FIVE
Fishing for a Living
The waters of the earth, either salt or fresh, not only cover most of its surface but in some parts are even richer in food than any equivalent area on land. Not surprisingly, therefore, some of the animals that evolved on land have turned to the waters for their food. A few reptiles have done so – crocodiles and turtles. So have a few mammals – otters, seals and whales. But no group of land-living animals have done so in such numbers and in such variety as the birds.
Birds need few physical modifications to enable them to snatch morsels from the shallow edges of the water. That most brilliant of all British species, the incomparable little turquoise-blue kingfisher, sits on its regular perch above an English stream, short of tail but armed with the long dagger of a beak. At the sight of a small fish in the water below, it will flash into action. If its perch is a low one, only a few feet above the surface of the water, it will fly upwards to gain height to give itself room to gain speed on its dive. Then down it comes, increasing its momentum with a few flickering wing beats. With wings extended but folded back tightly against its body, it plunges into the river. Its target may be a minnow or a stickleback. Even if it is as much as a metre below the surface, the kingfisher will be able to reach it and seize it with its beak. Beating its wings below water to help it rise, the little bird shoots up through the surface and flies off to a perch. There it kills its victim by thrashing its head against some hard object and, with one gulp, swallows it. The whole act is a display of extraordinary skill, performed without hesitation or fumble, and can be completed in a few seconds.
The African pygmy kingfisher, in size and coloration, is remarkably like the European species. Watch it feeding and you will see a very similar performance. But there is one crucial difference. This bird lives not on a riverbank but in the rainforest, and it catches not small fish but insects. In fact, this is more typical of kingfishers as a group, for some two-thirds of the family live away from water. In Australia, they grow large and take land-living prey of some considerable size – the kookaburra captures lizards and snakes. So the kingfisher’s superbly controlled accurate dive seems to have been developed originally to pluck prey from the ground. The birds that pioneered diving for fish had to learn how to offset their aim to allow for the way that light bends as it enters or leaves water; and some developed the muscular skills needed to hang poised in the air while taking that aim. They achieved this without the radical skeletal modifications evolved by the hummingbird. Their hovering skills are not, it must be said, as great for they cannot maintain a position in mid-air with the perfect steadiness of a hummingbird. Most need the assistance of a little wind in order to hang on trembling outstretched wings. But one of them, the pied kingfisher, is able to hover even in still air. And that brings it a major advantage over other kingfishers, for it is no longer tied to a perch but can take up a stance wherever the fishing seems most promising.
Other birds walk around the water’s edge looking for their prey. The wrybill, a small plover, searches among the pebbles of New Zealand rivers. Uniquely, it has a beak which is bent sideways – and always, for some reason, to the right. By cocking its head to the left, the bird can slip this remarkable asymmetric instrument beneath a heavy pebble, open its mandibles and scrape off fish eggs, insect larvae or anything else edible that might be clinging there. One wonders why it, alone among the birds of the world, should have developed such a curious technique. Maybe the reason is connected with the fact that, until recently, New Zealand had no land predators. Danger, for the wrybill, can only come from the air, in the shape of a hawk. Feeding with its head bent not downwards but to one side enables its left eye to keep scanning the sky for trouble.
Herons also fish along the margins of the water, moving with extreme stealth, freezing into total immobility the moment a slight flash in the water gives a hint of a meal. The little black heron of Africa and Madagascar shades its eyes while searching. As it stands with water halfway up its legs glaring intently at the surface, it brings its wings forward to form an umbrella over its head. And there it crouches, for minutes at a time. Sometimes, without changing the position of its wings, it sticks its head up from between them and looks around, just to see what is going on elsewhere, and then draws it back in again to resume its watch on the water. The obvious explanation for this performance is that it is shading its eyes from the glare of the sun just as we do with our hands. Maybe it is simply cutting out reflections from the surface of the water. Maybe the explanation has nothing to do with optics and more to do with the behaviour of fish. They often seek a shaded part of a stream where they are less visible to fishermen. Maybe the heron, by creating a pool of shade, is persuading them to swim within range.
Herons are certainly ingenious and inventive fishermen. In Japan, striated herons attract their prey with bait. A few years ago, some were living beside a lake in a public park where people come to feed ornamental fish. One particularly observant or inventive heron watched them and started doing the same thing. It picked up a piece of bread or some other edible fragment that it did not eat but fish did, took it down to the edge of the lake and flicked it on to the surface of the water. A fish came up to take it – and was itself taken by the heron. The habit spread. Then the technique became more sophisticated. Human fishermen have long known that fish are inquisitive. An object need not necessarily be edible to attract them. A bright piece of metal spinning in the wake of a boat will trigger a snapping reaction. So will a small, brightly coloured piece of fluff. Birds too, have been exploiting this tendency for a very long time. The little egret, which has black legs but bright yellow feet, will stand on one foot and shake the other in the surface of the water like a limp yellow glove, and attract fish that way. The striated heron in Japan, having had its success with pieces of bread, has recently started to use little feathers for the same purpose. And that too works.
Skimmers also benefit from the urge fish have to investigate the unusual. The skimmer has the oddest of beaks. Its lower mandible is almost twice as long as the upper. The birds, as big as gulls with black and white plumage, sit in flocks on sandbanks. In Africa, they live on rivers. In North America, the species seems to prefer coastal lagoons. But they only live beside waters that are still and regularly free from waves. When they decide to fish, they take off and then, flying so low over the surface of the water that their wing tips almost touch it, they open their beaks so that the elongated lower mandible cuts a furrow in the water. If that mandible touches something hard, it will snap upwards, closing the beak and catching whatever triggered it. With luck, this may be a fish rather than some solid floating object. Either way, the shock on the beak of the swiftly flying bird must be considerable, but the skimmer has particularly strong muscles in its head and neck which act as shock absorbers. They are seldom successful on this first traverse. But having reached the end of their stretch of river, they turn round and fly back over the course they have just covered. The ripples are still spreading and often by then have attracted fish up to the surface to investigate. So the skimmers’ second run is often more fruitful than the first.
Entering the water in order to find food clearly presents greater problems than making brief dips with the beak. Because birds are warm-blooded, they run the risk of getting seriously chilled. Swimming mammals, such as whales and seals, guard against this by developing swathes of fat around their bodies which insulates them very effectively. Birds, if they are still to fly, do not have the option of such a weighty expedient, but they have their own unique and very effective alternative – their plumage. The feathers that enable them to fly also trap air and keep them warm on land. They will do the same thing underwater, provided they are able to retain that air.
The European dipper relies on that. It is a small brown bird about the size of a thrush with a white bib that lives on the banks of swiftly flowing rivers and streams. It has a particularly large preen gland on its rump and takes special care of its feathers, anointing them with water-repelling oil. When it decides to feed, it walks down to the water and with no break in its pace disappears below the surface. In spite of the flow of the water, it is able to walk along the stream bed, turning over pebbles with its bill, probing beneath bigger ones, searching for the larvae of caddis flies and other insects. If it needs to swim, it does so with rapid beats of its short, rounded wings. To protect its eyes and to enable it to see underwater, it has the equivalent of a diver’s goggles, transparent membranes that it can draw across its eyes. And thanks to its well-oiled feathers, it shows no sign of chilling even though it may remain below the surface for up to ten seconds.
The disadvantage of using air as insulation is that it is buoyant. The dipper has to hold on tight with its toes to prevent itself from bobbing up to the surface. The anhinga, which lives in somewhat warmer parts of the world than the dipper, does not have that problem for it has dispensed with such insulation. It has no preen gland and its feathers actually absorb water, so when it enters a river it quickly becomes soaked to the skin. Its buoyancy is so low as a result that when it swims its body is almost submerged with only its long thin neck easily visible. This, swaying from side to side as the bird swims, looks rather like a snake and for this reason the anhinga is often called a ‘snake bird’. Such low buoyancy brings a special reward. The anhinga is able to walk along the stream bed and stalk fish with the stealth, sudden frozen postures and the swift attack that herons use out of water. It may even use an underwater version of the black heron’s trick of opening its wings to attract small fish to their shade. After a successful hunt, it emerges with the fish impaled on its dagger-like beak. With a vigorous shake of its head, it detaches the fish from its bill. Then it throws it into the air, catches it and swallows it head first. But drenched plumage, like a wet bathing costume, needs to be dried quickly if its wearer is not to get chilled. So when the anhinga emerges from fishing it hangs its feathers out to dry by sitting on its perch with its wings outstretched.
Snake birds and dippers, herons and kingfishers live beside water. Ducks live on it. Because they are so familiar, we tend to forget how remarkably specialised they have become to the aquatic life. They rest, feed, court and mate on its surface. To do all that, they need efficient paddles and their toes accordingly have become connected with webs of skin. Just as the most effective position for a ship’s propellers is at its stern, so a duck’s legs are placed far back on its body. As a result, while a duck is as admirably agile on the water, it is generally quite clumsy on land.
The pochard collect roots and bits of vegetation. Eiders collect molluscs. The tufted duck is omnivorous taking crustaceans, insects or seeds according to the season and the locality. The goosander and the smew not only eat shrimps and worms but are also very adept at catching fish which they chase actively underwater. Their bodies are more slim and streamlined than most other ducks and their mandibles are finely notched like saws, so that they are able to catch and hold small slippery fish.
Divers, or loons as they are called in North America, eat nothing but fish. Their webbed feet, placed at the very far end of their body, give them great speed underwater. With their wings clasped tightly against their body so that their streamlining is near perfect, they pursue their quarry and often manage to out-manoeuvre them in their own medium. The great northern diver regularly swims down to a depth of 20 metres and stays below the surface for as long as a minute or more. Out of water, however, it is as clumsy as it is agile in it. The bird can barely walk. It flops down on its breast and can only move forwards by holding its feet together and making short awkward hops.
Lakes are not, in the long run, permanent features of the landscape. The rivers that supply them with water also fill them with mud and sand. Over the decades, their waters shallow. Reeds growing around their margins are supplanted by bushes and small trees. Slowly, lakes turn into swamps. Then new kinds of fish and new kinds of fishing birds come to them.
In hotter parts of the world, the lakes may each year evaporate altogether. If that happens, the birds that feed in them will be able to fly elsewhere, but the fish are trapped. They must have ways of surviving the drought. The African lungfish, at the beginning of the dry season, takes the precaution of burrowing into the mud at the bottom, wrapping its tail around its head and secreting slime. If and when the swamp is baked dry, it will be able to survive in a state of suspended animation, obtaining all the oxygen it requires by absorbing it through a pair of finger-shaped projections from its gut. The shoebill stork prevents many of them getting to this stage. It is a truly formidable bird. Its powerful, massive beak is so big that the bird is also known, justifiably, as the whalebill. It stands 120 centimetres tall. As it wades slowly through water clogged with vegetation, it holds its huge bill vertically downwards so that it can focus both its eyes on the water. If it spots a lungfish lurking on the mud at the bottom or feels it with its feet, it lurches forward with its whole body and plunges its bill into the water. Using its wings as arms, it pushes itself upright again with a 30-centimetre-long lungfish wriggling in its great beak.
As the season progresses, the lakes continue to shallow. Fish that swam in comparative safety become increasingly vulnerable and birds travel from far and wide to claim a share in the banquet that is in prospect. Now those with long legs have conditions that best suit them. Striding through the muddy waters, yellow-billed storks, herons and egrets stab and thrust at their wriggling prey. It is not just fish that are there for the taking. There are frogs, snails and other freshwater molluscs. These are the favoured diet of the African openbill, one of the storks. It has a curved upper mandible so that its beak, when it is closed, has a gap in the middle. It does not, however, use that like a nut-cracker for breaking snail shells. Instead, it first pins down the snail with its upper mandible and then uses the sharp tip of the lower mandible like a knife to sever the muscle which attaches the snail’s body to its shell. Once that is done, the bird deftly extracts its meal, leaving the snail shell unbroken.
As the waters continue to shrink, so all the small creatures that once flourished in the deep water at the bottom of the lake come within reach of the flocks of birds searching the muddy shallows. Spoonbills filter out tiny fish and shrimps with sideways sweeps of their beaks. Often they work together, advancing in a line abreast so that if small creatures disturbed by the advancing feet escape one beak they are caught by the next alongside. They are even capable of swallowing quite large fish. Ibis probe deeper into the mud with their long downward-curved bills and plovers pick up the swarming insects.
Such conditions occur, not just once a year but twice every twenty-four hours along the margins of the world’s seas. Every time the tide retreats, the salty waters leave behind a spread of food that is so rich and so regularly renewed that a whole range of birds specialise in feeding here and nowhere else. In such a competitive community, there is no room for the generalist who is reasonably successful at collecting many different kinds of food. Here a species, if it is not to starve, has to be more swift and efficient at reaping a particular crop than any other around. So each kind of bird here has come to favour one kind of food and starts to collect it just as soon as it is made available by the retreating sea.
Dunlins and sanderlings frequent sandy beaches, pattering along the edge of the water. As each wave swills back, they follow it, probing and pecking at any morsel that it has stranded; and then as the next wavelet floods in, they run back again up the shore. On more pebbly beaches, it is turnstones that pace along the water’s edge, flicking over small stones with their short, wedge-shaped uptilted bills, picking off little shrimps and other crustaceans.
As the tide falls back still further, it may expose a flat of mud. Oystercatchers regard this as their territory. As the first edge of the mudflat is exposed, they squabble and shriek at one another, jostling to find a place to feed, but as the falling tide reveals more and more, so they are able to spread out and feed without impeding one another. There are two kinds of food to be gathered from the mud – worms and shelled molluscs. Some families of oystercatchers trot swiftly across the mud, stabbing at the head of a worm whenever they see one. They have to move fast if they are to catch a worm unawares before it has time to disappear down its burrow. Other oystercatcher families feed in a much slower way, stalking over the flats and probing deeply with their beaks to haul up a mussel or some other mollusc. They lay this on the surface of the mud and hammer it with their beaks until the shell smashes and they can reach the succulent flesh.
Young oystercatchers quickly learn how to take worms. A wriggling head is an obvious target and a swift and accurate strike brings an immediately gratifying mouthful. Within six or seven weeks, the youngsters belonging to these families are catching worms for themselves. The skills needed for collecting mussels take longer to acquire. Adults demonstrate the technique to their young and patiently continue to help them feed in this manner for as much as a year until their offspring get the knack. There are, however, two schools of thought among oystercatchers as to the best way to extract a mussel. Smashing the shell is one method, but if you have a particularly sharp bill then it is possible to push it between the two halves of the mussel shell and cut the muscle holding them together. This is more difficult to do but, once the skill has been mastered, it demands less effort. However, a bird taught to be a shell-smasher cannot easily become a shell-opener because using a beak as a hammer blunts it and it may take two weeks to convert the tool needed for one way of feeding into that which is required for the other. So not only have oystercatchers, as a species, their own special diet, but different clans within the species have their own traditional ways of preparing it.
On muddier shorelines, when the water is only a few centimetres deep, food can be gathered by dabbling. The shelduck does that by walking slowly forwards, swinging its head from side to side. The avocet also finds prey here. It is more selective than the shelduck and holds its uptilted beak slightly open as it scythes it to and fro, feeling for small worms and other invertebrates.
The deeper waters immediately beyond the tidal zone are among the richest areas of the sea. Nutrients washed down from the land by the rivers promote a rich growth of floating algae, the phytoplankton. This is food for small fish which in their turn become the food of bigger ones. And birds from the coast fly out to gather them all.
Gannets and boobies use the same technique as the kingfisher does in freshwater. They dive. In the early morning, parties of boobies leave their roosts on the rocks of the sea cliffs that they have whitewashed by their droppings, and set out to survey the surface of the sea. They travel, often in parties of a dozen or so, flying in line astern and close to the surface of the waves. If they come across an isolated fish, one of them may fly up high and dive down into the waves to seize it, but their main targets are shoals of thousands of small fish, often no more than a couple of inches long and brilliantly silver.
Swimming in a shoal is a form of defence for the fish. An individual has a better chance of surviving an attack by a predator if it is swimming alongside a thousand others than travelling by itself, lonely, isolated and vulnerable. But on the other hand, the whole conglomeration of fish is a very obvious and tempting target for any hunter that discovers it. Big predatory fish lunge into it with snapping jaws and drive the shoal as a whole towards the surface. The mass of the silver bodies creates a pale green patch on the surface of the blue sea. That is the sign for which the boobies are searching. One after the other, they dive on it. Other boobies spot the action from afar. The feeding frenzy begins.
Within a few minutes, a great whirling cloud of birds forms above the shoal. As they begin their dives they pull back their wings and take the shape of an arrowhead, thus reducing air resistance but retaining their ability to steer as they take aim. At the last moment, within a foot or so of the water, they fully extend their wings backwards and hit the surface at 100 kilometres an hour. At such a speed, the impact with the water must be very violent, but the boobies have a network of air sacs just below the skin in the front of the body which absorbs much of the shock. Nor is water driven into their nostrils for these are permanently blocked and the birds breathe instead through the corner of the mouth. Their dive may carry them down several metres below the surface. They snap at the fish, usually on the way up again and normally swallow it underwater. Back on the surface, they join a raft of others that have completed their dives and rest for a few moments.
Other birds continue to arrive in droves. Presumably individuals over a kilometre or so away may be able to see the commotion and hasten to the spot to join in, but parties from all over the ocean arrive in such numbers so swiftly from all directions that it sometimes seems as though they have another sense that tells them what is going on. The shoal of fish, harried from below and attacked from above, shifts to and fro in the sea. As it comes nearer the surface, paling the water, increasing numbers of birds are spurred into frenzied action and they dive into the sea with the speed and rapidity of bullets from a machine gun. Each strike raises a plume of white water 30 centimetres high. The feeding may continue for half an hour or more until eventually the shoal is either dispersed or manages to get past the predators circling below and descends into deeper water where at least it is safe from attack from the air.
Among the birds that join these feeding frenzies along the Pacific and Atlantic coasts of North and South America, are brown pelicans. They are among the heaviest of all diving birds. They too target individual fish, from 9 metres above the sea. Their dives are spectacular, and they draw back their wings in the same sort of way that boobies and gannets do, but they cannot rival those birds in the depth they achieve. Their bodies are too big and buoyant, so though they hit the water with a considerable splash they cannot reach any fish, even with the tip of their long beak, that is more than a metre down. When they surface, their baggy bills are full of water as well as fish. To get rid of the water, as they must do before they swallow their catch, they have to open their bills slightly. Other birds not so skilled in diving as the pelicans, such as gulls and noddy terns, will be waiting for that moment. Some may even perch on a pelican’s head, knowing that eventually the pelican will have to open its bill. And when it does, they try to snatch a fish.
Another species of pelican, the American white pelican, also patrols the coastal waters of the southern United States. It fishes in teams. A party of a dozen or so will alight on the surface of the water and take up a horseshoe formation. In line abreast, they swim slowly forward, periodically opening their wings and plunging their bills into water with that perfect unison in which pelicans seem to delight, whether they are flying or fishing. Fish are driven ahead of them until eventually, the two arms of the horseshoe close and the birds, again with impeccable timing, all dip their heads together and scoop up the encircled shoal.
Neither plunge-divers nor scoopers swim underwater in the sea to any significant degree. But the auks, a family of seabirds which includes guillemots, puffins and razorbills, do actively swim to considerable depths. They propel themselves, not with their feet as divers, grebes and some ducks do in fresh water but with their wings, beating them in the same sort of way as they do in air. But water is very dense and it is only possible to beat wings underwater if they are short and stubby. Wings with such a shape, however, are not very effective in air and have to be beaten very rapidly indeed if they are to keep a bird airborne. Guillemots, consequently, are very poor flyers. To rise from the water, they have to whirr their wings at great speed and even when they level off, their flight seems little better than panic-stricken.
Penguins have given up the compromise. They have abdicated entirely from the aerial life. Their reward is that they are now incomparably the best swimmers among birds. They are so skilled, they can even outswim many fish. The biggest of all, the emperor penguin can stay underwater for as long as fifteen minutes, swim down 500 metres and when foraging reach speeds of over 16 kilometres an hour.
We tend to think of penguins as birds that stand around on ice floes and swim in the near freezing waters of the Antarctic, but several species live in warm waters around the coasts of Australia and South Africa and one lives actually on the equator, in the Galapagos Islands. So in terms of geographical spread, the typical penguin does not live in the extreme cold. There is also a good reason to think that the ancestral penguins were relatively small birds. They must certainly have been capable of flight and no doubt combined that with swimming, as guillemots do today. But flipper-shaped wings fail altogether in air if a bird weighs more than about a kilo. So it is likely that the first penguin was closer in size to the little species that lives on the equator in the Galapagos than the 120-centimetre-tall emperor of the Antarctic.
Some species of penguins spend as much as 85 per cent of their lives in the water and now have lost several of the adaptations that enabled their ancestors to colonise the skies. Their bones are no longer hollow and lightweight but solid and heavy, so a penguin is not buoyant and can remain below water with ease. The feathers, once broad with filaments that hooked together to form a vane, have also greatly changed their character. Chilling is of particular concern for a bird that spends most of its time in water even if it does live in a relatively warm part of the world, and penguin plumage has become almost furry. The feathers do not grow in tracts between areas of almost naked skin, as those of most birds do, but are uniformly spread and very dense all over the body. Each feather is short and stiff and has a second short shaft covered with very thin downy filaments that together form an undercoat. On land, where temperatures can fall very much lower than they do underwater, the birds can hold these stiff feathers slightly away from the body so that they trap a layer of air next to the skin. In water, they lie flat and become a coat so dense and well anointed with preen oil that water never penetrates it. Since penguins have abandoned flying, they no longer need to keep their weight down and some of the Antarctic species also have a layer of fat 2 to 3 centimetres thick, immediately beneath their skin, which provides added insulation.
The penguin tail is no longer used as a rudder as it is among flying birds, and has become reduced to a stump. Steering is done with the more robust webbed feet that are placed on either side of the tail and so far back on the body that even the lame hopping of the diver is impossible for a penguin. They have two options for getting around on land. They can fall forward on to their bellies and toboggan over smooth ground or snow by kicking out with their feet; or, as they usually do, they can stand vertically, using their stumpy tail as a prop when stationary and plod around upright, flippers clasped to their sides, with that impassive solemnity that makes them, in our eyes, so endearing.
The big penguins of the far south make very long voyages in search of their food. The king penguin has been seen as much 160 kilometres away from its breeding colonies; the emperor, though it does not venture beyond the cold waters of the Antarctic, may travel a thousand kilometres on a single feeding trip. But some birds fly very much farther across the face of the open ocean. Storm petrels, little birds scarcely bigger than swallows, feed on floating particles so small that they can hardly be seen by the human eye. To pick them from the surface of the water, they face into the wind and hold their trembling wings outstretched to keep themselves aloft while trailing their long delicate legs in the water to prevent themselves being blown backwards. In this position, they hover like ballet dancers on points, sometimes making pattering runs, sometimes little hops and two-footed skips as they peck at the plankton in front of them. From a distance it looks as though they are tip-toeing across the surface and it is said that this matching of St Peter’s miraculous if short-lived accomplishment gave them their name.
The distribution of plankton is very patchy but petrels do not rely simply on chance to find it. Their family, which includes shearwaters and albatrosses, have tube-shaped nostrils at the base of the beak and, unlike most other birds except the turkey vulture, they have an excellent sense of smell. Just as scent guides individuals back to their own nest burrows at night during the breeding season, so it helps them find food out on the open ocean. When fish or shrimps feed on plankton the tiny plants release a chemical substance and it has recently been discovered that even the faintest whiff of it will attract petrels.
The widest ranging of all ocean-going birds are the albatrosses. They do not dive like the boobies, nor patter across the surface like the petrels. They swoop down and sit on the water and from there catch bigger creatures such as squid which rise at night. They also take any carrion they can find. Their superb gliding skills enable them to soar over the waves with minimum effort and they can remain in the air for months on end, sleeping on the wing. They may fly right round the globe, circumnavigating the Antarctic continent by exploiting the prevailing winds and travelling for 1,600 kilometres on a single food-gathering journey.
But even albatrosses have been unable to break their link with the land. Their need to nest shackles them to it; and their chicks’ demand for food compels them to return to it repeatedly. The chick of the biggest of them, the wandering albatross, remains dependent upon its parents for twelve months, so in spite of their ocean-going capabilities, adult albatrosses have to return to land throughout their lives and when feeding their young may do so every few days.
One bird has managed to break this tie to a land-bound chick. It has not yet developed a way of laying its eggs at sea; nor has it succeeded in doing so in the air, as it was once believed that a female bird of paradise could do by depositing it on the back of a perpetually flying mate. But once the chick has hatched, the parent does not return to land again that season. Instead, the chick takes to the sea. To that extent, this species must be counted the most truly oceanic of all birds. It is the ancient murrelet.
Murrelets are small relatives of the birds that are known in North America as murres and in Europe as guillemots. It is called ‘ancient’ because, unlike any other member of its family, it has grey on its shoulders like a shawl worn by the elderly. It nests on islands around the northern rim of the Pacific. Small numbers are found in Japan and Kamchatka but its main nesting areas are on the islands off the western coast of North America.
Frederick Island, a small fragment of land facing the open ocean just off the coast of the Queen Charlotte’s Islands in British Columbia, is the site of one of its largest colonies. If you land there in the last week of May or the beginning of June, you will see a few shore birds, oystercatchers, gulls and – significantly – bald eagles and peregrines. When you walk inland, you enter a tall dark forest of giant conifers – hemlock, cedar and pine. The rainfall here is so heavy that the whole of the forest floor is cloaked by thick luxuriant moss. It drapes the rocks, the peaty soil and the tangle of fallen trunks, softening and concealing all angularities as a heavy fall of snow will do. But here there are even fewer birds to be seen. You may hear the faint high-pitched whistle of a winter wren or occasionally the harsh croak of a crow or a raven. But around you, hidden in small underground burrows, in the soil beneath the logs or at the base of the trees, and in the crevices between the boulders, are at least eighty thousand ancient murrelets brooding their eggs or guarding their young.
They have good reason to hide. The peregrines and the eagles, even in this relatively dense forest, have no difficulty in pouncing on a bird out in the open. An adult therefore only makes the journey to or from its nest burrow under the cover of darkness. Frederick Island, however, is so far north that the summer nights are brief and seldom very dark. As a consequence both peregrines and eagles are able to hunt for most of the twenty-four hours of the day. They sit in the twilight on tree stumps or low branches, waiting. The murrelets returning from feeding at sea, come in high and at speed. Their short flipper-wings, that made them so proficient in water, are so inefficient aerodynamically that the birds have to travel fast if they are not to stall. As result, they frequently crash into the branches of the tree above their nest holes and tumble to the ground. They are not very agile on the ground either. With their legs right at the rear of their body, they cannot stand sufficiently upright to be able to run without a desperate flapping of their wings. A pair of peregrines nesting in this forest may catch as many as a thousand murrelets in a single season.
Murrelet parents take turns in brooding the eggs, and change over every three days. It takes some thirty days to complete incubation. Between 5 and 10 per cent of the breeding population is lost every year. Nor are the adults entirely safe underground. There are deer mice on the island and particularly large ones. Murrelet eggs are probably safe from them, for they have such smooth shells that it would be difficult for a mouse to get a purchase on them with its teeth. A newly hatched chick, however, is certainly vulnerable and the parent murrelets never leave any droppings at the mouth of the nest hole or within, as rodents hunt by smell.
At last, the eggs hatch and two little fluffy black and white chicks, with a small white egg tooth on their beaks, huddle together in the nest chamber. The eggs from which they emerged were particularly large and their stomachs still contain a considerable amount of yolk. This sustains them for the first day or so, but it also has to provide them with sufficient energy to tackle the extraordinary marathon that now lies ahead of them.
After two nights in the nest – or only one if the egg hatched early in the morning – an hour or so after sunset, the parent birds emerge from the nest hole and begin calling to their chicks with continuous chirps. The chicks come out running. They tumble over the sheer sides of boulders, they sprint across the beds of green moss, they push their way under logs but never once do their legs stop moving. If you pick one up, its little legs continue pedalling at the same frantic pace as if it were a clockwork toy. Their parents move ahead of them encouraging and guiding them with repeated calls, leading them down to the beach.
It may take as much as ten minutes for them to get out of the forest. All that time, they are vulnerable to attack from mice, peregrines and eagles. They emerge on to the beach where they are even more exposed and vulnerable. Their parents are now floating many metres out from the shore, but they are still calling. The chicks rush into the sea, their legs still moving so rapidly that they rise above the surface of the water and virtually hydroplane. Parents and chicks recognise one another’s calls. United at last and swimming alongside one another, the adults give their valiant offspring their first meal – a little regurgitated fish. By the following morning, parents and young are out of sight of land. For the next six or seven weeks, they will swim together until the young are big enough and strong enough to collect fish for themselves.
Wandering albatrosses may make longer journeys across the face of the ocean; emperor penguins may dive deeper into its depths; but the ancient murrelet has come as near as any bird to severing its links with the land.