Another Life: A flight course around the planet’s shifting extremes

Michael Viney: The flycatcher has earned its reputation as one of nature’s ‘amazing’ birds


One of the bird world's "amazing stories", as offered by the British Trust for Ornithology (BTO), was the recovery of a spotted flycatcher in the mountain woodland of Angola in Africa in January 1988. The bird had been ringed as a chick in Cashel, Co Tipperary, in June 1984 with the number B982864.

Thus, at four years old, as the BTO points out, this sparrow-sized migrant could have flown 49,000km in its lifetime, which is further than flying right round the Earth.

This came to mind a week or two ago when a spotted flycatcher perched repeatedly on a twig of firethorn directly outside my bedroom window. A second or two’s rest and it was arrowing across a neck of lawn to perch on another twig about 10 metres away.

Then it arrowed back to my window, for one of many identical return flights – all, so far as I could see, without so much as a passing swerve for a midge. Indeed, opening the bedroom curtains at 6am next morning (I, too, am an early bird), I found the flycatcher on its twig, poised for the next routine and seemingly-preyless trajectory across the lawn.

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It had first appeared last summer, much to my delight – a quite new migrant to our tangle of trees. And its chosen perch, at first sighting, was the same branch across the lawn, from which its repeated sorties to snap up distant flying insects had held me fascinated.

Discovering a good place to nest and feed their young, the flycatchers, like other long-distance migrants such as swallows, tend to stick to it. But having failed to trace a nest in the acre’s tangle of leaves or see any obvious offspring, I am left to guess at what guided Muscicapa striata to our isolated copse on the hillside.

Decline

The flycatcher's fortunes in these islands has been patchy, with massive losses in the south of the UK. By some estimates, there were eight times as many of the birds in Britain and Ireland before 1970 as there are today. The decline in the UK is blamed partly on avian predators of the chicks, notably jays.

In Northern Ireland , the bird is a “priority species”, commonest in the wooded Glens of Antrim, but BirdWatch Ireland seems content to find it still “widespread”, breeding in broadleaf woodland and sometimes using nestboxes. A BTO study finds Ireland with some patches of high density, and western Ireland showing “new areas of colonisation” – which could be us at Thallabawn.

This may be more than you want to know about little Muscicapa striata, brown on top, pale underneath, a bit streaky when young, but the bird’s big decline in the UK has made it “a poster bird for the cause of African migrants” in the eyes of the BTO.

This organisation runs the whole programme of licensed bird-ringing in Britain and Ireland. It has also been studying migrations of the cuckoo, their numbers down by half in the UK. Ultra-lightweight satellite tags have been tracking their routes to and from the forests of the Congo.

The BTO admits that its knowledge of the ecology of migrants on their African wintering grounds is still extremely poor and hampers explanations of decline. The finding of the ringed Irish flycatcher, dead in an Angolan forest (and now preserved in a museum there), was a rare addition to knowledge.

Long distance

For me, this summer’s close encounter with the bird has triggered basic questions about long-distance bird migration. I accept that birds began to move with the seasons, travelling from areas with dwindling food supply to summer in good, leafy nesting places with plenty of flying insects, then back again as the seasons turned, with reproduction done.

But whirring its little wings for 7,551km each way and losing half its body weight on the flights? How did the flycatcher come to stretch that far?

Well, I’m told, it was the series of ice ages, their advance and retreats moving Earth’s leafy boundaries back and forth. Breeding zones moved north to follow the retreat of the glaciers, offering reliable food and longer days in which to find it, then winter compelled return to the tropics. As millennia passed, to Earth’s glacial pace, the ever-longer journeys became coded in the genes.

Today’s migrants travel a planet shifting to fresh extremes of drought and desert, floods, wind and fire. The BTO is studying the drought-busting rains of a weather frontal system that may cue the Congo cuckoos to start flying north.

My flycatcher, meanwhile, is nowhere to be seen, perhaps discouraged by the absence of nourishing wasps and bees. Will he return late next spring, perhaps paired, to the branch he’s made his own? I look forward to being surprised all over again, at the same leafy spot on the dial.