Sparrowhawk drives Squirrel from Nest!

The day looked unpromising for a nature walk, let alone a butterfly transect, but it was time to do one, so after a cursory tour to clip the worst of the brambles from the paths, we set off with clipboard and cameras to see what we could find.

Gasteruption jaculator Ichneumon on hogweed
Gasteruption jaculator Ichneumon, nectaring on hogweed

The hogweed, still in flower despite weeks of rainy weather that has caused many stalks to topple, was alive with flower beetles, bees large and small, and this magnificent Ichneumon wasp with its incredible ovipositor.

At first we saw only white butterflies, but a Comma was sunning itself, and a Speckled Wood had somehow survived the wet weather.

Strangalia maculata on bramble flower
Strangalia maculata on bramble flower

We saw two Strangalia maculata longhorn beetles taking nectar. They are Batesian mimics of wasps, looking in all truth only very slightly waspish, but perhaps young birds are put off. Or perhaps they do in fact taste foul.

We were just discussing the Sparrowhawks as we approached their nest tree when a commotion broke out along a branch, and a Sparrowhawk flew rapidly with its claws forward: a Squirrel raced away from the nest, hotly pursued by the angry bird; they leaped to the neighbouring tree and scurried up the matching branch out of sight. The Sparrowhawk broke into a loud excited chittering trill. We were all excited, laughing at the speed, the impossibility of reaching for a camera.

A Holly Blue flew over the pond, above several pairs of mating Azure Damselflies and a Yellow Iris now chewed right down to a semi-leafless state by the Iris Sawfly larvae.

Mating pair of Azure Damselflies on Water Mint
Mating pair of Azure Damselflies on Water Mint

Down at the Anthill Meadow, a single Small Skipper perched on an ear of Yorkshire Fog.

Small Skipper in anthill meadow
Small Skipper in anthill meadow

On the next ear was a male Bluetail Damselfly: they have emerged from the pond in the past week.

Bluetail Damselfly Ischnura elegans
Bluetail Damselfly Ischnura elegans

The wooden rail was sticky with snail pulp: a Song Thrush had hammered three snails open on the exposed woodwork, leaving shells and sticky patches behind.

Wooden rail as thrush's snail anvil
Wooden rail as thrush’s snail anvil

Two days ago I saw a Cinnabar moth in the Small Meadow. There is plenty of Ragwort coming up, so with any luck there will be plenty of caterpillars soon.

Cinnabar moth in the small meadow
Cinnabar moth in the small meadow

 

Wet Enough for Liverworts in the Pavement

Marchantia polymorpha in pavement
Marchantia polymorpha in pavement

Well, it’s been pouring. The English Summer app is running, sort of, only the running is as in “running water”. The pavements in my street are wet enough to support flourishing colonies of the greenhouse liverwort Marchantia polymorpha. It is named polymorpha as it has many (poly-) forms (morph-). Two of these are rather splendidly visible in the photo.

Firstly, the female plants have decorative little umbrellas with star-shaped tops, which are gametophores which carry the female gametes, the ova.The flat green thallus is lobed like a liver, which by the mediaeval doctrine of signatures was supposed to be God’s way of indicating to the herbalist that this was a useful medicine for the liver … no worse than the modern crackpot ideas that Ben Goldacre ridicules in Bad Science, I guess.

Secondly, sticking up from the top of the thallus (try the top right of the photo) are little circular cups containing gemmae, small discus-shaped blobs of tissue. When a raindrop (yeah) splashes into the gemma cup, the gemmae ricochet out and land a little distance away, ready to grow, asexually, into new liverworts.They do this so well that stream banks are often carpeted with the little plants; and so are greenhouse pots.

Male plants (not shown here) have circular gametophores instead of the female star-shaped ones. Quite a lot of fun and curiosity from a small corner of pavement, really. In a sufficiently wet year, of course.

Error 404 Summer not found… but bugs aplenty

Newly-constructed flood fences
Newly-constructed flood fences

Well, you probably don’t need me to tell you that this summer – yes that was Midsummer’s day we just had – has been a teeny bit wet.

Midsummer's day Full 'Strawberry' Moon
Midsummer’s day Full ‘Strawberry’ Moon, a once- or twice-in-a-lifetime event

We’ve had the car park flooded repeatedly in front of the hut, and two storm channels have eroded tons of soil down the bank towards the railway.

The British Summer compared to a failed install
Please try Spain: the British Summer compared to a failed install

Joking aside, we picked up some stout hazel poles and bundles of long slender binders, and sat at the top of the ramp with billhooks to sharpen the poles and cut them to length as withy-posts. We then hammered them into the very squishy mud of the main erosion channel, and did our best to weave the binders around them. They were a little dry and we heard a few ominous cracks, but in the main they wove in and out pretty well. We made two little fences with five posts each, leaving space for water to trickle below the basketwork, and indeed through it.

Scouring under flood fence
Scouring under flood fence

Last night there was yet another thunderous downpour, so this morning I went to have a look at whether our handiwork had helped. There was some scouring under the centre span of the front fence – overall, it looks as if the fences did a good job, but perhaps we need one more fence just at the front of the channel.

Female Stag Beetle in GT
Female Stag Beetle in GT

But happily, the bugs don’t seem to mind. I rescued this female Stag Beetle from a mat of weed in the pond: she seemed fine, holding on to my finger. She’s at least the third adult we’ve seen in recent weeks, so presumably many more have in fact hatched, a success for our loggeries and management approach.

Common White Wave moth Cabera pusaria (eats Birch)
Common White Wave moth Cabera pusaria

I’ve several times seen a biggish white moth rushing away to hide under bramble leaves. Today I managed to photograph one, which obligingly “hid” under a rhododendron leaf (yeah, we have some) and it’s the Common White Wave, Cabera pusaria. It likes Birch and Alder, so it must be living on our Birch trees here.

Male Sphaerophora scripta hoverfly
Male Sphaerophora scripta hoverfly

Mike instantly identified this handsome orange hoverfly as Sphaerophora scripta. It’s one of some 20 species he’s expertly noted in the reserve. A Volucella pellucens, the very large black and white species (with a pellucid whitish band on its abdomen, you really can see light through it) hovered unphotographably overhead.

A handsome orange hoverfly
Another smart orange and black hoverfly on Hogweed, Eristalis horticola, a new species for the reserve

The Hogweed with its large white flowerheads is proving extremely attractive to different species of bees (honeybees, Andrena, Megachile leafcutters), bumblebees (tree, garden, buff-tailed, and others) and hoverflies, including this smart orange and black one. Mike says it’s a male Eristalis horticola, a new species for the reserve. Yay!

These are some moth (geometrid?) eggs on the underside of an English Oak leaf.

Array of lepidopteran eggs on oak leaf
Array of eggs on oak leaf

Looking for Swifts near Chiswick Mall…

Little Egret by Chiswick Eyot
Little Egret by Chiswick Eyot

Today I set out between the showers to survey the Swifts, if any, near Chiswick Mall. Equipped with a map and instructions, I chose six viewpoints at road junctions, and cycled between them, keeping a sharp eye out. By St Nicholas’ Church, three House Martins wheeled overhead, but no Swifts.

Up the Mall, near Chiswick Lane South, one Swift hawked high over the river, as did a pair of House Martins, quite an encouraging sight:. There were six nests in good condition on Field House, and within a minute I saw two Martins fly in and out of a nest.

Down the beach in front of Chiswick Eyot, a Little Egret trotted up and down in the water, showing off its elegant figure and yellow feet, and stabbing rapidly at invisibly tiny fish.

Nil to report at Eyot Gardens, despite the handsome tall terrace of red brick houses that once held many House Martin nests. No malice had been shown the colony: probably the loss is due to the dangers of the Sahel (and the guns of the Mediterranean).

Round the corner in British Grove, I was surprised and delighted to see two Swifts overhead – quite high, twice the height of the buildings, so no indication of a nearby nest, but still nice to see them.

If you know of any Swift nests in the area or nearby, I’d love to hear from you!

 

Belle Noiseuse: Newly-Emerged Sawfly Drying its Wings

Newly-emerged Sawfly stretching its still-curled wings
Newly-emerged Sawfly stretching its still-curled wings

A miniature drama unfurled in my garden this morning, little streaks of orange and black sparkling in the sun as they chose places to land and sun themselves. They seemed to be newly-emerged, as they immediately stretched out their wings on landing: and if you look closely, you can see that the wings are not fully deployed, but are still soft and need to be puffed out quickly before they harden. If so, it’s remarkable that these little flies can take to the air in that condition.

La Belle Noiseuse
Emmanuelle Béart in La Belle Noiseuse

La Belle Noiseuse, the beautiful nuisance, roughly. Not the female sculptor in Jacques Rivette‘s 1991 film, starring Emmanuelle Béart, but a small sawfly. It’s a glorious little insect, shining in the sunlight, its deep orange-ochre abdomen contrasting with its black thorax and head, its legs elegantly banded black on orange, giving it a slightly waspish look in flight. (Indeed, it is presumably a Batesian mimic of wasps, benefiting by looking as if it might sting.)

Newly-emerged Sawfly detail
Newly-emerged Sawfly detail

But its nuisance value does not lie in stinging, but in its caterpillar-like larvae, which devour the leaves of gooseberries and can defoliate whole bushes.

Still, it’s a splendid sight.

Fine Crop of Insects Pollinating Hogweed at Gunnersbury Triangle

Macrophya (Symphyta) mating on Hogweed
Macrophya (Symphyta) mating on Hogweed: one of two mating pairs, and many individuals around in the warm sunshine this afternoon. Mating lasts for less than a minute, so the photographer has to be lucky and quick
Small bee pollinating Hogweed
Small bee pollinating Hogweed (flying between flowers)
Tiny speckled beetle pollinating Hogweed
Tiny speckled beetle pollinating Hogweed
Rose Chafer on Hogweed
Rose Chafer on Hogweed
Oedemera nobilis on Hogweed
Oedemera nobilis on Hogweed
Strangalia maculata longhorn beetle on Hogweed
Strangalia maculata longhorn beetle on Hogweed
Marvellously slender long-tailed Ichneumon
Marvellously slender long-tailed Ichneumon, on Hogweed of course (just look at that ovipositor!)

OK, and to end, one insect NOT on Hogweed, the Small China-Mark Moth, on a Reed. It and many others of its species were fluttering about the pond, where they mate and lay eggs in waterside vegetation. I was really pleased to get the camera so close to this attractive little insect.

Small China-Mark Moth
Small China-Mark Moth

Marsh Orchids, Downy Emeralds, Beautiful Demoiselles: Yes it’s Thursley Common

Marsh Orchid
Marsh Orchid

It was a cloudless morning, perfect for a walk around Thursley Common to look for dragonflies, other insects, birds, and bog flowers too.

The bog pools were surrounded by Marsh Orchids in lovely purple bloom.

A few lizards, one with a regrowing tail, sunned themselves on the boardwalks.

Masses of Black-Tailed Skimmers chased aggressively about the pools, along with a few blue damselflies and some Black Darters. Some Large Red Damselflies warmed up on the heather, well away from the pools.

Lizard regrowing tail
Lizard regrowing tail

A Curlew called (or is it sang?) its beautiful, melancholic mating cry, flying high, slowly, and holding out its wings in a distinctive curve: something like a small heron, but with its incredible long downcurved bill, and tail feathers spread showily. It’s a rare delight, not least because Thursley is the only place Curlews breed for many miles around.

Stonechats on dead tree
Stonechats on dead tree

Stonechats sang their brief grating song from conspicuous viewpoints all over the common, sometimes in little family groups.

A Tree Pipit gave a fine display of its song flight from a tall tree.

On a lake filled with Yellow Water-Lilies at the edge of the common, gigantic Carp lurked and splashed at the surface, and Downy Emeralds chased, seeming club-tailed.

Downy Emerald
Downy Emerald (I only got this distant reflection)

A Green Tiger Beetle whirred on to the path – a very strange flight jizz,  but easily recognized once close enough.

Green Tiger Beetle
Green Tiger Beetle
Scorpion Fly
Scorpion Fly

Perhaps the most tantalizingly lovely insect of the day, however, was this Beautiful Demoiselle, shining iridescent Lapis Lazuli blue against the delicate pale green of a birch sprig.

Beautiful Demoiselle on Birch
Beautiful Demoiselle on Birch

Bat Walk at Woodberry Wetlands

Huma with Daubenton's Bat
Huma Pearce of London Bat Group with a Daubenton’s Bat at London Wildlife Trust’s newest urban reserve, Woodberry Wetlands

The screech and clatter of the Piccadilly line train filled my ears as we rattled, mercifully quickly, deep below the city centre in London’s fastest and loudest tube line, on the way to Manor House.

I emerged into the grey urban jungle of the Seven Sisters Road, the cars whizzing past the fast food shops as if to escape as soon as they might. Hooded youths hung about the estate gardens in small disconsolate groups. Women scuttled past, heads down, on the grimy pavements. I consulted my map, strode eastwards as purposefully as I could, and crossed into Woodberry Grove.

Woodberry Down unpromising setting
Woodberry Down

The gleaming new towers of “Woodberry Down” rose on either hand, the street lined with clean young trees and gleaming black cars. Even the pavements were newly laid in handsome yellow-brown flagstone. It was evidently a shinier, more prosperous Manor that the developers had had in mind.

Woodberry Wetlands gateway
Woodberry Wetlands gateway

Around the corner lay the entrance to London Wildlife Trust’s newest reserve, Woodberry Wetlands. It too was carefully landscaped, and money (from Berkeley, Thames Water and the National Lottery) had evidently been lavished on the gateway itself, a cunningly strong rust-coloured hut of iron, the reserve’s name laser-cut right through the metal walls on both sides. The building straddled the New River, a natural moat; and the gatehouse had its own portcullis, in the form of robust iron gates, locked at night.

London Bat Group arriving for a night's trapping
London Bat Group arriving for a night’s trapping. The New River is in the background

Huma (of Vole Patrol fame) and two other members of the London Bat Group arrived by car, carrying two enormous Harp traps in big red ski bags. I helped them over the footpath gates, locked to keep people away from bird nesting areas in the breeding season, and they walked around the reserve to a good place under the trees to set up their traps. They are doing some trapping as part of the National Nathusius Project, to learn about that species’ ecology and distribution in Britain.

Woodberry Wetlands (East Reservoir)
Woodberry Wetlands (East Reservoir)

I walked along the broad new boardwalk to admire the reserve, a ring of reedbed and bushes around Thames Water’s East Reservoir. A Mute Swan dabbled peacefully; a few Mallard and Coot prepared for nightfall. I counted 66 Swifts whirling about the three grey towers across the water.

Woodberry Wetlands cafe
Woodberry Wetlands cafe

In an old Water Board building, elegantly converted to a cafe/meeting room, were waiting soft drinks and an excited crowd of the lucky few who’d managed to get tickets for the bat walk.

Huma ran in, a little late, but evidently excited by the result of putting up the traps. She quickly told us a little of the myth and truth about bats – they never get in your hair, they don’t really drink blood (well, vampires do exist, but they’re tiny, and they lap up a few drops of the blood of peccaries (wild pigs), unless humans cut down their forests, remove the peccaries, and then insist on lying with feet poking out of mosquito nets).

She introduced our local bats, too, painting colourful portraits of their respective characters.

  • The largest, the Noctule, is “military”, flying high, fast and straight, echolocating loudly on each downbeat of its broad wings, with sounds heard in a bat detector set to around 20 kiloHertz as “chip shop chip shop”, slow and regular. The Serotine is “funky” by contrast, with shaggy fur and uneven calls; the middling Leisler’s, a relative of the Noctule, is halfway between the two.
  • The small bats, the Pipistrelles, call at frequencies depending on their species: the Common “Pip” at 45 kHz, the Soprano Pip at 55 kHz, and Nathusius’ Pip (a migrant from Europe that Huma hopes may be here) at 39 kHz. All of them have a distinctive, low, jinking flight as they pursue their agile prey; and all, too, accelerate their echolocating calls into a feeding buzz or trill as they close in on their prey, getting more and more accurate positional information exactly when it is most needed.
Trying out the bat detectors
Learning how to use a bat detector

We picked up bat boxes, little miracles of electronics with a sensitive ultrasound microphone, speaker, and illuminated setting dial. They work by heterodyning the signal: that is, you guess or choose what frequency you want to listen out at, say 20 kHz (too high for nearly everybody’s hearing), and the device subtracts that from the signal received from the bat, if one is calling. The difference, if you have guessed close to reality, is a low frequency, say 1 kHz, which you can hear. If the bat is calling in bursts (which radar engineers call chirps), you hear those as patterns of clicks.

Listening out for bats
Listening out for bats

We went outside and fiddled with the controls. Clouds of gnats, and some nibbling to our ears and cheeks, as well as the whizzing Swifts, proved there was abundant insect food on the wing for any bats that might deign to turn up. Nothing.

Suddenly the air was filled unmistakably with the loud, distant, slow handclaps of a Noctule bat. The Germans fittingly call it the Grosse Abend-segler, the Great Evening-Sailor, as it strides boldly across the dusk sky. We saw no bat, however, just a few Swifts. Presumably the Noctule was far away, its calls detected by our sensitive electronics. We scanned the sky in hope.

And then there was one, plain to the naked eye. And another, and another, and yet more. Five Noctules at least whirled above our heads, uttering loud claps in chorus. With binoculars they looked exactly as you’d think, large batwinged shapes black against the still-glowing sky. Since I was on duty as a helper, I passed the binoculars around; and everyone who looked managed to see what we had come for, bats wheeling joyfully, plentifully, close by, in a London summer sky.

Huma with bat detector
Huma leading the bat walk

Huma led us on. Between the New River and the reedbed, with bushes and small trees all around, Pipistrelles darted and swerved, buzzed and clicked. They were harder to get in binoculars than their larger cousins, but it was possible. Heterodyned clicks and claps played a chorus all around. Excited fingers stabbed the sky. A Little Egret flapped slowly overhead, on its way to its night roost. The urban jungle felt very far away.

We were called forward in little groups to a gate to see the trapping. Huma came up and showed us a Daubenton’s Bat, her hands gloved against small sharp claws and insectivores’ teeth. The species is a specialist in hunting low over still water: it can scoop up insects from the water surface with a cunningly-designed flap, and if it should fall in, it can swim and take off again safely. The London Bat Group was carefully weighing and measuring the little mammals, and then releasing them. They were using a lure designed to attract Nathusius’ Pipistrelle: it also attracts Daubenton’s, hence the catches. But they did catch a female Nathusius’: Huma was delighted.

London Bat Group with their Harp traps
London Bat Group with their Harp traps. Bats strike the fine mesh and fall into the soft containers below. The bright reflections are of flying insects.

Let’s end with a closeup of the main photo. It’s not every day you see a Daubenton’s Bat face to face, let alone in a capital city.

Daubenton's Bat in hand
Daubenton’s Bat in hand

More bat walks are planned.

Twitter users can follow the bat study at #LondonBatGroup,
#WildLondon, and #Mostlybats.

Pipits and Peregrines at Portland Bill!

Thrift, Birdsfoot Trefoil on Isle of Portland
Thrift, Birdsfoot Trefoil on Isle of Portland

We had a fine airy walk in brilliant sunshine, cooled by a stiff northerly breeze, around the tip of the Isle of Portland. Underfoot was fine maritime turf and massive Portland limestone, dotted with tufts of pink Thrift and yellow Birdsfoot Trefoil. The sea sparkled blue and silver around a wooden sailing ship with four triangular sails. A pair of Gannets flew effortlessly down the wind, tilting their long black-tipped wings.

To the south, the fearsome tide-race splashed ominously as if some Odyssean sea-monster (Charybdis and its whirlpool?) lurked beneath: the tide there runs faster than a yacht can sail, one way and then the other. Jonathan Raban describes it wonderfully in his book Coasting, the feeling of rising alarm and then, going for it, being shot like a cork from a champagne bottle through the swirling water.

A Rock Pipit, its beak full of insect grubs, called urgently as we strayed too close to its nest. A Razorbill, improbably proportioned like a fat impresario in black tie and tails, flapped by on small rapid triangular wings.

Oedemera nobilis, the thick-kneed flower beetle
Oedemera nobilis, the thick-kneed flower beetle

We saw few insects – some bumble bees, some handsome Thick-kneed Flower Beetles glowing iridescent green on buttercups, later on one male perched on a pebble on Chesil Beach

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Yellow Rattle at Portland Bill
Yellow Rattle at Portland Bill

The best flower of the day was probably the Yellow Rattle, an odd-shaped parrot-beaked yellow flower with spiky leaves. It’s a member of the Figwort family (like the Eyebright, whose growth habit is similar though smaller), and a hemiparasite of grasses: an important plant, as it weakens the grasses, keeping them low and allowing in a wealth of other flowers. It was once common in our meadows and permanent pastures, but fertilizers and ploughing have destroyed over 95% of these, and Yellow Rattle and the rest of our grassland flowers are now all desperately uncommon.

Overhead, two Peregrine Falcons slid through the air, circling without visible effort. A pair of Ravens came by. Standing at the top of the western cliffs, Fulmars flew out from their cliff nests, circling on stiff wings.

Scarlet Pimpernel
Scarlet Pimpernel

A little patch of Scarlet Pimpernel by a gate again reminded me of how this once common weed of cultivation (and sand dunes – presumably it was pre-adapted to disturbed ground) has declined.

We left Portland and drove down the hill to the Chesil Beach, struck as everyone is by the enormous shingle bar that stretches miles from Abbotsbury to the Isle of Portland, forming a bar with the Fleet lagoon behind it.

Sea Kale on Chesil Beach
Sea Kale on Chesil Beach

A few handsome Sea Kale plants clung to the lower part of the landward side of the shingle, including this one on the edge of the car park. It is the ancestor of the domestic cabbage in all its varieties, from Broccoli to Brussels Sprouts, Kale to Cauliflower. It is itself (obviously) edible, though as a now-scarce maritime plant one wouldn’t want to pick any of it at all often.

 Sea Beet
Sea Beet

Nearby, the ancestor of another valuable food plant, the Sea Beet, origin of Sugar Beet, purple Beetroot, and Spinach Beet. The wild plant too is edible, though the leaves are small, thick, and leathery!