Blue Butterfly (Adonis Blue - Polyommatus bellargus

    Nature notes: what to look out for this summer

    16 July 2019

    The earth has turned and we are now on a new trajectory; the days are getting shorter, but for a while, nature is largely in relaxed mode during this season of plenty and slack around the solar “high tide”. Most of our birds have finished raising their first brood. Only the other day I saw a very scruffy diminutive bird chirping from our windowsill; so the chaffinches in the honeysuckle must have fledged. Flocks of all sorts of newly-flown adolescents can be seen fluttering down rather clumsily from trees to seedy flowers beneath. They are inevitably garrulous as they have not yet given up their noisy nursery clamour for food.

     There are a few exceptions. The barn owl is still busy with her brood. If you catch sight of her – or him – you are in for a treat. They hunt utterly silently and tend to glide at around head height above long grass verges and hedgerows, looking, or rather listening, for shrews, mice and other small mammals. Combined with their eery screech, their ghostly white feathers undoubtedly earned them their more gothic reputation, like Lady Macbeth’s “fatal bellman”. They are all about their ears: these are placed asymmetrically on their head so they can triangulate where the sound is coming from; even their facial plumage is designed to funnel the sound to their ears; and their feathers are unoiled and much softer than other species’ so that the wind is gently and therefore silently dispersed over them in flight. Wet or windy weather literally foils their hunt, so to survive a bad season, their survival tactic is to do a staggered incubation; that way there will always be a stronger and older chick, which, if starving, can eat its younger siblings!

     The skylark, too, is late to fledge. Being a ground nester, their breeding success is woefully dependent on the timing of the harvest; the later the better, which means delaying the hay cut into late July or into August. Unlike the barn owl, they are not known for their silence. We are lucky enough to have some around us here; probably 4 or 5 males, which means that the sound of their exuberant, gushing song is almost never stilled. Somehow they manage to take off diagonally at first and then ascend vertically, sometimes out of eye sight, singing heartily all the while. Their song never fails to lift your spirits and has to be one of our most-loved native sounds, inspiring poets and musicians alike. While we associate it with summer, in fact, the males start showing off as early as February, and so they have become one of my top sources of winter cheer. Seeing them is less exciting; they are little bigger than a sparrow; pale with brown streaks to camouflage them in pasture! But, it is quite amusing to see them descend in large intervals, as they run out of puff and finally drop to the ground without further ado. But they have the last laugh; they drop down intentionally some distance from their nest, so that they don’t give its location away to predators.

    Common Skylark

    The hedgerows and verges are also reaching their fullest and most verdant season. The fresh young green growth matures to deeper shades, but the flowers still keep coming. Red valerian and rosebay willow herb are two imports that have happily self-seeded themselves in the slip stream of passing cars, and presumably in the hooves of cattle before them. The former is thought to have been brought over by Tudor sailors from the Mediterranean (it has a spectacularly long flowering season, and locally enjoys self seeding in our Cotswold dry stone walls) and the latter is imported from North America. Hogweed, the more brutish cousin of cow parsley, now holds sway, which along with ox eye daisies, keep the white sources of nectar going for the insect population. Poppies and thistles add more glamorous splashes of colour, while sometimes, from a distance, the poppies join-up to colour the entire field. (Poppy seeds lay inert in the soil and need only to be disturbed to trigger their development).

     We are still learning about the delicate relationships between flora and fauna. For instance, the much maligned common ragwort (hated by horse lovers on account of its toxicity) is the sole food of the beautiful cinnabar moth caterpillar. Cleverly, the caterpillar absorbs the hydrogen cyanide and the moth becomes toxic to its predators; hence the danger warning in its bright red markings, (known as “aposematism”). Leave the ragwort and encourage these gorgeous moths! After all, who in their right mind goes round pulling up daffodils or foxgloves, just because they too are poisonous? And talking of moths and butterflies, now is definitely the time to start getting acquainted with some of our most attractive species. This is the time when the grasses are in full flower and other late flowers in the sward: like buttercup, clover, trefoil, vetch and sorrel, are finally doing their thing.

    Polyommatus bellargus, Adonis Blue butterfly on field

    This is the high season of the wild flower meadow. I am having difficulty telling the difference between my Adonis Blue or Common Blue; as they never stay still long enough for me to see the finer points of their minuscule white margin or the delicate hue of their underside! But, I can tell you that if you see a kaleidoscope of brown / orange butterflies with a twin eye spot on each wing, feeding on bramble flowers, they are almost certainly Gatekeepers, taken by many naturalists to be a sign that summer is at its height. And have you noticed how large the bramble flowers are this year? We have noticed the same thing with our strawberries, too, and we would love to know why that is….

     Answers on a postcard, please!