Category Archives: Natural History

Natural History

Mayfly, Damselfly hatch; 5 Warblers!

It was a lovely sunny walk today, spring in everything but temperature, in a fresh Northerly wind.

I was greeted at Wraysbury Lakes by a jumble of music, a loud and vigorous Garden Warbler competing with an even louder Song Thrush to pour out rich fluty notes in a confusing stream.

Suddenly the air is full of rising Mayflies with their long triple tails. The masses of Comfrey and Nettles are dotted with the iridescent blue of Banded Demoiselles, like slender dragonflies, and the clear green of the females. Also quite a few Azure Damselflies, the males brilliant blue with little cup markings at the base of their abdomens (Segment 2), the females green with little ‘Mercury’ markings in the same place. I think I saw a slender Sawfly, too; and quite a few bumblebees visiting the Comfrey. Just two butterflies, a Speckled Wood and a battered Red Admiral.

Canada Goose with Goslings
Canada Goose with Goslings

On the lake, a pair of Canada Geese watchfully escorting their fluffy line of chicks.

Further along, Blackcap, Robin, Blackbird; then a patch of Chiffchaffs; more Garden Warblers, then a few Whitethroats, making extraordinary wheezing and squeaking anxiety calls, and one in song flight; a little flock of Goldfinches; a few Willow Warblers, deep in the scrub, my first of the year. The May blossom is on time, the Hawthorns heavy with their white dresses. In clearings, Bugle, Forget-me-nots and Cowslips; a Red Campion.

In the sky, a Kestrel; a dozen Jackdaws; a Heron and a Cormorant; more surprisingly, a pair of Shelduck, rather big, rather white, with black wingtips and a brickred band across their chests. Four Swifts wheel past, race low over the hill.

Among the mares with their foals, a dozen Starlings making their rasping calls, feeding their newly-fledged young on the ground in the open or watching from the bushes; a French (Red-Legged) Partridge running rather than flying; a hen Pheasant flying in, her broad wings heavily loaded like the wide-bodied jets that roar overhead.

It’s utterly different from the heat earlier in the week, when I was down in Wiltshire, watching a Kingfisher flash along the river in Bradford-on-Avon, a Heron stalking fish in the shallows, a Horseshoe Bat among the bushes at dusk.

Natural History

Garden Warblers All Over Watlington Hill!

Prime Garden Warbler Habitat at Watlington Hill
Prime Garden Warbler Habitat at Watlington Hill, with Gorse, Blackthorn and Wild Cherry in bloom

The weather forecast said fine and warm, getting warmer each day. The chalk downs called, so I popped out to Watlington Hill to enjoy the spring sunshine and the birdsong. I wasn’t disappointed: I’ve never SEEN so many Garden Warblers, and I mean seen. Their full, rich warble came from every patch of scrub, sometimes two or three singing at once, and the still mainly leafless trees (the buds just broken) make them visible for once. In binoculars, they are almost evenly soft mouse-brown all over, slightly paler below for countershading, with the merest hint of a little half-collar of pale grey. Sylvia borin has been called “Sylvia boring” by birders, and it’s a good mnemonic, if not much of a joke. They don’t have the Whitethroat’s white throat or patterned tertials; they don’t have the Blackcap’s black cap, or even the Chiffchaff’s eyestripe. All negative descriptions: but their song is both lovely and readily recognisable.

Also singing were Chiffchaff and Blackcap, both in numbers; Blackbird, Mistle Thrush (conspicuously perched atop their respective trees, and calling loudly and ringingly to each other); Dunnock, Great Tit, Blue Tit, Robin, Chaffinch, Wren. From the woods, Jays screeched; a Pheasant called in the distance; a few Swallows caught flies overhead; Buzzard, Stock Dove, Wood Pigeon, Magpie, Jackdaw, and Carrion Crow were about.

The hill is on the west-facing scarp of the chalk (Cretaceous, obviously) of the Chilterns, dropping down to the Oxford Clay plain which stretches away to Didcot and Oxford in the haze. The chalk grass is closely cropped by rabbits, but constantly invaded by hawthorn, blackthorn, whitebeam and bramble scrub.

Dog Lichen, Peltigera canina, in chalk grassland
Dog Lichen, Peltigera canina, in chalk grassland, with rabbit dropping for scale

I was pleased to see some patches of the Dog Lichen in the low turf.

The shadow of a Red Kite passed over the grass, and I looked up. A pair of the long-winged, fork-tailed raptors drifted over the hill, swivelling their tails, their bodies perfectly streamlined and front-weighted like gliders.

Brimstone female
Brimstone female

As it warmed up, a Brimstone butterfly appeared, perching on the ground to absorb some heat from the sun. It is one of the most leaf-like of our butterflies, which would suggest camouflage: but they are conspicuous even with closed wings. Perhaps birds see them differently from us.

Natural History, Nature Reserves

Hoverfly Diversity at Gunnersbury Triangle

Criorhina ranunculi male, courtesy of Mike Fray
Criorhina ranunculi male, courtesy of Mike Fray

Well, at last it’s warm. The anticyclone is heating up the air nicely, a couple of degrees warmer each day. The air is buzzing with hoverflies, and luckily with Mike about, we can actually put names to them. This one, a really remarkable bumblebee mimic, is Criorhina ranunculi – nothing to do with buttercups (Ranunculus), but a species whose larvae live in rotting wood, and it does have an odd nose (rhino-). Quite an unusual species.

Myothropa florea, a wasp mimic hoverfly
Myothropa florea, a wasp mimic hoverfly

This one, Myothropa florea, is a much more typical hoverfly, mimicking a wasp. Mike says he’s recorded some 18 species in the Gunnersbury Triangle LNR.

Nomada cf flava male cuckoo bee
Nomada cf flava male cuckoo bee

This is a male Nomada cuckoo bee, a brood parasite of other bee species. Its jizz is quite wasp-like in flight, with a flash of aposematic yellow-striped abdomen looking distinctly worth avoiding. At rest, it looks much more like the bee that it is.

Andrena (broad-headed) bee
Andrena (broad-headed) bee

 

Andrena cf nigroaena on new Hawthorn leaf
Andrena cf nigroaena on new Hawthorn leaf

This honey-bee-like insect, in contrast, is obviously a bee, and not a parasite. If you’re used to honey-bees, you’ll notice it has a markedly short head, shorter than it is broad: all the Andrena genus are like this. The head can be short because the tongue is also short, the genus being adapted to short-tubed flowers, so evolution has economically saved energy on building a wastefully long head.

Tiny tadpoles in the shallows
Tiny tadpoles in the shallows

Down at the pond, the sun sparkled on the clear water; a newt or two lurked between the weeds; and dozens of tiny tadpoles wriggled in the shallows. The Mallard pair swam about just below us, greedily feeding. I hope they miss some of the tadpoles.

Women volunteers at work
Women volunteers at work

We hammered in a line of posts for the log hedge, to reduce the number of sticks finding their way into the pond.  The ground was rather stony in places, and the iron bar came in handy to break through the stony layer first.

As we did the butterfly transect (Green-Veined White, Brimstone, Holly Blue, Speckled Wood, Large White), we saw a Sparrowhawk swoop into a tree, whistling to his mate. So it seems they’re nesting here again this year.

Jo planting out cornflowers, poppies, climbing nasturtiums and foxgloves
Jo planting out cornflowers, poppies, climbing nasturtiums and foxgloves

Back at the ranch, Jo was planting out some nice-looking small cornflowers, poppies, climbing nasturtiums and foxgloves raised by the Chiswick Horticultural & Allotments Society’s greenhouse team.

Two days later, the Swifts arrived in the skies over Chiswick, bringing their screaming flight calls to announce summer.

 

Love of Nature, Natural History

First Swifts, Garden Warblers at Wraysbury

Mare and Foal
Mare and Foal

OK, it’s official, spring has arrived. It may be freezing in the North wind, snow may be forecast, but … this year’s foals look lovely, relaxing with their mothers in the sunshine.

Overhead, the first three Swifts of the year wheeled against the blue sky; a couple of Buzzards drifted past, one mobbed by a pair of Carrion Crows; a Kestrel hovered, moved on, hovered again.

Down below, Wraysbury’s Lakes are empty of ducks, the winter visitors long returned up to the far North. The bushes, however, are rapidly filling up with warblers. Chiffchaffs, Blackcaps, and for the first time this year, masses of Whitethroats (there must have been at least a dozen, wheezing out their scratchy little songs) displayed atop still bare thorn-bushes, one male even venturing a little song flight. Several Sedge Warblers chirruped, whistled and churred their complicated but not very harmonious song — avant-garde jazz with Ute Lemper, perhaps — and to my great pleasure a Garden Warbler gave out its marvellously rich, full, even, sustained warble from a dense Hawthorn. So it was a five warbler walk.

The prettiest bird of the day, however, was a male Linnet. After months of being drab and scruffy, he was in full breeding plumage, his head gray, his back brown, his tail crisply forked, and the band across his breast redder than a Robin’s orange, really startlingly red. Most of the time I think Lars Svensson’s marvellously detailed Collins Bird Guide is exaggerating in those too-beautiful colour plates by Killian Mullarney and Dan Zetterström — but its painting of a breeding male Linnet is exactly true. Red. So there.

Freshwater Clam at Wraysbury
Freshwater Clam at Wraysbury

While off the beaten track listening to the warblers, I found this 13cm long Freshwater Clam shell. It was considerably thinner than a marine clam, and handsomely greenish-brown. I had no idea there were such large ones here right by London. It looks very much like the Swan Mussel, Anodonta cygnea, given its size, and indicates that the water “is in tip top condition”. The Natural History Museum has seen a specimen 19cm long.

 

 

Conservation, Love of Nature, Natural History, Nature Reserves

Roe Deer at Fray’s Farm Meadows SSSI

Frays River
Frays River

Well, it isn’t every day one visits 3 nature reserves, but today I had a look at Hillingdon NHS’s Harefield Place LNR, London Wildlife Trust’s Frays Farm Meadows SSSI, and Denham Lock Wood to boot.

These are by London standards remarkably secluded and inaccessible, which is to say you need to know where to park and which way to walk, as there’s basically no indication on the ground until you arrive, and even the LWT website is misleading.

Whatever the reason, it’s a delight on a fine spring day to find woods alive with Chiffchaffs and Blackcaps, a pair of Greater Spotted Woodpeckers calling and chittering with excitement directly overhead (and visible  in the still nearly-leafless trees), the Blackthorn in delicate white clouds of new blossom, and a Roe Deer skipping away across the meadow, stotting slightly and flashing its “I’ve seen you, I’m running away, and I’m faster than you so don’t bother” white rump-patch. It’s what zoologists call an honest signal, something that benefits both predator and prey. The predator is saved a wasted chase, and the prey gets away without hassle to live another day.

Canada Geese overhead
Canada Geese overhead

I walked in on the Golf Course path, a pleasant trek down the hill, past the lakes and along the muddy track through the willow woods. There are only our resident wildfowl at this time of year – Canada Geese, Egyptian Geese, Coot, Moorhen, Mallard, Tufted Duck, Mute Swan, Great Crested Grebe: presumably all breeding right here.

The track was studded with deer slots, and it was nice to have my “Roe Deer” slot identification confirmed with a broad-daylight sighting. Out of the woods, it grew hot, and I discarded coat and pullover.

An early Peacock butterfly
An early Peacock butterfly

A few butterflies flitted about – Brimstone near the brambles, a Meadow Brown or two, several Peacock.

and a Vole Patrol poster
and a Vole Patrol poster

I met another LWT volunteer, Daniel, who it turned out was not only checking the local boardwalks, but had got up at 5:30 am to do the Vole Patrol on his local patch here! I said I volunteered at Gunnersbury Triangle, and he said he knew who I was, he read my blog (Hi Daniel!). We talked of Kingfishers and conservation and being bitten by small mammals. He asked me which group I particularly liked, birds, butterflies? I said dragonflies, but it was a bit early for them. Sure enough, a minute later, a damselfly flew past! I got my binoculars on to it but had no chance to identify it to species (Large Red is our earliest, but I saw no colour). Still, a distinct surprise so early in the year. Perhaps they are hatching earlier with the warmer climate.

On the way out, I passed a Vole Patrol poster. Huma, the small mammal expert in charge of the project, really can’t be getting a lot of sleep travelling all over West London like this and trapping every day.

I walked across to Denham Lock, an attractively rustic spot with a line of narrowboats, traditional wooden lock gates and a delightful lock-keeper’s cottage complete with teashop.

Denham Lock
Denham Lock

A pair of Grey Wagtails flew about as if they owned the place, landing in the trees beside the canal, a few steps from where I took the photo. They must be breeding here too.

 

Natural History

Spring Surprises: Treecreeper, First Swallows, Ground-Nesting Heron

Ground-Nesting Heron a la Swan
Ground-Nesting Heron a la Swan

Spring is full of surprises, and this Heron, nesting not in a colony up in the trees, but all alone in an abandoned Swan’s nest in a reedbed, is certainly one of them. The London Wetland Centre this morning also boasted a mass of Blackcaps in the “Wildside” woodland, with at least three males and a female actually in sight at once,  along with an obliging Chiffchaff giving me an excellent view, and a characteristically invisible Cetti’s Warbler, shouting out its amazingly loud call. The Silver Birches were in wonderfully fresh green leaf, their bark crisply white against the clear blue of the sky.

Red-Breasted Geese
Red-Breasted Geese
Birch in Fresh Green Leaf
“Birches in wonderfully fresh green leaf”

Yesterday, round at Wraysbury Lakes, the same set of three warblers sang, but more elusively. The most delightful surprise was a Treecreeper, not only creeping up the willow branches, but singing its sweetly plaintive little song. This used to be rendered, rather tweely, as “Tree, tree, tree, once more I come to thee”, which does capture the length and rhythm of the song. It is not unlike the Chaffinch’s song, if you know that, but without the twiddly “tissy-cheeooo” ending, and not so firm and harsh. One of the Blackcaps, in the thorn-scrub area, had a fine mimetic song. Out on Horse Hill, the first two Swallows of the year flitted overhead, a solitary Kestrel beat its way against the wind, and half a dozen Jackdaws played and chased in the air, for all the world like a gang of naughty schoolboys.

Conservation, Natural History, Nature Reserves

Vole Patrol 10: Gutteridge Wood Voles!

Huma happy with first Field Vole in hand
Huma happy with first Field Vole in hand

Yes, luck was with the Vole Patrol today. We caught two species of Vole as well as the inevitable Woodmice.

The Field Vole is, as you can see, grey-brown above, and is softly countershaded  a la Abbott Thayer (who thought all animals were camouflaged in this way, even flamingoes, but I digress) from top to bottom with no sudden dividing line between dark and light. It’s diurnal and (therefore) has small eyes. And it has a notably short tail, 30% of its head/body length.

Huma very happy after Field Vole
Huma very happy after Field Vole

Huma, despite days with almost no sleep, looked and sounded delighted we’d caught this species.

We had turned up in the still-sleeping suburb of Hillingdon before 6am. The journey in was strangely easy on the empty roads, a fox running across in front of me in Acton with a jaunty air.

Vole Patrol arriving Gutteridge Wood 6am
Vole Patrol arriving Gutteridge Wood 6am

 

 

It was at once obvious on arriving that Gutteridge Wood, made a nature reserve by the Greater London Council in its closing days, was something different — an ancient woodland with fine Oaks as “standards” in between coppice stools of Hazel (cut on a regular cycle, so many shoots come up as useful poles from each stump), with Yew and Holly here and there, and English Bluebells and Woodrush as ground cover.

Gutteridge Wood Bank Vole
Gutteridge Wood Bank Vole

The team found a Bank Vole in one of the Meadow traps. It is a nocturnal mammal, unlike the Field Vole, and accordingly has big eyes (for seeing in the dark). It has a longer tail, 50% of its head/body length (try measuring it!), is appreciably redder than the Field Vole, and is more sharply white below.

While people were out picking up traps in the wood, a Woodcock flew right overhead, just above the bare treetops. Its enormously long beak and plump gamebird body were unmistakable, which was just as well because I haven’t seen one flying for many years now: a fine sight. Greater Spotted Woodpeckers drummed loudly; a Green Woodpecker gave its cheerful loud call. I guess you could easily guess what habitat I was in just from the names of those three species!

Gutteridge Wood Huma picking up trap by pond
Huma picking up a trap by the pond

The meadow and pond area was once a sewage works; if you peer closely at the pond in the photograph here, you’ll see behind the Reed Mace a circular brick structure left over from those days. It looks very much part of the waterscape today.

The Vole Patrol puts traps beside water, as here, along meadow edges (as above, for the voles), in a grid in the woods, and a few feet off the ground in the trees, to sample the small mammals in the different habitats on each reserve. Unsurprisingly, but very pleasingly, the ancient woodland of Gutteridge has given us good numbers of Woodmice, Shrews and Voles. It will be a pleasure to come back and listen to the Warblers in April or May, and to enjoy the Bluebell woods in the sunshine.

Vole Patrol 9: Perivale Wood (Selborne Society)

Natural History, Nature Reserves

Spring in the Air! Volunteering and Prototyping at Gunnersbury Triangle

First Comma of the year!
First Comma of the year!

Well, it only takes one still, warm sunny day and suddenly it’s SPRING! Sure enough, the frogs had gone crazy down the mangrove swamp, there was a great heap of spawn in the shallow water, and some excited children (and mothers). A pair of Comma butterflies wheeled and scurried about the sky in a long, intense dogfight, their whirling wings making it clear these were rival males of an orange species, if nothing else!

Hairy-Footed Flower Bee (Anthophora plumipes) male
Hairy-Footed Flower Bee (Anthophora plumipes) male

Mike expertly identified the Hairy-Footed Flower Bees around the Alkanets: they came out to warm up in the sun in some numbers. They have never been recorded before here, though we have surely had plenty of them, unrecognized.

Frogspawn in Mangrove Swamp
Frogspawn in Mangrove Swamp
Spring! Broom in bloom
Spring! Broom in bloom

The brilliant yellow of the Broom, and the foamy white of the Blackthorn flowers, announced that spring had sprung in a Botanical way, too.

Blackthorn in Bloom
Blackthorn in Bloom
The completed Hedgehog House prototype
The completed Hedgehog House prototype

The team spent the afternoon designing and making a prototype Hedgehog house out of Correx sheets left over from the Vole Patrol. We worked out a way to make a house from just two sheets, 54 x 120 cm each: basically one big tube folded 4 times to give 4 sides and an overlap flap, and two half as wide, one for the entrance tube, one for the two ends (joined along the ceiling with flaps on each end of the floor). We fixed it together with just 5 cable ties ingeniously stitched through bradawl holes. A challenge was to get the last stitch in, as the box was then fully closed! The trick was to take out the entrance tube and put a hand inside: the cable tie had to be poked out through a hole that of course we could only see from the outside! The result looks enormous and luxurious, so being Londoners of course we made a lot of jokes about Hammersmith Hedgehog Penthouses and luxury granite kitchens, etc etc. Anyway, we hope the hedgehogs will like them.

Natural History

Vole Patrol 9: Perivale Wood

Vole Patrol, Perivale Wood, dawn
Vole Patrol, Perivale Wood, dawn

The first cycle of trapping at Gunnersbury Triangle has been completed, and the action has moved on to Perivale Wood. This beautiful reserve is owned by the Selborne Society, the oldest nature conservation society in the world, founded in 1885 and thus a few years older than the RSPB.

Despite its name, Perivale Wood includes pasture (for horses), damp scrub, secondary wood on disturbed land, some hedges (we saw one newly “laid”, the trunks almost cut through and fastened at an angle with beautifully-woven withies), three ponds and two streams.

This, of course, enables London Wildlife Trust‘s Vole Patrol, by agreement with the Selborne Society, to search for small mammals in woodland, by water, and in meadow.

Walking in, we heard a Song Thrush, and much calling and drumming of Greater Spotted Woodpecker and Green Woodpecker. From the bare Oak trees of the photo above, I briefly heard an early burst of song from a Chiffchaff, my first of the year.

Lindsey scribing the data
Lindsey scribing the data

We met some new Vole Patrollers, including Lindsey, seen here acting as “scribe” for the all-important data, and Nicola, seen here weighing a Wood Mouse.

Nicola weighing a woodmouse
Nicola weighing a Wood Mouse

The team quickly sorted itself out, everyone sharing the necessary roles – fetching traps, opening them, weighing, measuring, sexing and coding the mice, recording the data, returning the mice to their exact locations, baiting the traps, and returning them to their locations. It’s not really complicated, but there is enough to do, and with over 30 traps in the different habitats around the reserve, each task has to be done many times.

Vole Patrol in Perivale Wood
Vole Patrol in Perivale Wood. In the distance, team members are fetching traps. In the centre, a trap is being opened inside the large bag,for the catch to be weighed and measured. In the foreground, a mammal is being coded before release. And behind the camera, a team member is recording events!