and flying in cop, egglaying – the females dip the rear half of their very long abdomens in the water to reach an aquatic plant such as Myriophyllum on which they place the eggs.
The butterfly transect was again quiet, but graced by the first Cinnabar Moth of the year: there is a fair bit of Ragwort coming up, and this adult must be newly hatched out of a pupa, presumably at ground level or below as the plants are annual.
Sure enough, after I had finished the transect, the first Holly Blue butterfly of the year, beautifully fresh and new, skipped its bright quick flight just in front of the hut.
With the light changing all the time in a showery airstream (and the Met. Office seemingly unable to get the forecast right for the last several days, wrong every time to my surprise), things looked hopeless for butterflies (just a Speckled Wood or two) and insects (a few leaf beetles, hoverflies and bees).
So we picked up a field guide and a couple of identification sheets, and went out to see what grasses we could find between three of us.
Perennial Ryegrass
Ryegrass is a tough grass useful in lawns. Its neatly alternating spikelets make it easy to identify.
Cocksfoot grass
Cocksfoot is a taller grass with a head that somewhat resembles the shape of a bird’s foot with its chunky branching spikelets to left, centre and right .
Soft Brome grass
Soft Brome is as its name suggests soft to the touch; its spikelets like most Bromes are compactly plump and rounded, they form a pattern of green and white stripes, and they have awns (little barley-like spines). It’s quite distinctive once you’ve seen it.
Barren Brome grass
Barren Brome looks very different: perhaps its name comes from the way it appears to have nothing much in its seed-heads, which are thin, triangular and very spiky; the plant is altogether long and thin and dark purplish-brown.
Yorkshire Fog
Yorkshire Fog, a beautiful name for a lovely soft plant, is thick and tall with broad soft leaves and a remarkably thick, soft seedhead. It’s one of those plants you can recognise twenty yards off once you know it.
The reserve has some False Oat-grass which in theory we should be pulling out – it seem unlikely given the way it’s tightly integrated with the rest of the grasses and herbs, so it’s probably here to stay.
There seem to be several Fescue grasses in the thin strip of acid grassland along the line of the old railway – the clinker that the sleepers rested on consisted of chunky angular chips of hard acid rock from somewhere far from London. One is Sheep’s Fescue: there may be Red Fescue, and there is something that looks like one of the taller Fescues too.
Rough Meadowgrass
The Meadowgrasses have a typical light open panicle for their seedhead, giving a rather delicate appearance with their slim stems. I carefully checked which kind this one was; it has a pointed ligule where the leaf joins the stem, and is gently rough with little hairs, so it’s the Rough Meadowgrass.
Rough Meadowgrass
In the woods near the path there are tufts of a broad-leaved grass that tolerates shade: it’s the Wood Melick. Finally, there’s one conspicuous grasslike plant that enjoys the wetter places here: the Pendulous Sedge. It’s a bit invasive but so handsome that I always admire it.
Saturday 31 May was Bugs Day at Gunnersbury Triangle. The team arrived early to set out home-made cakes, lemonade, a face-painting stall, tables for children to paint butterfly cut-outs, signs advertising the day, and a wall-sized display of the Tree of Life, or rather a Tree of Invertebrate Phylogeny.
Paint that Butterfly!
Throughout the day a succession of families with small children came and had fun decorating the butterflies.
Tool Shed as Tree of Life
The Tree of Life occupied a whole wall of the tool shed.
Worm survey
For the first time, we carried out a worm survey, organised nationally by Riverford organic farms (there’s a free identification guide to print out) – bizarrely, there is no map of the distribution of our native earthworms, so perhaps in a year or two there will be one now. We found no ordinary Lumbricus terrestris (Lob worms), the big ones that burrow deep under lawns (, maybe we needed to dig deeper), but good numbers of Black-headed worms (Aporrectodea longa, dark head, brown body, long and thin), a few smallish Green worms (Allolobophora chlorotica), and a Grey worm (Aporrectodea caliginosa, grey with a pink head and a pale saddle). It was surprising how many individual worms there were in a spadeful of earth, and the number of species. Darwin showed how important the earthworm was, but they seem to have been quite thoroughly neglected ever since.
Bug walk
An entomologist from the Natural History Museum led a guided walk on the bugs to be found in the reserve.
Polymorphism in White-Lipped Land Snail
We gingerly plucked banded land snails from some tall stinging nettles, finding a good range of colour varieties from clear yellow to heavily striped with dark brown and black.
Woodland bug hunt – slugs, centipedes.
In the woodland, the entomologist boldly ventured outside his special area (Diptera) to familiarise visitors with the range of local slugs, centipedes, millipedes and woodlice: bugs in the very broad sense. We did have some true bugs too: shield bugs that give off a warning stink when held between finger and thumb. And in between, ‘bugs’ often means insects in general.
CentipedeLarge Sawfly (Symphyta, as no waist)
The sawflies and ichneumon flies are difficult for non-experts as there are hundreds of similar species and no popular books. However, the sawflies have thick cylindrical bodies, whereas the ichneumons, like the social wasps, have a very narrow ‘waist’. The Hogweed flowerheads (very large white umbels of dozens of small flowers) played host to plenty of good big sawflies with yellow legs and waspish black-and-yellow stripes.
Nice side/tail view of Cuckoo Bee on Hogweed
A keen amateur entomologist (who recalled visiting the Triangle before it became a reserve 31 years ago) found this Cuckoo Bee. It parasitises and resembles ordinary bumblebees such as Bombus hortorum, but it never makes a nest or raises young. Instead, the females enter a bumblebee nest that already has a good number of worker bees, displace their queen, and lay their own eggs. Their brood is then brought up by the host workers. It’s a nasty way of life. The adults have a rather distinctive ‘tail’ with less ‘fur’ than usual.
Tree Bumblebee, a rather recent immigrant from northern Europe, now common in the reserve
The Hogweed was also feeding plenty of Tree Bumblebees, a smallish species with a bright orange-brown furry thorax and a black abdomen tipped with white, so they are distinctive and easy to recognise. Only ten years ago or so they were unknown in England, but common just across the channel. They seem to have arrived all by themselves – bumblebee expert Dave Goulson (see Book Reviews) found them by chance in the New Forest – and now they are common here. Perhaps their northward spread is part of a global drift of species and habitats towards the poles as the climate warms.
Micro-moth Nemophora degeerella – longest antennae of any UK moth
The entomologist found this beautiful micro-moth, giving the lie to any idea that they are all small and brown. Nemophora has a bold yellow-orange stripe across its forewings, making it instantly recognisable, but even more impressive are its antennae, which are over 4 times as long as its body (fw: 10mm): the longest antennae of any British moth. Quite a surprise.
I had a go at the ‘regular’ butterfly transect down at the reserve. It was warm and humid but overcast and it didn’t look promising. A large willow covered in Gypsy Moth caterpillars had been loosened by all the rain, and had fallen across the path. I lopped off the crown branches and carted them down to a dead hedge to fill in a gap someone had been climbing through.
The sun peeped out and the cloud cover reduced to maybe 60%, making it warm and pleasant. A single Small White appeared over the ramp and made it onto the transect. I wandered around the reserve, but there was nothing until I found a solitary Speckled Wood in the large meadow.
However, there was plenty to notice all around. The building site looks a lot better now the ‘Costa Concordia’ white horizontal balcony cladding on ‘Chiswick Point’ (well, it’s in Acton Green and on Bollo Lane, but I guess Bollo Block didn’t quite have the same cachet) has been completed: it will be nice when the noise of cranes and drilling stops.
Handsome iridescent green male Oedemera nobilis on Catsear
Many ichneumon flies were out on the Hogweed, some mating; almost every Catsear flowerhead had one or two handsomely iridescent green Oedemera nobilis, the “thick-kneed flower beetle” – only the males have the swollen hind femurs, but both sexes have a gap between the slender wing-cases. The males were of noticeably varying sizes, presumably the large ones having the best chances of mating.
Tent of Peacock butterfly caterpillars on Stinging Nettle
A fine bustling mass of hairy black early-instar caterpillars of the Peacock butterfly, wriggled on their silk tent atop a Stinging Nettle.
Laburnum leaf beetle larva doing an impressive amount of leaf damage
The Laburnum by the main path is being eaten full of holes, probably a good thing for a non-native shrub in the reserve, by spotted and striped larvae of the Laburnum Leaf Beetle. Never seen it before.
Mating Rose Sawflies
The wild rose in the car park hedge was host to a mating pair of Rose Sawfly, a serious pest for gardeners but an attractive insect with a bright yellow abdomen.
Large Red Damselflies in cop over a lot of healthy Starwort in the pond
As if all these treats weren’t enough, there were Large Red Damselflies mating and egg-laying on the pond, Common Blue Damselflies, lots of Hoverflies, Click Beetles (seemingly Athous haemorrhoidalis), large brown frog tadpoles and small black toadpoles, singing Blackcaps, a Song Thrush, a Jay, and plenty more. Maybe it’s not just Bugs Day on Saturday, but Bugs Week.
On a grey rainy day, I put on my waterproofs and go down to the Gunnersbury Triangle reserve. A newly-fledged Green Woodpecker flies off. The cow parsley has taken over the whole of the meadow by the approach ramp; last year there really wasn’t very much of it, but now the tall white umbels are quickly turning to seed-heads across the whole area: they need to be pulled up quickly before they ripen. They are accompanied by quite a lot of cleavers (sticky-grass), nettles, hogweed, even hops twining their tall fibrous way over the other plants. And a few brambles are coming up again: we had a blitz a year or two ago, pulling out most of them, and the meadow is much improved, but that hasn’t saved the rather nice garlic mustard (good for orange tip butterflies) from the cow parsley invasion.
I loosen one bunch of roots after another with a fork, and pull up the cow parsley roots – much like carrots, they’re in the same family. When the soil is shaken off they are a pale brown, some straight and carroty, some branched into five smaller swollen roots. When I have a big armful, I carry them down to the dead-hedge.
Digging again, a nettle manages to sting me lightly through the leather-and-cloth gardening gloves. I hear a screaming sound and look up: eleven swifts are wheeling together high overhead, the most I’ve seen over this part of town this year, indeed for many a long while. Sixty or more sometimes gather over the lakes at the London Wetland Centre, pausing to feed before moving on up north on their spring migration.
I gather another armful of cow parsley. The meadow is starting to look a little better. I pull a six-foot stick out of the herbage; half-a-dozen diversely coloured white-lipped land snails, some plain yellow, some striped with black, fall out on to the path. The polymorphism has been argued over by ecologists: it might be camouflage adapted to different backgrounds, some lighter, some darker; or more interestingly, it might be a way of defeating predators like Song Thrushes which could be searching for snails of a particular pattern, so if a bird had learnt that snails were striped and had that ‘search image’, that bird might not spot plain snails, perhaps.
It comes on to rain. I help out in the hut, making preparations for Bug Day when we hope the reserve will be buzzing with excited children and their parents. They will be welcomed by a smiling ‘GunnersBee’, who is a black-and-yellow cutout on a huge blue card with yellow cutout flowers. Even in the drizzle, several species of real bumblebees are busy gathering pollen and nectar.
Yes, it’s ornamental cherry time again. Sitting at the breakfast table with a coffee, I watch two male Blackbirds perch on the garden table and chairs under the tree. One flies up, hovers for an instant, lands, and can be seen to have a small black cherry in its propped-open beak. It swallows, looks up, repeats the cycle.
There is a Blackbird nest exactly in the middle of the ornamental cherry, atop the end of a cut branch; it is not very well hidden from anyone walking in the garden, nor very far from night-prowling cats.
Less welcome are the Wood Pigeons that noisily flap into the tree’s slim branches, finding a wobbly perch before greedily guzzling the tiny cherries, the first fruits of the year. If they become numerous they will threaten to devastate the crop of real edible cherries from my ‘Stella’ tree. Stella is a good deep red variety, not as dark and bitter as Morello (but a great deal sweeter), though rather on the late side. The pigeons, of course, find it delicious. I always had to cover the tree with nets, until last year when there was hardly a pigeon or even Blackbird to be seen near the tree: I suspect a bird-killer cat used to lurk on the shed roof at night and stalk its avian prey.
Out the front, another bird-only cherry grows in the pavement. It is risky to park the car beneath it, the birds – mainly starlings – spotting roof and windows with rich purple-red stains made gritty and corrosive with white powdery uric acid.
Leaf miners in Spinach Beet leaf. A strip of the leaf’s upper epidermis has been torn back.
Well, I usually try to take a pretty picture to start off a posting, but this one certainly doesn’t qualify. These leaf miners grow entirely inside a leaf, in this case of Spinach Beet. As you can see, as they grow they tunnel around below the leaf’s upper epidermis, which is a translucent layer of cells, leaving it intact to provide themselves with a ready-made cover.
Underneath that sheet, a healthy leaf contains a thick green set of palisade cells in one or several layers. These are the leaf’s (and the plant’s) factory, as they are full of chloroplasts, coloured green to absorb light: they synthesize the sugars on which life depends.
Not many people would want to eat this leaf, once the leaf miner larvae – mostly moths – have been at work. The palisade layers are entirely and efficiently destroyed wherever the insects have been. All that remains is an air-space and some dark frass: all, that is, but for the plump whitish cylindrical bodies of the larvae themselves.
Ladybird larvae and eggs on Spinach leaf
Also nesting on the spinach are some ladybirds. These have incomplete metamorphosis, the young being able to walk as well as eat from their first stage or instar. Each time they moult they change in appearance as well as in size. They mainly eat aphids, troublesome pests of many crops, so they are useful to gardeners and to any farmers who don’t want to use insecticides.
Shield Bug on Spinach
This shield bug, seen here in close-up, may look conspicuous enough, but that is the camera’s view. The insect is actually rather well camouflaged, and it generally hides under a leaf where it is in some shadow. The camouflage consists first of a general colour resemblance to its background, with its overall grass-green coloration; and as seen here, it is also disruptively patterned, with the reddish brown of its wings tending to break up its outline. Perhaps it is also somewhat countershaded, with dots stippling its back. Bugs suck plant juices, and their larvae can be quite destructive, but they never seem to do much harm to the spinach.
There are also some green caterpillars, excellently camouflaged with a pale cream stripe all along their sides. (It might be the Hebrew Character moth.) You might expect this to be conspicuous, but it seems to be a classic piece of disruptive coloration: the stripe appears like a sun-glint specular highlight on the shiny crumpled surface of the spinach leaf, rather than part of a solid, round-bodied animal.
A Sawfly … not on Gooseberry
A pest I know is there is the Gooseberry Sawfly. There are numerous sawflies in the garden right now, but they are all flying around the Nasturtiums, nowhere near the gooseberry bush. However… plenty of the lower leaves of the gooseberry are badly damaged by sawfly larvae, some eaten right down to the petiole, pathetic little stumps with a few short branching veins all that remains of once green foliage. What to do about it? This isn’t a how-to-garden site, but inspect your gooseberry bush(es) regularly, looking especially at the lower leaves to see if they’re being eaten. If some are, check the edges for caterpillars. If you find any, spray the bush after sunset on a dry still evening (to avoid killing the bees that are pollinating your fruit) with a garden insecticide.
Five minutes of careful searching of half-eaten gooseberry leaves failed to reveal a single larva. The cause in this case is not so much camouflage as the incredibly intense predation by Blue Tits (and Great Tits). I estimate these little birds are a hundred times better at finding caterpillars than I am. They have the advantage of getting in close – they must be able to focus down to a few centimetres, their small eyes acting as short-focus wide-angle lenses – and of being able to perch anywhere in a bush. They also get up very early, and know instinctively exactly what food looks like: small well-camouflaged caterpillars on the undersides and edges of leaves.
Zoologists suppose that birds have a ‘search image’ of the prey they are hunting: perhaps this is much the same idea as the training images that computer scientists use to teach their neural nets to recognise patterns such as faces. Once you have such an image in your brain, you almost instantly recognise your target when it appears. To give a small illustration, I remember when I had a small motorbike, I always saw bike shops everywhere; now I never notice them. My eye was attuned, like a Blue Tit’s to a caterpillar.
Heath landscape at Thursley with birch scrub, scattered pines
Thursley Common is one of those few, special places where the quiet visitor is almost guaranteed a beautiful experience of nature, at least if busy weekends are avoided. The area of a few hundred hectares offers several habitats, all acid: pine forest; dry sandy heath with heather, gorse and birch scrub, ideal for Whitethroats and Stonechats; acid bog with sphagnum, bog-cotton, marsh orchid, round-leaved sundew; bog pools buzzing with dragonflies; open water with teal and tufted duck.
Marsh Orchid, Round-Leaved Sundew at its foot, Thursley CommonDragonfly habitat: bog pools at Thursley; in the background, white of bog cotton, birch scrub and pine forest
Over the pools were half-a-dozen swallows in a loose flock, mostly flying high, keeping a wary eye out for hobbies. Two hobbies at least flew across the heath on their long grey wings, diving at speed to snatch dragonflies low over the water. A cuckoo called from the pines; another replied cuck-uck-oo from the other side; one flew hawklike across the heath, its wings remaining almost entirely below its body, an odd and very distinctive flight pattern.
Female Four-Spotted Chaser basking over a bog pool, Thursley
Four-Spotted Chasers have a distinctive jizz, being generally brown, flying fast, and indeed the males aggressively chase off rivals. Today there were several pairs mating in flight; unlike many other dragonflies, they do not settle to form a “wheel”, but soon separate, the female at once starting to lay eggs, darting down to the water to dab her abdomen repeatedly.
Large Red Damselfly, Pyrrhosoma nymphula male on heather at Thursley
Large Red Damselflies were hardly in evidence near the water, but were around in small numbers on the heather, or basking on the boardwalk. Nearby, a pair of Reed Buntings blundered in and out of the bushes, the male handsome with his black head and white collar, singing his slow brief song. A Goldcrest squeaked its unbelievably high notes from the tops of the pine trees. A Tree Pipit’s repetitive but slightly random riff rang out again and again from somewhere in the same trees; the species, still marked by the book as ‘abundant’ (that’s a 2 not a 1, however), ‘breeds locally’ in places like this.
Bog-Cotton, Molinia
It is always a pleasure, too, to see the fluffy white seed-heads of Bog-Cotton. The thin fibres are too brittle to spin, so our native ‘cotton’ remains a symbol of wild and lonely places, from the mountains of Snowdonia to the Pennines. It’s a reminder of just how extensive the heathlands of Southern England once were, Cobbett’s “rascally heaths” famously extending all the way from the Marlborough Downs to the fringes of London. His opinion, loudly voiced in his Rural Rides, was that these unimproved lands were wasted, a sign of lack of proper agriculture. The Dig for Victory! campaign in the Second World War caused many areas of marginal land to be ploughed up, including acid heaths, alkaline chalk grassland, and neutral flowery meadows: all were lost by the thousands of acres in a desperate attempt to increase Britain’s arable production. That led, of course, to the surplus production of the Common Market years, the destruction of farmland wildlife accelerated by grants to grub out hedges, while the use of pesticides of all kinds created marvellously clean crops that even that old badger of a critical farmer, Cobbett himself, would have heartily approved of. The one small problem was that the crops were so clean that there were no wild flowers to support the bees that used to pollinate the fruit trees, the clover, beans and alfalfa, the cabbages and turnips and oilseed rape, the potatoes and vegetables that feed the nation. The cereals themselves need no bees, their grass pollen blowing in the wind: but the rest of the crops are tied to a more balanced ecology. Thus I meditated, even as I enjoyed a nostalgic glimpse of Molinia, the Bog-Cotton; and so it is that delight in nature’s beauty is tinged with sadness at the mess we’re in.
Tiny yellow clubs of Bog Beacon fungus, Mitrula paludosa, by bog pool at Thursley
I was delighted to see the small but bright yellow Bog Beacon fungus. It appears as small clubs with white stalks, and it only grows on dead vegetation in acid bogs. Its specific name ‘paludosa’ means ‘of the marsh’. A single Broad-Bodied Chaser dragonfly scooted swiftly across a small pond.
Stonechat on fencepost of Hankley Common training area near Thursley
Stonechat males displayed atop gorse bushes or fence posts, or dived into the bushes for cover, appearing nearly all black from above, with a bold white flash on each wing. Several young ones perched lower down in the gorse, much browner and more streaky than their fathers. They are rather few and far between on the Common itself; more on the training ground just across the road at Hankley Common. Like Thursley Common, the land has remained wild because the army needed it for training; so the Second World War both destroyed much of the wildlife value of our farmland, and saved some places from the general destruction.
Today I watched as a young East Asian family with a small child wandered carefully, heads bowed, through the bracken (Pteridium aquilinum), picking young not-yet-unrolled shoots known as fiddleheads — they do look rather like the curled ends of violins — for use as a vegetable. It is commonly eaten in Japan, China and Korea.
Bracken, including young shoots, is carcinogenic in animals, and herbivores like horses generally avoid it if they can. The main toxin is ptaquiloside. Richard Mabey’s Food for Free mentions bracken only once, to say that it is carcinogenic, and omits it from the main text. Some scientists suspect that the high incidence of stomach cancer in Japan is connected to the consumption of bracken.
It was chilling, on a fine hot day, to consider the danger that family were putting themselves in. On the other hand, if they select only young shoots, the dose is as low as possible — the plants have not had time to accumulate toxins in newly-grown parts. And all of us consume substances — sugar, salt, nitrates in ham and sausages, … — not to mention alcohol, which are certainly not good for us. Can you have a natural history of human beings? I can’t see why not.
Blue Tit Update: after several weeks of frantic activity by the two parent birds until yesterday, today the nestbox is empty and unattended. All the young and their parents have left. They aren’t in sight at the moment: most likely they are not far away, as a family party. There are no signs of predation, and nestboxes mounted high on a wall are in any case very good protection against all our common nest predators.
The English seem unemotional … except for their passion for nature
