Stag Beetle at Gunnersbury Triangle

27 May 2016 Ian Alexander

Stag Beetle, just landed, wings not fully folded — Stag Beetle, Lucanus cervus, just landed, wings not fully folded

I was just walking around the triangle, talking to one of the Garden Design students about its natural history, when a mouse-sized animal scurried across the top of a post that we had hammered in to form a dead-hedge above the boundary stones. In my binoculars, it was at once clear what it was, a Stag Beetle. As I pulled out my camera, it spread its wings impressively, and flew a few feet across to the woven top of the dead-hedge, folding its wings but leaving the ends still sticking out of its wing-cases for a while.

So, all that work on loggeries may have paid off. Or perhaps it didn’t: behind the dead-hedge was simply a pile of brash and logs, abandoned for several years. Anyway, we’re very pleased to see a handsome adult male out in the sunshine.

The triangle’s first batch of Azure Damselflies, surely within a day of hatching, perched on leaves of emergent water-plants, or flew around in cop, laying eggs already. One or two Large Red Damselflies sunned themselves also.

P.S. A week later, on 4 June, a Lesser Stag Beetle crawled across the lawn in my garden. I guess it emerged from the dead wood stacked in odd corners for that very purpose. It’s a lot smaller than the Stag.

I picked it up to ensure I got a photo, and was rewarded with a fine display of thanatosis, shamming dead.

Natural History, Nature Reserves

Vole Patrol reprise: visiting nest boxes

26 May 2016 Ian Alexander

Huma and John on Vole Patrol with Mammal Nest Box Perivale Wood — Huma and John on Vole Patrol with Mammal Nest Box in Perivale Wood

We revisited the nest tubes and nest boxes that we put up for small mammals in four of the Vole Patrol study woods a few months ago. It seems another world: bare leafless trees over chilly wet forest floor have been replaced by a thick green mantle over a mass of brambles that seem to have shot up faster than tropical bamboos and bananas (my father maintained that he could watch a banana leaf unfurling while he shaved in the hospital he was running in postwar Malaya, but I digress).

So it was a case of first case your hare, or rather, first find your small mammal box. Gunnersbury Triangle’s densest parts are pretty thick, and the nest tubes had been put up somewhat at random as the new team did its enthusiastic best on its first day of training all those months ago, followed by the brambles doing their enthusiastic best to hide all traces. We did well to locate 14 of 18 nest tubes: none of them seemed to have been used. We moved on to Perivale Wood, where stout wooden boxes like bird nestboxes had been tied to trees in a much more regular array, and we found them without too much difficulty.

Mammal nest box used by Wood Mice, with opened hazelnuts

Three of the Perivale boxes were inhabited by Blue Tits, the helpless youngsters lying inside while (we suddenly realized) the alarmed but brave parents chattered excitedly outside. We closed the lids and backed off as quickly as we could. The boxes have the openings on the back to encourage mammals and discourage birds, but it’s of only limited value against sharp-sighted Blue Tits. One of the boxes had certainly been used by mammals: two hazelnuts had been opened by small teeth, their ends neatly gnawed to circular holes. I’m not certain I understand how a nut can be withdrawn through such a little hole.

Off to Tentelow wood through the grinding traffic. A game of cricket was going on in the playing fields; it was hot in the sun, a lot cooler under the canopy. The nettles were waist high, the brambles thick. It seemed impossible we would find any of the nest tubes, but we did, eventually. A Scorpion Fly perched on a bramble leaf beside the path.

Sir Thomas Gresham's symbol, a golden grasshopper (a pun on his name, Grass-Ham), at his building in Lombard Street — Sir Thomas Gresham’s symbol, a golden grasshopper (a pun on his name, Grass-Ham), at his building in Lombard Street (photo: Wikimedia Commons)

Then we drove down to Long Wood, part of Sir Thomas Gresham‘s Osterley Park estate. He liked insects enough to use a golden grasshopper as his symbol, punning on his name, which might be Grass-Ham, village in the grass. It’s a beautiful wood, coppice with fine tall straight Oak standards, a proper stream running clean through a steep-sided valley, sullied only by the continuous roar of the M4 invisible above. Chiffchaffs and Blackcaps sang above the din.

Brown Silver-line Moth Petrophora chlorosata at Long Wood, Osterley

I disturbed a Brown Silver-line Moth, which flitted among the nettles and bracken. We saw Holly Blue, Speckled Wood, Large White, and Red Admiral butterflies: it looks a fine place for Purple Hairstreak too.

When I got home, I found this funky weevil under my shirt. It looks very much like the Acorn Weevil, presumably from one of the many Oaks I walked under.

Natural History

Click Beetle, Shield Bug at Gunnersbury Triangle

17 May 2016 Ian Alexander

lick Beetle on goose-grass — Click Beetle, Athous haemorrhoidalis, on goose grass

Coreus marginatus shield bug, distinctive horns between antennae

As well as the handsome insects, a migrating Tree Pipit called from the wood near the Picnic Meadow. These once common birds are now scarce on farmland and have disappeared from London as breeding birds, but still drop in occasionally in spring and autumn migrations, and breed on larger commons such as at Thursley.

Natural History

Mayfly, Damselfly hatch; 5 Warblers!

14 May 2016 Ian Alexander

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.

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!

6 May 2016 Ian Alexander

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, 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.

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

5 May 2016 Ian Alexander

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.

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.

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 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.

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.

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

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.

ObsessedByNature

Monthly Archives: May 2016

Stag Beetle at Gunnersbury Triangle

Vole Patrol reprise: visiting nest boxes

Click Beetle, Shield Bug at Gunnersbury Triangle

Mayfly, Damselfly hatch; 5 Warblers!

Garden Warblers All Over Watlington Hill!

Hoverfly Diversity at Gunnersbury Triangle

The English seem unemotional … except for their passion for nature