Another Life: When birds go into hiding and butterflies disappear

We miss the mistle thrush. When the fine evenings began he would fly to the topmost tuft of the scrawny old spruce at the gate and point his beak steadily due west, as if transfixed. Even a stormcock can like to watch the sun go down, but perhaps the novelty has worn off.

We also wonder at odd absences in the life of the little willow warbler, whose extravagant energy has had us mesmerised at the kitchen window, watching it skimming grasses, flowers and weeds to rummage ceaselessly for spiders and hovering to snatch flies.

When the dazzle of goldfinches disappeared from the nut feeders, leaving these to the house sparrows, we hoped that two of the dozen were “ours”, as it were, and would stay on to breed. The cock that sang from the elder, with that charmingly toy-like, swivelling stance, seemed duly promising but eventually fell silent. Now the whole family has emerged from wherever, whirring brightly together along the hedge like a troupe of Moroccan tumblers, the fledglings begging to be fed.

The swallows, meanwhile, finding a way into the closed cave of the car shed, have made an entirely new nest above the bonnet, its consequent decoration with splashes of white guano and parental baby wipes a trial of our goodwill.

So the birds come and go to their own calendars and schedules. I need to watch my step on the garden path for earth-coloured baby robins and lone teenage blackbirds in their first long feathers. When the young are reared, in another month or so, their parents will start hiding, to finish changing their own plumage.

Big birds like barnacle geese drop all their flight feathers at once in the postnuptial moult; in Greenland these litter the edges of lakes, and the flightless birds paddle safely to the middle if an Arctic fox appears. But the perching birds of the Irish garden, exhausted from breeding and gathering food, still need to be able for instant flight. They push out the old, worn primaries of wings and tail in single pairs at a time, one feather from each side to preserve their aerial balance.

Bright colours

Some moults quite disguise the bright feather colours of spring. The male mallard duck, having dropped its flight feathers like geese and swans, moult into others as drably brown as the female’s – an “eclipse” that lasts for weeks.

The starling starts changing its feathers about now, to new ones with pale tips that give the bird its dull winter look. By next spring these tips will have worn away, leaving the starling sleek and iridescent for the mating game. The gathering flocks of juveniles, too, have their transformation ahead and puzzle people with their dusky plainness. Tits, finches and buntings also use the abrasion of discreet and protective winter plumage to restore the bright colours they have in the bird books.

The silence and shyness of most garden birds as summer wears on and the general dispersal of the young ones can bring anxious letters to Eye on Nature. But “Where have all the birds gone?” can be a question even for the spring, sometimes in the belief that magpies have eaten them. (Only 10 per cent of their diet, at most, involves birds.) Severe winters, chilly springs, changes in vegetation or sources of food – even changes of the avian mind in deciding where to nest – have their effects.

Range of species

Just now it’s not birds but butterflies I’m short of – and this long after the start of a proper summer sun. Since the trees and hedges grew tall on the acre the range of butterfly species we attract has diminished. Even a single peacock or small tortoieshell becomes an event – despite the liberal clumps of nettles for their eggs. The one butterfly our shade and wild grasses have favoured, often flying in abundance from April to September, is the brown and busy speckled wood. But cocksfoot grass, a favourite food plant for its eggs and caterpillars, has so far waved in vain.

The importance of habitat and food plant in knowing which butterfly to watch for where is splendidly shown in The Butterflies of Donegal, by Bob Aldwell and Frank Smyth (€12.50, Ashfield Press). The book, by two lifelong lovers of the county, is based mainly on a survey of its butterflies between 1998 and 2014. This involved 160 voluntary recorders and landowners; the thoroughness is reflected in a score of recommended sites, each with its photograph and species.

Donegal’s great diversity of landscape, from the warm and flowery microhabitats of the sandy coastline to the windy bogs and uplands of the interior, supports a remarkably full range of Ireland’s resident butterflies. This book will offer a baseline for the northward expansion of species as climate change takes hold.