Creatures of the night do battle in the dark woods

Times

3 days ago

The natural world at night is a world at war. Walking through the night-time wood after checking the sheep, I slapped at mosquitoes and other biting insects, and recalled why I am word perfect on Vivian's library scene lament in Oscar Wilde's The Decay of Lying: 'Enjoy Nature! I am glad to say that I have entirely lost that faculty… Nature is so uncomfortable. Grass is hard and lumpy and damp, and full of dreadful black insects.'
People who gush endlessly that nature is wonderful are people that do not spend enough time in nature. And in the primitiveness of the night, nature's discomforts and bloodiness seem particularly acute. If fascinating.
As I hurried along, flapping my arms fit to fly, I caught sight in the moonlight of a swirl of long-eared bats (Plecotus auritus) in the pine glade. They were corralling a shoal of white moths into the centre of the glade, where the Lepidoptera made easy pickings. This is the second time that I have seen this batty herding phenomenon.
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The long-eared bat, like others of its Chiroptera ilk, is locked in a millennia-old co-evolutionary arms race with its moth prey, with each species developing counter-measures to maintain survival. In an upping of their armoury, long-eared bats now use the sense of smell to help hunt moths. Meanwhile, some hawk-moths have evolved to hear with their mouthparts and respond to bat calls with evasive manoeuvres.
Tiger moths (Bertholdia trigona) can use their own ultrasound clicks to jam the echolocation signals of the big brown bat (Eptesicus fuscus). So, I am left wondering whether the apparently co-operative hunting of the long-eared bats is a fluke, or an escalation in the arms race.
As local names such as 'muckweed', 'dirty jack' or 'dirtweed' indicate, fat-hen (Chenopodium album) is a plant of the farmyard and well-manured field. For the Anglo-Saxons it was 'melde' and its historical abundancy gave it a place in national toponomy, with Milden in Suffolk and Melbourn in Cambridgeshire.
Like peoples before them, the Anglo-Saxons used fat-hen as a food for humans and fowl, hence the 'hen'. As well as being harvested for its seeds, fat-hen was eaten as a vegetable until spinach and cabbage knocked it off the plate in the 16th century.
We classify fat-hen today as a weed or wildflower, yet for millennia it was cultivated as well as gathered: the wild and the farmed were not discrete in the old times. Indeed, my grandfather, as late as the 1960s, expected the farm to 'crop' wild things (from blackberries to hares) as well as the planted and the tended.
They knew a thing or two, those ancients: in this year of drought my farmed crops have struggled, but we have on the manure heap a quite excellent accidental crop of fat hen. In August, the spire-shaped fat hen is at its peak height, a metre and a half, and the profuse green flowers are already turning to seed.
The grey-green oval leaves are often conspicuously covered in a white, powdery meal ('album' in the plant's scientific name refers to this white dust, which is strictly speaking an epicuticular wax). As well as fattening humans and poultry, the seeds are beloved by hungry buntings and finches in winter.
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We have a sky full of swallows. The juveniles from our three nests — and I am aware of the unsuitability of using the possessive pronoun for wild things — have joined their novice fellows up in the blue. There are, as I write, perhaps 50 young Hirundo rustica skirling above the house and surrounding fields; their constant communication with each other a joyous baby babble.
Our largesse in swallows is not accidental; we and our neighbours keep livestock — hence the manure heap — and where there is outdoor livestock run on nature-friendly principles there are swallows. It could hardly be other.
In his pioneering study 'The Larval Inhabitants of Cow Pats', Journal of Animal Ecology, 23, 1954, BR Lawrence calculated that the dung of a single outdoor cow supported nearly 2.2 million insects a year. Which is quite a lot of grub for swallows.
Folklorically, swallows are weather indicators, thus the saying, 'Swallows high, staying dry; Swallows low, wet will blow.' On fine days warm air rises upwards, carrying the gauzy-winged insects with it. Consequently, the insectivorous swallows fly high to find their food.
Conversely, during unsettled weather the insecty things seek the shelter of trees and vegetation, requiring swallows to swoop low — sometimes just millimetres off the ground — to catch them.
John Lewis-Stempel is the author of England, A Natural History