Profitable Wonders
Serious seabirding is not for the faint-hearted.
‘Only those who have lived in a tent continually battered by northerly gales can comprehend the wearing effect on nerves and temper,’ wrote Frank Fraser Darling of almost a year spent on the desolate rock of Priest Island, off the coast of Wester Ross.
Still, his privations were well rewarded. He witnessed, at close quarters, the complex social lives of gulls, fulmars, guillemots, gannets, razorbills and numerous other species.
His Bird Flocks and the Breeding Cycle, published in 1938, is full of original observations, most notably about the formalised dance routines of communal courtship – particularly that of the heavy-beaked razorbill, resembling a Highland Reel.
‘They gathered on the sea in single file and then formed a circle, their raised beaks almost touching in the centre,’ he wrote.
The circle widened and broke up. A couple paired off, bobbed and came together, waltzing around, holding each other’s beak ‘in a posture of rapturous ecstasy’. This continued for a quarter of an hour, culminating in a finale of excited wing-flapping. ‘Finally they all rose from the water together and flew seawards, just topping the waves.’
Meanwhile, several hundred miles to the south, another self-taught naturalist, Ronald Lockley, on the island of Skokholm off the Pembrokeshire coast, would spend several years working out by degrees the little-known life history of the Manx shearwater.
These dark, stiff-winged ocean voyagers arrive in their thousands to breed in early February. They make their nests in burrows – often a disused rabbit hole – where the female lays a single egg.
Though concealed underground, Lockley was able to keep track of one pair’s daily routine by the simple expedient of cutting out a replaceable clod of earth directly above their nest.
This ready access provided the further opportunity to conduct his pioneering ‘displacement experiments’. These started in a small way. He relocated one of a pair to Devon, leaving her partner to tend their egg, and monitored how long she took to return.
Subsequent displacement excursions followed to ever more distant locations, culminating in an epic trip by plane to Venice. Having released her from the island of Giudecca on 9th July, Lockley found her reunited with her partner and (now hatched) chick two weeks later.
‘I stroked her in the moonlight with awe,’ he told a meeting at London’s Royal Institution in 1939 – though he could only speculate as to the route she might have taken.
Still, for all the fascinating findings gleaned from these and more recent studies, much about seabirds’ lives remained obscure – until the discovery, just over 20 years ago, of ‘the long sought-after key to a vista of wondrous new knowledge’.
That ‘key’ is a miniaturised packet of electronics, weighing less than a broad bean, which records – or relays back to satellites – streams of data, whose ‘wondrous’ insights are described by ornithologist Michael Brooke in his recent book Far from Land.
The journey home from Venice of Ronald Lockley’s shearwater is a mere stroll in the park compared with the ocean mastery of 12 of her fellows – as revealed by the geolocators attached to their legs.
Flying direct down the west coast of Europe and Africa, crossing the Equator they picked up the trade winds that carried them across the Atlantic to Brazil and on to the rich fishing grounds of Patagonia – 5,000 miles in under a week.
Then, a few months later, they flew back, again exploiting the trade winds but in the reverse direction – up through the Caribbean to the eastern seaboard, before heading across the North Atlantic back to Skokholm.
The skills required for this and other similarly spectacular trans-oceanic migrations are, we are informed, learned, not innate.
Next, seabirds are paragons of fidelity until parted by death. So how astonishing to learn that Sabine’s gulls, for example, having nested together in the Canadian Arctic, should elect to separate for the winter months. He heads for South Africa, while she ends up off the coast of Peru – only to be reunited in the Arctic, arriving within a few days of each other.
That fidelity is manifest too in their taking it in turns to forage for their young. Here again, those geolocators have revealed an unimagined flexibility whereby, for example, kittiwakes time their lengthy fishing expeditions to coincide with the daily tidal cycle when food is most abundant.
Those miniaturised electronics are now so refined as to detail how seabirds feed and what for. The cormorant routinely dives 50 yards below the surface of the water in pursuit of its next meal. The albatross consumes two stone of its preferred food, the squid, every week.
And there are, of course, many, many more of these extraordinary seabird stories.