Hudson's cuckoo

At the request of the eminent biologist Dr Alfred Russel Wallace, in 1900 the naturalist W H Hudson kept watch on a robin's nest in which a cuckoo had laid an egg. In his Hampshire Days, Hudson describes in mesmerizing detail the innate process whereby the nestling cuckoo ejected its rivals – a single egg and a nestling robin. He was assisted by the young and tender-hearted daughters of the house where he was staying.

The account ends like this:

The end of the little history – the fate of the ejected nestling and the attitude of the parent robins – remains to be told. When the young cuckoo throws out the nestlings from nests in trees, hedges, bushes, and reeds, the victims, as a rule, fall some distance to the ground, or in the water, and are no more seen by the old birds. Here the young robin, when ejected, fell a distance of but five or six inches, and rested on a broad, bright green leaf, where it was an exceedingly conspicuous object; and when the mother robin was on the nest – and at this stage she was on it a greater part of the time – warming that black-skinned, toad-like, spurious babe of hers, her bright, intelligent eyes were looking full at the other one, just beneath her, which she had grown in her body and had hatched with her warmth, and was her very own. I watched her for hours; watched her when warming the cuckoo, when she left the nest and when she returned with food, and warmed it again, and never once did she pay the least attention to the outcast lying there so close to her. There, on its green leaf, it remained, growing colder by degrees, hour by hour, motionless, except when it lifted its head as if to receive food, then dropped it again, and when, at intervals, it twitched its body as if trying to move. During the evening even these slight motions ceased, though that feeblest flame of life was not yet extinguished; but in the morning it was dead and cold and stiff; and just above it, her bright eyes on it, the mother robin sat on the nest as before, warming her cuckoo.

How amazing and almost incredible it seems that a being such as a robin, intelligent above most birds as we are apt to think, should prove in this instance to be a mere automaton! The case would, I think, have been different if the ejected one had made a sound, since there is nothing which more excites the parent bird, or which is more instantly responded to, than the cry of hunger or distress of the young. But at this early stage the nestling is voiceless – another point in favour of the parasite. The sight of its young, we see, slowly and dumbly dying, touches no chord in the parent: there is, in fact, no recognition; once out of the nest it is no more than a coloured leaf, or a bird-shaped pebble, or fragment of clay.

It happened that my young fellow-watchers, seeing that the ejected robin if left there would inevitably perish, proposed to take it in to feed and rear it – to save it, as they said; but I advised them not to attempt such a thing, but rather to spare the bird. To spare it the misery they would inflict on it by attempting to fill its parents’ place. They had, so far, never kept a caged bird, nor a pet bird, and had no desire to keep one; all they desired to do in this case was to save the little outcast from death – to rear it till it was able to fly away and take care of itself. That was a difficult, a well-nigh impossible task. The bird, at this early stage, required to be fed at short intervals for about sixteen hours each day on a peculiar kind of food, suited to its delicate stomach – chiefly small caterpillars found in the herbage; and it also needed a sufficient amount by day and night of that animal warmth which only the parent bird could properly supply. They, not being robins, would give it unsuitable food, feed it at improper times, and not keep it at the right temperature, with the almost certain result that after lingering a few days it would die in their hands. But if by giving a great deal of time and much care they should succeed in rearing it, their foundling would start his independent life so handicapped, weakened in constitution by an indoor artificial bringing up, without the training which all young birds receive from their parents after quitting the nest, that it would be impossible for him to save himself. If by chance he should survive until August, he would then be set upon and killed by one of the adult robins already in possession of the ground. Now, when a bird at maturity perishes, it suffers in dying sometimes very acutely; but if left to grow cold and fade out of life at this stage it can hardly be said to suffer. It is no more conscious than a chick in the shell; take from it the warmth that keeps it in being, and it drops back into nothingness without knowing and, we may say, without feeling anything. There may indeed be an incipient consciousness in that small, soft brain in its early vegetative stage, a first faint glimmer of a bright light to be, and a slight sensation of numbness may be actually felt as the body grows cold, but that would be all.

Pain is so common in the world; and, owing to the softness and sensitiveness induced in us by an indoor artificial life, since that softness of our bodies reacts on our minds, we have come to a false or an exaggerated idea of its importance, its painfulness, to put it that way; and we should therefore be but making matters worse, or rather making ourselves more miserable, by looking for and finding it where it does not exist.

The power to feel pain in any great degree comes into the bird’s life after this transitional period, and is greatest at maturity, when consciousness and all the mental faculties are fully developed, particularly the passion of fear, which plays continually on the strings of the wild creature’s heart with an ever varying touch, producing the feeling in all degrees from the slight disquiet, which is no sooner come than gone, to extremities of agonising terror. It would perhaps have a wholesome effect on their young minds, and save them from grieving overmuch at the death of a newly-hatched robin, if they would consider this fact of the pain that is and must be. Not the whole subject – the fact that as things are designed in this world of sentient life there can be no good, no sweetness or pleasure in life, nor peace and contentment and safety, nor happiness and joy, nor any beauty or strength or lustre, nor any bright and shining quality of body or mind, without pain, which is not an accident nor an incident, nor something ancillary to life, but is involved in and a part of life, of its very colour and texture. That would be too long to speak about; all I meant was to consider that small part of the fact, the necessary pain to and destruction of the bird life around them and in the country generally.

Besides being a fine writer, it seems Hudson was also a fine and kindly teacher: and what lucky children they were to have him at hand. The natural world offers the percipient an infinity of situations, relationships and dramas. Meditation upon them leads at last beyond mere science to religion; this excerpt will chime not only with the Buddhist and Hindu, but with those of us trying to understand the meaning of the Crucifixion.

Hudson was one of my earliest influences. If you’d like to read him, try Far Away and Long Ago, or indeed Hampshire Days itself: I lived for nearly twenty years near Selborne, and his descriptions of that district still ring absolutely true.

Building the mosaic

The human retina has two sorts of photoreceptors. Rods (so called for their shape) respond only to dim, monochromatic light, while cones are adapted to the perception of colour and detail. The middle of the retina is formed into a small pit, the fovea. Here the cones are densest; and in the middle of the fovea is an area about a third of a millimetre in diameter, called the foveola, where the concentration of cones is greatest of all.

Rather than perceiving something in detail all at once, we scan it. The musculature of the eyes makes a series of tiny jerks, termed saccades, shifting the foveola from one point to another. In this way the brain builds up a mosaic which the imagination and memory try to make sense of.

Hearing operates in an analogous manner, using a granular series of pressure waves. In fact the whole of our perception works like this.

What we do with the mosaic depends on who we are. Our genetics, prejudices and past experiences are all brought to bear when integrating and interpreting information.

Yesterday I walked the path fringing the harbour. The tidal surge that recently wreaked havoc on this coast has left behind huge quantities of brash – the brown and decaying remnants of marsh plants, mixed here and there with branches of seablite or gorse, driftwood, plastic debris, gates, fencing, boats large and small, even an errant, crazily-angled footbridge. The path is still muddy, but under a mild south-westerly breeze and an even milder February sun it was beginning to dry out. Spring is returning to this hemisphere. The birds know it; but the season is still winter.

The sky was azure, the clouds white, the sea ultramarine. Far away across the estuary, on the sands at the end of the shingle spit, many seals were basking. The profile of the bottom there forms a trap for fish. Those mobile specks, too distant to identify, were fish-eating birds: mergansers, goldeneyes, Slavonian grebes, red-throated divers, perhaps black-throated and great northern divers as well (all were reported later). The scene was alive with birds, a thousand or more brent geese, innumerable gulls, cormorants, swirling clouds of waders – knot and dunlin, mainly, no doubt. For me, with my history and interests, an arc of excitement was building.

At length the path brought me to the fen, a wide, quiet, reed-fringed lagoon behind the sea wall, with inlets and spits where birds can hide, rest and preen. On my preceding visit a single avocet, an early harbinger of spring, had been swimming there and upending like a duck. Now there were forty. The lapwing flock had dwindled; the golden plover had gone altogether, and in their place were black-tailed godwits.

Because I had left my telescope at home, I spent a long time scrutinizing the fen with binoculars only. It is surprising how much information the foveolas can glean, even at low magnification. I sorted through the geese on the far side, admired the pintails (surely there is no more elegant creature than a drake pintail), examined the many black-headed gulls for something rare, counted the godwits and avocets, jotted notes. Just when I thought I had covered everything I picked up a single drake pochard, feeding where the water is deepest.

Descending the wooden steps, I gained the footpath that skirts the western side: I had decided to walk even further, to check the freshwater meres near the coast road. The footpath is thickly lined with scrub and small trees, but here and there affords views of the fen.

My afternoon was assembling grain by grain, like the pixels on this computer screen or the frames of a cinema film, like the words of a story or even the letters of a sentence. I was content, more than content, with my reward for the long walk. This landscape has always suited me very well, and if the day had offered nothing more I should have gone home happy.

I stopped once more to raise my binoculars to the fen. They were filled with leafless willows, a tawny wall of dead reeds, gunmetal water, all sunlit from the right, the colours perfect. Then, low above the reeds, I saw the thuggish bulk of a female sparrowhawk coming slantwise in my direction. Her brown plumage co-ordinated exactly with the waxen twigs and branches of the willows. In an instant she was lost to view behind the foreground hawthorns.

A bird of prey is a solitary assassin, living fast, much of its time yielded to the imperative to feed. An evolutionary arms race joins predator and prey: most attacks end in failure. As the winter afternoon wanes a hungry hawk can become desperate and even reckless.

Sparrowhawks hunt in various ways. A common ploy is to cruise the length of a hedge and flip over it to surprise whatever is on the other side – a blackbird or even a wood pigeon, for a really strong female hawk. This one was using the reedbed like that.

For an odd, floating moment I was the only one who knew she had arrived. Then most of the birds on the fen took flight, many more lapwings than I had been able to count, avocets, gulls, even some of the teal and wigeon; the rasping cries of a fleeing snipe came from high above the willows.

I could not tell whether the hawk had struck, and didn’t see her again, but my glimpse of her had unified what had gone before. It was the final piece of mosaic. The naturalist longs to blend with nature, to learn its secrets, a hopeless quest but one that always draws him on. Just for those two or three seconds before the fen erupted, I was as much hawk as human.

It bears saying that each of has unique experiences, all the time. Each of us is building a unique vision of the world. If I had no interest in birds, or had simply been looking the other way, my afternoon would have felt quite different. And your past few minutes would have felt different too, because you would not have been reading this, but assembling some other mosaic, in keeping with the larger mosaic that conforms to the unique combination made by your genetics, history, and system of beliefs.

A late call

Image: axelkr on Flickr

Sitting reading late last night, I heard, briefly in the drizzle, and above the soughing of the pine branches, a whinnying sevenfold call: tititititititit, so soft and fleet that it was barely audible at all, but I fancied its maker was heading north. A passage whimbrel, or whimbrels, high over these chalk Downs, twenty miles from the estuaries of the Sussex and Hampshire coast.

During May whimbrels gather at Pagham, at Chichester and Langstone Harbours. There they feed, far out on the mud with the other waders. The rising tide drives them to congregate on islands and undisturbed places on the shore. They are torn between two urges, to recuperate and to go on. The far north is their magnet; that is where they breed. Sometimes, as day draws to a close, you can almost see the indecision in a flock of six or ten or twenty. At last they will take wing and head inland.

Much of their migration is done at night. The calls keep the birds together, and are unique, just as all the other shorebirds have their unique voices, evolved over millennia of co-existence.

Last night it seemed to me, and seems to me still, that the shorebirds’ calls are one of life’s verities. They are genuine, unpretentious, authentic, and sensible and practical too, unlike most of the doings of men. That faint cry from the wet, cloudy darkness reconnected me for a moment with nature, and my evening was transformed.

Collared Doves

Image: Horia Varlan

The practice of keeping dovecots is now largely a thing of the past, which is rather a shame, because a few white doves add greatly to the charm of a garden or courtyard. Better than domestic doves, though, are those born and bred to the wild. They make ideal “pets”, because they are free to leave at any time, and there is none of the compulsion which to my mind mars the usual relationship of human with animal.

Unless you are very unlucky, you will have your own wild doves – Collared Doves – not too far away: slender, stone-coloured birds with a distinctive cooing song. They are fond of suburban back gardens, smallholdings, farmyards, and similar places, and where unmolested can become quite tame.

At a distance a Collared Dove looks almost uniformly greyish brown, but seen close to, especially in sunshine, it is a most elegant and attractive bird. The plumage is very delicately contoured and shaded, and a softly vinous flush on the breast harmonizes perfectly with the claret-coloured legs and feet. The eye, too, is in this register of red: when the sun catches it at a certain angle, it looks exactly like a ruby.

In its flight and habits the Collared Dove is a gentle, fastidious creature; the partial black collar, edged with white, is reminiscent of the velvet chokers once worn by dowager duchesses. The impression is completed by one of the bird’s often-used calls, a loud uhrrr, uhrrr! uttered as if in horror at the violation of its genteel sensibilities by the appearance of some unspeakably uncouth ruffian – perhaps even a flasher.

The Collared Dove has become so much a part of the local scene that it is hard to believe it bred in this district no earlier than 1966. The first arrivals were the subject of a series of excited notes on a brand-new card in my index box. The magic date was 25 May 1966, when a male was seen – studied at 30x through my telescope! – and heard singing on the roof of the house. By 4 June it had a mate and both birds remained in the area till the end of the year. Definitely not a domesticated form. Very good views frequently obtained when seen drinking from gutter 15’ from window. Wary and unapproachable.

Few bird-watchers now would bother to record “very good views” of the Collared Dove. But how and why has this bird become so common where previously it was unknown?

Nothing is ever static in the living world. Even the most apparently stable community of plants and animals is in perpetual flux, brought about by changes in climate or other environmental factors, or by changes in their own genetics and evolution. Change is in fact one of the chief characteristics of living things.

Normally this change is quite slow, taking the span of many human lifetimes to become obvious. Sometimes, though, it can be quite rapid, and occasionally, as in the case of the Collared Dove, it can be spectacular.

The most sudden changes come in the wake of some catastrophe, a natural disaster such as a forest fire, an earthquake, or volcano, which wipes out one community and gives a clean slate for the formation of another. Or the natural disaster may simply destroy one part of the community and alter its balance, allowing certain new forms to invade.

Man’s influence on the environment can be seen as a series of natural disasters, both large and small, of this second type. Many species have lost out; some have gained from the opportunities inadvertently put in their way. When a species not only has a new set of opportunities put before it, but simultaneously undergoes a genetic or behavioural change enabling it to exploit new territory, then you can expect some fireworks.

The Collared Dove was originally a bird of the Indian sub-continent. Its principal food is grain, which pre-adapted it to benefit from Man’s increasing use of agriculture. As farming slowly became more successful the Collared Dove began to spread slowly north and west, reaching Asia Minor in the 16th century. By 1925 it was well established in the Balkans.

Then, suddenly, something happened. It may have been a slight genetic change enabling some individuals to breed more successfully; it may have been a behavioural change making the Collared Dove even more tolerant of Man. Whatever did happen, the slow northward expansion of the previous few centuries became a full-scale invasion.

A record of its progress across Europe looks like one of those animated maps showing the advance of the Nazis: from Belgrade it reached Hungary in 1928 and Czechoslovakia in 1935. Austria fell in 1938, Poland in 1940. It reached Germany and Italy in 1944, Holland in 1947, Switzerland and Sweden in 1949. By 1950 it was breeding in France: the first (unofficial) British sighting was in 1952, the first breeding record in Norfolk in 1955. It first bred in the London area in 1962, and in our own district, as already mentioned, in 1966.

The earliest colonists were often to be found in the vicinity of chicken-runs, or at zoos or other places where spilled or otherwise free grain was to be picked up. This opportunism in feeding is one key to the Collared Dove’s success. Another is its liking for conifers in which to nest – almost to order we busily planted our suburbs with Lawson’s Cypress, ready for its arrival.

But the main key to its success is its fecundity. In mild weather the breeding season may begin as early as January and go on till October. It can tend the young of one brood while incubating the eggs of the next, and will tolerate levels of disturbance that would make most other birds desert.

The increase is still going on. In Britain it is extending its range into other habitats, especially farmland. Abroad it is still moving north and west, having reached Iceland, where this gentle invader may even be readying itself for the final, really big challenge, the one that even the Nazis couldn’t get near: Canada, the USA, and all points south.

(Introduction to these pieces; see all)

Black-headed Gull

Image: Gidzy

As summer comes to its close, the annual influx of gulls gathers pace. By autumn they are everywhere in the district, feeding on pasture and arable and parkland, by and on water of all kinds, and, ever on the lookout for a meal, patrolling the skies above back gardens and industrial sites.

There are five common sorts which visit us here, and the commonest of these is the black-headed gull. This is the smallest and the slenderest of the five, and can be told by its red bill and legs, and the long white triangle on the leading edge of the wings, which have pointed rather than rounded tips.

Despite its name, the black-headed gull’s head is not black. In spring and summer the adult has a chocolate-brown hood, which is moulted in autumn to leave the head pure white except for two dark smudges, the larger one behind the eye and the smaller one just in front of it. The immature bird is more mottled in appearance, but still has the white triangles on the wings and, at all seasons, the smudges on the head.

In grace, buoyancy, and agility of flight the black-headed gull has few equals among our winter birds. During autumn it makes a habit of following the plough, and a hundred or more at a time can be seen swirling like snowflakes against the freshly turned soil. The same sort of prey – wireworms, millipedes, earthworms, and so on – attracts it to football fields and similar grassland; but our local black-headed gulls find their shangri-la on pasture that has just been sprayed with Hydig, the fertilizing sludge produced at Maple Cross sewage works, just south of Rickmansworth.

The sewage works themselves are also an attraction for gulls. In the grounds is a disused gravel pit which, during the 1960s, was filled with solid matter rejected during the purification process. A long black outfall pipe led from the works into the middle of the pit. Some of the outfall consisted of sand, so that the pit slowly became silted up, but it also contained grain, as well as a comprehensive assortment of the things that get dropped or thrown into the lavatory (among them many children’s toys such as rubber Donald Ducks, combs, nailbrushes, pairs of spectacles, and any number of sets of false teeth.)

Among all this detritus the gulls used to gather, picking over the spoils. At irregular intervals there came a distant rumbling in the pipe. At this the gulls’ excitement mounted, and with expectant cries of “kwarr” the flock drew closer to the broad mouth of the pipe, flying up when, with a rush, it disgorged a fresh supply of sludge.

During hard weather this was an important source of food for the gulls in the Colne Valley, and as many as 400 birds could be seen there at once. The dumping has finished now, but the sewage works still draw plenty of gulls. After detailed observation the same individuals can be recognized returning day after day, for some birds have peculiarities such as a deformity of the bill or an odd pattern of plumage. A few of the gulls carry aluminium leg-rings, put there by ornithologists perhaps in other countries.

One ring seen on a living bird bore the number C-17122 or C-1722. From this and a description of the pattern the British Trust for Ornithology were able to say that the ring was of Finnish origin, and in fact many of the black-headed gulls which winter with us breed in the countries round the Baltic Sea, especially Sweden and Denmark.

In Britain the black-headed gull breeds, especially in the north, on saltmarshes and sandhills close to the sea. Yet it is also the most inland of our gulls and nests on marshy islands in lakes and moorland pools far from the coast. In the early 1960s a few pairs even bred at Maple Cross, but the colony was soon abandoned.

It is difficult to imagine today that all gulls, even the black-headed, were once very rare in this area, being seen only when storms at the seaside blew them off course. Their success is attributable directly to man: they have learned to exploit the many opportunities, like the sewage outfall pipe, we have unwittingly put in their way.

The only problem for gulls inland is the need of a safe roost. The first gulls to appear in any numbers in London arrived in the bitterly cold winter of 1894-5, and they roosted then mainly on the Thames at Chiswick Eyot, or at the small Lonsdale Road Reservoirs.

At the turn of the century there was a big increase in reservoir-construction. The huge Staines Reservoir was completed in 1902 and quickly became a major gull roost. The other reservoirs in that part of Middlesex and north Surrey, some even bigger than Staines Reservoir, as well as a chain of reservoirs in the Lea Valley, provided further roosting. Today well in excess of 100,000 gulls roost in the London Area during winter.

When it was filled, in 1955, Hilfield Park Reservoir near Aldenham soon became an important roost, attracting something like 5,000 birds. Many of our local gulls roost there, and at dusk make their flight-lines in that direction. The rest of our birds roost, or did roost, at Staines, and the birds from the Colne Valley can be seen flying south at the end of day. This is where the Maple Cross birds roosted, arriving there 25 minutes after first light, having taken that time to fly, at 40 m.p.h., the distance from Staines.

But now these opportunists have found a way to cut their commuting time. A vast gravel pit, Broadwater, has been dug at Denham, large enough to make a safe roost, and many Staines-bound gulls have adopted it as their own.

A gull roost as it fills is an extraordinary sight. The sheer spectacle of so many birds in one place is not soon forgotten. To see them arriving, each with a different experience of the day’s foraging, is a powerful reminder of the adaptability of living things and the effect that man has had on their world.

As the gulls come in, you tend to forget about their feeding habits and are conscious only of a sense of wonder and beauty. If only all our activities produced a result like that.

(Introduction to these pieces; see all)

Spotted flycatchers

Image: Andrew Easton

A new little bird appeared yesterday morning at the corner of the road, perching on a telephone wire high above the pavement. It first attracted attention by its call – a characteristic wee tuc-tucc, wee tuc which, once heard and learned, is never forgotten.

The owner of this cry is just the sort of small brown bird to puzzle the beginner, with mousy plumage above, paler underparts and a few dark streaks on the breast. But its upright, watchful posture and, above all, its behaviour, confirmed the identification at once.

From its perch on the wire the bird made repeated swooping sallies at flying insects, swerving in mid air to return to the same spot. After a short rest it ventured forth again, returning this time to a bare twig in one of the trees that line the road here.

Gilbert White, in his letter to Thomas Pennant of 4 August 1767, says: “The stoparola of Ray (for which we have as yet no name in these parts) is called, in your Zoology, the fly-catcher. There is one circumstance characteristic of this bird, which seems to have escaped observation; and that is, it takes its stand on the top of some stake or post, from whence it springs forth on its prey, catching a fly in the air, and hardly ever touching the ground, but returning still to the same stand for many times together.”

The good curate of Farringdon, in Hampshire, was as precise in this as in all the observations contained in his Natural History of Selborne: the bird on the corner was indeed a fly-catcher: a spotted flycatcher, to be exact, the Muscicapa striata of our zoology.

It was still present this afternoon, although it had moved a few yards along the road. It is on its way to Africa for the winter and, as flycatchers do, has taken a sudden and unaccountable liking to this place.

The preference of the flycatcher for one location over another is something of an enigma. On the one hand the bird tolerates man, often building its nest close to a busy path; on the other it seems attracted by the tranquillity of an unfrequented garden or woodland clearing.

One pair which nested in a small copse adjoining the school swimming bath were, with their fledglings, much in evidence when no one was about, perching now on the close-boarded fence by the grass, now on the diamond-mesh fence running from the changing shed to the filter house. The sound of the filters, the smooth surface of the deserted pool, the blue reflections and refractions, the dense foliage of the oaks and lindens of the copse: all this gave the place an air of magical seclusion of which the flycatchers seemed to form a natural part.

They were brought here by the many insects attracted to the water. Even when the flycatchers’ domain was invaded by a solitary swimmer they continued to feed. But as soon as more people arrived, the birds withdrew, emerging again only later when peace resumed.

Flycatchers are like this in gardens too. Best of all is a garden untenanted, overgrown, with plenty of neglected corners to bring the insects and a sufficiency of bare twigs for feeding-perches. Next best is a garden frequented, if at all, only by one or two gentle souls with trugs and secateurs. The passage flycatchers appear at hedge-clipping time. They do not object to the click of hand-shears, but vanish at the whine and rattle of electric cutters, or at the noise of all the other mechanical abominations with which even the smallest garden now abounds.

Yet the spotted flycatcher is one of the few species – the others are the chaffinch, great and blue tits, song thrush, blackbird, dunnock, and wren – that can thrive in the gardens of Inner London. They are able to do this because their requirements for food and nest-sites are comparatively unaffected by lack of undergrowth. Flies may be found almost everywhere, and their catchers are content to nest on a beam or branch close to a wall or tree trunk, or in a crevice in masonry. Thus flycatchers are among the few species able to breed in the Royal Parks or in the squares of Mayfair or Bloomsbury.

There is another sort of breeding British flycatcher, the pied flycatcher, with a more westerly distribution. This bird has been seen in the district only on a handful of occasions, usually on autumn passage. The spotted and the pied are typical of the flycatchers found in Europe, with flat, rather broad bills surrounded by bristles which help direct the prey into the gape.

Elsewhere in the world, especially in the tropics, there is a large and diverse array of birds of the flycatcher tribe. Some are brilliantly coloured, as small as wrens or as large as thrushes; many have habits nothing like those of our own native species. In New Guinea, for example, many of the fifty or so breeding species behave more like warblers, chats, or even shrikes than flycatchers. In Madagascar live species which live sociably in the tree canopy, just like our native blue tits and great tits. In south-east Asia are flycatchers which keep to the shadows of the undergrowth, like our robin.

But they all share a certain special elegance and grace, and give a peculiar impression of rightness in their habits and form. The flycatcher on the corner, by choosing this place for his halt on the journey south, has, in his own small way, conferred on it the accolade of his approval and made it better than it was before.

Probably he will be there tomorrow too, but the following day he may well be gone, leaving behind a sense of flatness, emptiness, and loss: a sense of impending autumn.

(Introduction to these pieces; see all)

Preening

Image: Hariadhi

The old stone bird-bath is much weathered now, cracked by past frosts, and in places its square, layered pedestal has become encrusted with grey and yellow lichen. It stands at a point in the garden a fair distance from the house, in the middle of a quartet of rose-beds virtually surrounded by yew hedges. On three sides there are trees of varying sorts and ages, some quite large.

Human disturbance is minimal; there is no dog in the household, and the only cats are occasional and unwelcome visitors from neighbouring gardens, so the place is a haven for birds. Kept topped up daily with the watering-can, a bird-bath provides a focal point for the garden and an endless source of movement and interest.

The most compulsive bathers are starlings, which create a tremendous amount of spray as they attack the water with their wings. Just now, in mid July, the greyish-brown juvenile starlings are especially numerous, and crowds of them are all trying to get into the water at once, leaving the less pushy dunnocks and song thrushes waiting on the grass nearby.

From time to time, when the starlings permit, almost all the birds in the garden will come down to drink or bathe, and this is often the best chance to get a view of shy or otherwise hard-to-see species. This afternoon a blackcap has been down, as well as a willow warbler and, earlier, a great spotted woodpecker.

They expose themselves to view because they must. Bathing for these birds is essential to maintaining the plumage in good order. Its function is not primarily one of cleansing, but of preparing the feathers for what comes next. Indeed, most birds are careful to avoid getting their plumage drenched, because this eventually renders the feathers brittle and, more importantly, robs the bird of its power of flight.

The water-bath is a carefully controlled wetting, spreading an even layer of moisture over the feather surfaces. Having repeatedly ducked its head into the water and flicked spray over its back, the bird performs special shaking movements to rid itself of surplus water. The exact pattern of these movements varies from group to group; some birds, such as gulls, can shake their feathers even while flying.

A bird like the blue tit is typical of the garden bathers. Immediately it has finished at the water, it retires to a less exposed position in order to preen in safety.

The great majority of birds have a special gland just above the root of the tail. The gland secretes oil which keeps the feathers supple and waterproof. Preen oil has another function too. Birds, like humans, cannot synthesize vitamin D inside their bodies. We manufacture it in our skin, provided we are exposed to the sun. Vitamin D synthesis likewise takes place in the oil; the vitamin is then either absorbed through the skin or ingested by the bird while preening.

The first act of preening is to stimulate the oil gland with the bill; oil is then quickly transferred to the plumage with quivering and stroking movements. The bird must work fairly rapidly because the oil hardens on exposure to air. The fact that the feathers are damp delays the hardening and enables the oil to be spread more evenly.

Having made a quick distribution of the oil, our blue tit, as soon as it has the opportunity, moves on to the next, longer and more leisurely, phase of preening. The outer feathers are ruffled up, to make them easier to get at, and each area receives its share of meticulous attention. A bird’s plumage is one of its most important assets, and much time each day is devoted to its care, both in these special sessions and during any odd moment.

There are two main types of preening movement. With the bill closed the bird sleeks down disarranged feathers and flicks away foreign particles. With it open, individual feathers – especially those of the wings and tail – are lightly combed.

The structure of a feather is a miracle of design. A large flight feather consists of a central shaft fringed on each side with about a hundred filaments, each of which, in turn, is fringed with smaller filaments or barbules. Each barbule has several hundred minute hooks which interlock with neighbouring barbules; there may be a million such hooks in a single feather. The combing action helps to restore the interlocking pattern and produce once more a smooth and continuous vane for flight.

Besides preening, birds in the garden may be seen maintaining their feathers in other ways. A favourite pursuit, especially of thrushes and blackbirds, is sunning. The bird, feathers ruffled and wings drooped, squats with its back to the sun, apparently just enjoying the heat: but the light helps to disturb parasites among the feathers, and makes them come out into the open where the bird can preen them away. A more extreme sunning posture has the bird sprawled with one wing fanned out towards the sun, its body tilted sideways and the tail swung round to the same side.

Dust-bathing is also indulged in by some birds, including sparrows and wrens. Its purpose is not clear, but may also have something to do with discouraging skin parasites. The same is true of the strangest feather-maintenance practice of all, anting.

In this the bird puts ants among its feathers, or simply squats over an ants’ nest, allowing the ants to crawl into its plumage. It is thought that the exudations of the ants, like preen oil, help to keep the feathers in good condition. The type of ant usually chosen secretes formic acid when it is angry, which certainly acts as an insecticide, and the ants themselves may attack any parasites they come across. Hundreds of species of perching birds have been observed anting, but starlings, crows, and especially jays, are particularly addicted to it.

In fact there are starlings on the lawn at this moment, taking ants from a nest halfway down the path.

This is the kind of ornithology anyone can study, whether from a window or a deckchair. All you need is a sharp pair of eyes – and a bird-bath. It need not be elaborate; an old dustbin lid will do, as long as it provides a shallow gradient and its site a measure of seclusion.

(Introduction to these pieces; see all)

Lapwings

Image: Mirko Thiessen

This is shirt-sleeve weather, a day to increase still more the contrast between your forearms and the band of pale skin under the watch-strap, the sort of day when the lubricant loosens in the focusing barrel of your binoculars. The blueness of the sky has been taken up by the air itself. Each detail of the scene appears almost supernaturally clear and sharply defined, given somehow an even greater clarity by the fresh breeze hissing in the leaves of the lakeside alders.

Summer is officially less than a week old, but for some among us autumn is already here. The return migration of the lapwings is nearing its height. During the next two or three months many thousands will pass through the district, slowly making for their winter quarters in the south and west.

Lapwings are birds of the plover family, quite large, seeming black and white at a distance, with wispy crests and characteristically rounded wingtips. They breed in open places, especially on farmland, and can be seen in spring performing spectacular aerobatic display-flights, twisting and tumbling, keeping up a barrage of wheezing cries: frenzied variations on the ordinary note of pee-wit from which the lapwing gets its other common name.

Our breeding birds may winter as far away as Spain, while others visit us in winter from the continent. The movements are quite complex and difficult to decipher on the ground, but computer analysis helps us to make sense of the records. The autumn migration is leisurely and large – leisurely because the urge to find a territory and mate is no longer present, and large because of the presence of the young of the year.

The period between the spring and autumn peaks is slightly less than five months. One of these months is spent reaching the breeding area, and another in returning. The intervening time is taken up in rearing the young.

More interesting are the figures for record size. The average clutch size in the lapwing is four, and mortality among the young is about fifty per cent, so that, for every two lapwings passing north in spring, roughly four can be expected to pass south in autumn. The computer shows that the autumn migration is indeed virtually twice the size of the spring one, although the picture is complicated by the presence of non-breeding birds and the early arrival of winter visitors.

Migrating lapwings bring with them a sense of adventure, of viatic excitement, and, in the autumn at least, give an overwhelming impression of lassitude. For the adults, the great labour is over for another season. For the young, the vastness of their trek is just becoming apparent. They are like an army in retreat.

In this area, the valley of the Colne is the lapwings’ chief highway. Loose-winged, shabby and moulting, they pitch in straggling flocks, breaking for food and rest in traditional places where they know they have a chance of remaining undisturbed.

There are about a dozen favoured sanctuaries along the valley. Later in the season, large numbers will congregate on the stubble by the main road, within yards of the traffic. Against the sun they are hardly visible: not one driver in a hundred knows they are there.

At this time, though, the birds prefer to keep even closer to water. On the sloping pastures near Hampermill, hidden among the gravel strands and islands at Stocker’s Lake, on the wide lawns at the Maple Cross sewage works, or here beside the glittering water of Moorhall Gravel Pit, they doze with heads on backs, preen, or pick desultorily at a spider, worm, or insect in the turf.

A hundred yards or more of water lie between you and the birds. Seated on the grassy bank of the causeway between Moorhall and the much larger Broadwater at your back, you are studying the flock and trying to count the number of adult and juvenile birds.

There is a class of bird-watchers, called “twitchers”, who seek only to add sightings of rare species to their checklists; ornithology is not a matter of train-spotting, although every bird-watcher is pleased and excited if something unusual comes his way. No: it is a matter of coming to know the birds and their places with an intimacy which allows you to share, if only slightly, in their lives. To know where these lapwings are from and what they are doing here is a pleasure a hundred times more rewarding than adding yet another name to a list.

There is a complacent satisfaction too to be had from living in the same district for a long period of time. Only in this way can you experience the subtler pleasures of bird-watching – such as a true appreciation of this June afternoon at the gravel pits when compared with all the cold, damp, or blustery days of the winter.

The lapwings are spread out along the ragwort-dotted pasture, among a grazing flock of Canada and grey lag geese. Those not feeding look numb with fatigue, torn between the urge to rest and the urge to travel on.

From here their upperparts do not seem black at all, but a bronzy brown. The edges of the wing feathers especially are paler, almost cream-coloured, where they are abraded and worn.

The birds are almost all facing north-east, into the breeze, but, since many of them are feeding and the geese are also moving about, an accurate count as yet has been impossible.

And now it is too late. Two trespassing boys have just ducked through the barbed wire fence. The flock takes wing: black and white now, in wavering formation, there are still too many to count. Perhaps a hundred and twenty.

They turn west, rising against the trees. By now they are above the main road, above the glass and metal and the roar of the traffic, and, with a few scarce, reedy cries of joy, are beyond the old Denham film studios and again on their way south.

(Introduction to these pieces; see all)

Swallows

Image: Beentree

“One swallow does not make a summer”, but tens of thousands do, and now that they are here in force we can safely say that summer, in its broadest sense, has arrived at last.

The swallow is not the first of its family to appear: the sand martin is usually the earliest. The swallow itself is next, and then the house martin. Finally, on or about 23 April, comes the swift – which is of course not a member of the swallow family at all.

The four birds each catch their insect food in flight, and although superficially similar, are not difficult to tell apart. The swift is wholly dark except for a pale patch on the chin, and has very long, scimitar-like wings and a short tail only moderately forked. The three hirundines also have forked tails, but their wings are shorter, and they are all white or whitish below. The sand martin has earth-brown upper-parts, the house martin and swallow dark blue, but the house martin has a distinctive white rump by which it can be told even at a great distance.

It would be hard to think of a more pleasing or attractive bird than the swallow, or of one which adds more charm to the countryside. Its generally low, graceful flight is marvellously smooth and controlled, swooping over a cornfield, endlessly quartering the broad expanses of pasture where sheep or cattle are grazing, by whim turning to left or right when coming to an obstacle, or, inches from the turf, skimming among the boles of standing trees.

The swallow is such an exact and delicate artist of flight that it drinks on the wing, dipping its lower mandible into the surface film of the river to scoop up a little water. When it wishes to bathe, it descends an inch further, douses itself, and then rises to complete its toilet in the air. It rarely settles on the ground, except to collect particles of gravel for its gizzard or materials for its nest, and almost all of its food – mainly gnats, flies, and small beetles – is taken on the wing.

The elegance of the swallow’s flight is matched by the beauty and rightness of its plumage. The dark blue upper parts have a metallic sheen, varying almost to dark green depending on the angle of the light. In the adult male especially, the outer tail feathers are attenuated into streamers which are can be fully two inches longer than the next feathers in. The tail feathers are not blue, but a deep bottle-green, marked on their inner webs with spots of white. Below, the swallow is buff on belly and underwings, with a metallic blue band across the chest and, setting off all the rest of the colours, a dark chestnut throat and face.

The female is normally rather whiter below, with shorter streamers. She and her mate always return, if possible, to the same nest-site year after year. The favourite place is a ledge or rafter in a barn or outhouse, although at one time the deep recesses of large, old-fashioned chimneys were much used.

Before the widespread construction of buildings, the swallow must have been quite a rare bird in England, for its presumed natural nesting sites – caves and sheltered hollows in rock-faces – are few and far between. Since the time of the Romans, it has become completely adapted to using human “caves” for its nests, and is now one of the few species, like the house sparrow, which is more at home with man than in the wilderness.

The nest itself is made of mud, collected from puddles and riverbanks and reinforced with shreds of grass. It in is the shape of half a saucer, and is lined with the softest bents and feathers (the latter often collected in flight).

The eggs, normally 4-6, are white, blotched and speckled with russet and grey, and are incubated mainly or completely by the female. They take a fortnight or so to hatch. Both parents feed the young, which must be a daunting task, bearing in mind the slightness of each catch. This could be one of the reasons why the young take a comparatively long time – about three weeks – to leave the nest. As soon as they can fly and feed themselves, the parents begin another brood, and there may even be a third.

So strong is the urge to depart in the autumn that when, because of bad weather or through some other delay, this third brood is late in the year, the nestlings may be abandoned and left to starve.

For the early naturalists the swallow was the summer visitor which most exercised their curiosity. In one camp were those who believed, as the Greeks had done, that swallows and martins spent the winter either in the mud at the bottom of ponds, or in hibernation in a hollow tree-trunk or cave; in the other were those who believed in migration.

The advent of modern travel and bird-marking with leg rings settled the matter, and now we know that the swallows which nest here winter as far south as the Cape.

There they remain until late February or March, when, covering a hundred miles or more each day, they begin to make their way northwards. Once over England, the swallow migration progresses in a broad front, with a tendency to follow river-valleys where these run in the right direction.

And finally, within a few days on either side of 6 April, the swallows again return and bring their delightful presence to make us yet another summer.

(Introduction to these pieces; see all)

Herons

Image: Karen

The telescope is set up on its tripod and turned to medium power. In the clear circle of light there is a grey, fluffy, and rather comical-looking head, poking above the edge of the nest.

A moment later another head rises behind it, another chick: there are three in all, and they have just become aware of the return of one of their parents. Reducing the magnification, we are just in time to include within the circle the adult heron as it arrives, ruffles and then sleeks its plumage. Zoom in again, to maximum power, and we see the adult bird lean over and open its bill.

All three chicks strain upwards to be fed, but only one is selected, either through the discretion of the parent, sharing the food out equally, or because the chosen chick is more pushy than the others and does not scruple to take the food intended for its fellows.

With a gulping motion the parent bird regurgitates the contents of its crop and passes to the chick a semi-digested mash of fish, with a leavening of frogs, perhaps, or a rat or water-vole – delicious for baby herons and, for the moment, the chief interest of their lives. The parent has spent an hour or two collecting it, at any distance up to twelve miles from the colony, but probably no further away than the adjoining lakes and streams.

Only in recent years have herons begun to nest locally again. Several decades ago there was said to be a small heronry at Charlotte’s Vale, near Grove Mill at Watford, but otherwise the only nest-site was at Marsworth Reservoir, Tring. Then, in the seventies, herons began to take an interest in Broadwater, a large flooded gravel-pit near Denham.

Before excavation took place, the contractors agreed plans to leave a specified number of islands in the lake. The largest group of these, in the southern end, has now become covered with alders, birches, and willows, and provides a sanctuary for a variety of breeding and roosting birds.

For years the herons were to be seen hanging about the islands during the breeding season. Finally, after a number of false starts, some nests were constructed and the colony began. By now there are twenty or more nests to be seen every spring: bulky platforms of sticks, lined with twigs and other bits of vegetation, sometimes built from scratch, but more often based on the previous year’s and enlarged. The female does the building work, while the male provides the materials.

The breeding season begins early, for the heron is a large bird and its young take a long time to grow. The eggs, normally three to five in number, are laid in February or March, and are incubated for about twenty-five days. The young are ready to leave the nest about seven or eight weeks later.

By the end of May or early June, the young herons, wearing the drab grey plumage of the juvenile, have flown the nest. Some remain at Broadwater, loafing about on the islands or shore or perched on the colony trees, but the rest disperse quite widely over the surrounding district.

The colony at Broadwater has proved a great success, and an offshoot has now been established among the wooded islands and gravel strands at Stocker’s Lake, a couple of miles to the north.

As a result, the heron, once noteworthy away from its recognized haunts in the Colne Valley, is now becoming a frequent visitor to many sites where previously it was virtually unknown.

While they show no sign of breeding again at Charlotte’s Vale, the herons have adopted one particular field there as a daytime roost. Here they wait, digesting their food, until darkness falls and it is safe for them to return to the streams and rivers which, during the hours of daylight, are prone to human disturbance.

The field is broad, sloping, and roughly triangular, bounded on one side by Grove Mill Lane, on another by a narrow strip of woodland beside the River Gade, and on the third by more extensive woods adjoining the golf-course. On a high part of the slope is a single large cedar of Lebanon; the herons either perch on its branches, or on the ground elsewhere in the field – often beside the wire fence parallel with the river. As many as fourteen birds congregate here during the day from September to March, although four or five is a more usual number.

By late January most of the breeding birds have already returned to the Colne Valley to stake their territories among the trees and repair the nests in readiness for another generation of young.

Gravel workings such as these at Broadwater are often criticised for the damage they cause to the environment, and certainly much has been lost here – the botanically rich Harefield Moor has been virtually destroyed. None the less, there are compensations, of which the heronry is one of the most interesting and exciting.

On this cloudy afternoon at the end of March, the colony is in full swing, with as many nests occupied out of sight as are in plain view. The air above the trees is full of parent birds coming and going, and it looks as if a bumper crop of chicks is again to be brought off this year.

The first chiffchaff

Image: א

From the wintry thicket of sallows across the river come two silvery notes, in colour like the March sunshine itself, repeated several times in succession, rising and falling in an irregular and unpredictable cadence. The sound, noticed just a moment ago, brings with it a surging feeling of freedom and release, as if a long and tedious series of obstacles had finally been overcome. The first chiffchaff has arrived, so it must be true: spring is here, and that really means that winter has gone at last.

Presently you manage to glimpse the bird, a small, slight warbler with dark legs and a faint eyestripe, the plumage dusky olive above and lighter below. It is flitting about in the branches near the water, tirelessly searching for small spiders and insects, which it takes with a deftness and delicacy almost too quick for the eye to follow.

The song is abandoned; the chiffchaff has become more absorbed in its feeding, and flits now to an elder bush whose oily, dark-green leaves are already well out. The bush holds no interest, and the chiffchaff moves on a few yards to the north, to the red-stemmed dogwood thicket, where it again begins to sing. Chiff-chaff, chiff-chaff, chaff-chiff, chiff-chaff.

But “chiff-chaff” is too harsh a way to represent the song. The Germans call the bird “Zilpzalp”, pronounced “Tsilptsalp”, which comes a bit nearer the truth, though the notes, like nearly all bird sounds, are impossible to render accurately in any human scheme of phonetics. Later in the spring the song will be heard away from the river, in woods and wooded scrub, well-timbered parkland and gardens, but the earliest arrivals nearly always appear by water.

Although one or two chiffchaffs frequently spend the winter along this stretch of the Colne, this bird, with its song and the way it is progressing from bush to bush northwards, is almost certainly a migrant.

The chiffchaff is usually the first in the annual tally of our local summer visitors. A day or so later comes the wheatear – scarcely to be found in this district now, unless sometimes on the broad arable fields above West Hyde; next, the willow warbler, outwardly almost identical to the chiffchaff but with a completely different song; next, the sand martin, tree pipit, and yellow wagtail; and then, in quick succession, the swallow, blackcap, house martin, and all the rest, ending with the turtle dove, normally the last of the common migrants to arrive, in the latter days of April or the first of May.

Most of these birds winter in Africa, some as far south as the Cape. How they manage to navigate is still not properly understood. Some species, the blackcap, for example, have been shown definitely to take their bearings from the stars. All can steer by the sun and have the acute sense of time which this necessitates.

It is believed by some scientists that certain species have an inbuilt compass sensitive to the earth’s magnetic field, though no one has yet found any tissues which might perform such a function. A compass would certainly explain some of the more spectacular feats of bird navigation, in fog or on cloudy nights; but then, these are the very conditions most likely to confuse and disorientate most migrants.

Leaving aside the technical difficulties of nagivation, the main problem for migrants is the sheer expenditure of energy needed to complete the journey. Larger birds, such as eagles and storks, which have wide, high-efficiency wings, are able to climb to altitudes where they can take advantage of the wind. Small ones, though, like the chiffchaff, tend to progress yard by yard on the ground, and this method of travelling is called “bush-to-bush” migration.

Set against all the difficulties and dangers of migration, the advantages to the species are very great. It is able to breed in latitudes which, uninhabitable in winter, have immensely long summer days compared with those nearer the equator. At midsummer in England there can be as many as eighteen hours of daylight in which to find food for the young. This enables more and larger broods to be raised, and the increase in breeding success must outweigh the losses of adult and immature birds on the spring and autumn migrations.

Our chiffchaff this morning has probably wintered no further away than the Mediterranean. Nonetheless it has had to cross the whole of Europe and, worst of all for such a small land-bird, the English Channel. Having made land on the Hampshire, Sussex or Kent coast, it has moved steadily northwards, following wherever possible the river valleys, which are both sheltered and provide the most abundant supply of early insects.

Yesterday or the day before, some combination of landmarks in the broad valley of the Thames near Staines directed it northwards along the Colne. Twenty miles later it appeared here.

Now it has passed on, several hundred yards upstream. The urge to move north and breed is irresistible, of a pattern with the daily increase in the power of the sun.

Having been silent for a while, the bird is heard singing once more, faintly, a new arrival at some fresher and more northerly stretch of the river.

(Introduction to these pieces; see all)

A moorhen

Image: Mehmet Karatay

The spring equinox is only a month away. During the past week or so, the sun has been trying out its strength as if in rehearsal for the season to come. Between showers and periods of cloud, it has lit up the hills and pastures and sent experimental patterns of reflection up into the old willows by the canal.

During these warm interludes the seesaw song of the great tits can be heard most loudly; the rugged bark of the willows seems almost to expand in gratitude. Fraction by fraction the puddles on the towpath are shrinking. The river is no longer so full. The wind is being given a chance to do its work, and, on balance, the countryside is beginning to dry out. Winter, with all its rigours and privations, is nearly over at last.

There have been many casualties among the small and weak, and especially among those animals which are deprived of their food by ice. Quite early on in the snowy weather the kingfishers went elsewhere. Some have perished. The water rails also fared badly, but their larger relatives, the moorhens, for the most part stayed and stuck it out.

Even in one horizontal blizzard, when the sheer density of driving snow obscured the wood on the hill, the moorhens were to be seen among the stubbles, searching for whatever they could find to keep themselves alive. They endured night after night of freezing fog, sleet, granite-hard frost. They survived the attentions of foxes which were themselves driven to desperation by hunger and cold. Each morning the moorhens’ tracks – large, backwards-pointing arrows in the snow – could be seen crossing and recrossing the riverbank and the towpath and the lawns adjoining the water.

Now all that is forgotten. What lies ahead is spring, summer, the breeding season, the time of plenty. In April and May there will be the satisfaction and damp warmth of a deep nest filled with eggs, hidden somewhere safe and silent among the flags. Afterwards there will be the chicks, like small black powder puffs with beaks, frantically swimming behind their parents and trying to keep up.

There is one moorhen, though, which, if you are not careful, will not even live to see tomorrow, still less the breeding season. It is caught up in the middle of a thorn bush beside the towpath. Had a slight fluttering of dark feathers not attracted your attention you would have gone breezing past.

The thorns are sharp and tear at your wrist where it is not protected by the glove. The moorhen thinks you are going to kill it. Terrified, it tries in vain to burrow more deeply into the tangle of branches, but its movements are hampered anyway; a few moments more and you make contact. Holding the bird as gently as you can, and moving branches aside with your free hand, you slowly and carefully begin to bring it out.

Your fears are confirmed as the moorhen comes free of the thorns and you are able to examine it more closely. The wings and legs have been snared by several yards of discarded fishing line. The bird’s struggling attempts to get free have made matters worse: the thin, translucent filament is wound into an inextricable maze of knots and tight loops, some so tight that the flesh on the upper legs has been deeply cut. Each movement of the bird tends to widen the wounds.

The moorhen makes no sound. Its beak is slightly open and its small, button-like eye seems no longer to register fear, but resignation. It is waiting to be dispatched, in accordance with the law. Big eats small. That it understands. But it cannot understand why or how it became ensnared. Nothing in its ancestry or experience has prepared it for nylon line.

Using fingernails alone, you would never be able to get the knots undone. They are simply too tight, too small, and too complicated. A penknife would not help; even a fine pair of scissors would be too clumsy. Luckily, since having seen a dead thrush trussed in this stuff and dangling from a tree, you now always carry a very thin, sickle-shaped scalpel blade. It is brand new, and gleams through a smear of grease as you take it from its cardboard sleeve.

Sharp as the blade is, the job is difficult and takes a long time. The moorhen slowly becomes more placid, sensing perhaps that it is not to be killed after all. One wing comes free, and then the other. Being especially careful, cutting one strand at a time, you free the legs. At last the final bit of filament is removed.

Unnoticed, the sun has gone in again. None the less there can be no doubt about it: spring is on the way, and for the moorhen now as well.

Its wounds will heal quite quickly. Birds are hardy and resistant; there are no fears on that score. It is already able to walk unaided. As you stand clear, it slightly stretches its wings. After a moment’s further trial, the moorhen launches itself and takes off and, legs dangling, flies across the ditch, beyond the nettles, and disappears from view.

(Introduction to these pieces; see all)

Bird Song

Unless you are lucky enough to have a knowledgeable friend with the patience to teach you, learning to identify birds’ songs and calls can be a difficult business. There are records and cassettes available, and these are certainly a help, but there is no substitute for learning from nature.

It is well worth the trouble. Most experienced ornithologists use their ears just as much as their eyes and, once learned, the different birds’ voices are found to be quite distinctive after all.

Early in a new year is an excellent time to start. At present, very few species are in song, and those that are can be identified with ease. As the year advances, other species begin to sing and can be learned one by one, well before the arrival of the summer visitors. Once the voices of the resident, native birds are known, it becomes much easier to learn the songs and calls of the summer birds which make a May hedgerow such a confusing place for the would-be ornithologist.

If you have a garden or just live within earshot of singing birds, or if you regularly walk the same route to school or work, the problem is simplified still more.

Take a sheet of foolscap or A4 paper and divide it into 15 or so columns and as many rows as you conveniently can (squared paper is ideal for this). Each row represents a day; in each of the columns, write the name of a bird as you identify it or as it comes into song.

Keep your chart and a pencil in a handy place, and each evening make a mark in the columns of those species that you have heard singing during the day. This exercise, if carried through, will have the effect of making you listen and differentiate every single day, so that learning becomes as effortless as possible. You will also end up with a scientific record of the way that the number of species singing gradually increases as the summer approaches.

The first candidate for a column is likely to be the starling, which sings virtually throughout the whole year. Its song is often delivered from a chimneypot or bare twig at roof height, and consists of an unmusical collection of wheezes, rattles, and whistles, incorporating a number of sound-effects and impressions of other birds. The starlings near our house do a very passable curlew, quite a good coot, and a fair lapwing impersonation. According to one newspaper report, an amateur football match once had to be called off because of a starling which insisted on copying the sound of the referee’s whistle.

Another bird in song throughout December and January is the dunnock, or hedge sparrow, a modest, inoffensive little creature, brown above and grey below, which moves about the edges of the lawn with shuffling movements of its wings. The song is a pleasant warbling, rather subdued, of no great duration or power, slightly discordant, repeated at short and irregular intervals. It is usually given from a shrub or low bush; the main call-note, worth learning because the bird spends so much time hidden, is a piercing tseep.

The starling and the dunnock sing almost continuously during January, whatever the temperature. On milder days they will be joined by the robin, song thrush, and perhaps wood pigeon.

In winter, both male and female robins maintain an independent feeding territory, and both sexes sing. This winter song is often described as thinner and more wistful than the males’ spring song: it is made up of short warbling phrases, slightly shrill. Sometimes, if the weather is specially mild, a robin can be heard in January and February at night. The alarm call is a distinctive tic, tic; other calls are a plaintive tsee, tsit, and variants.

The song thrush is one of the virtuosi of the garden. Its song is clear and musical, consisting of a succession of short phrases. Each phrase may be repeated several times, and it is this repetition that is so typical of the song thrush. Some thrushes are more accomplished singers than others, and day after day can be heard going through and refining a repertoire that can include half a dozen favourite phrases. The alarm call is a sudden tchik-tchik-tchik. A note often given in flight is sipp, and the distress call is a penetrating seee.

The most beautiful song of all comes from the blackbird, which does not start to sing regularly until the end of February. The blackbird’s voice is richer and more mellow than that of the thrush. The song is more sustained; there is no straight repetition, but an endless improvisation and exploration of a number of themes. It has been found that individual blackbirds vary a great deal in their talent. The song of young birds is rather uninspired, but an older and more experienced male can give a truly musical performance. Such a bird will sing even though there is no need to guard the territory, and on such occasions it is hard not to believe that one is listening to a real aesthetic sensibility at work.

The blackbird’s alarm call is a characteristic loud chatter. A note of milder alarm is chook; and at dusk, just before going to roost, the neighbourhood blackbirds engage in a communal chorus of chik-chik-chik-chikking.

The only songbird which might be confused with the song thrush or blackbird is their larger relative, the mistle thrush, which is less common and is generally found in wilder countryside. It begins to sing regularly from the second week of February. The song is loud, relatively unmusical, with an aggressive quality, consisting of a series of short phrases delivered from the topmost branches of a tree. The alarm note is a harsh churring rattle.

Other birds to listen out for, in order, are the collared dove; the wren, whose song is astonishingly loud for the size of the bird; the chaffinch, greenfinch, blue tit, great tit, and, if you have large old conifers nearby, coal tit and goldcrest.

By the time March comes round and with it the first chiffchaff, you should be in a good position to learn the voices of the summer birds. The greatest challenge to your skill will be the dawn chorus in mixed woodland, but, until then, good listening!

(Introduction to these pieces; see all)

Open All Hours

However hard the weather may be, the springs feeding the old watercress beds always continue to flow. They rise from a depth that is beyond reach of the frost, and on a cold day the water, which is limpid and sweet, feels almost warm to the touch. It flows across a mud and gravel bottom, making a stream that is here broad and there narrow, occasionally becoming louder as it drops an inch or two from one bed into the next.

Years ago, when these beds were worked commercially, the stream was controlled by a system of sluices and gates. Like the men who worked them, the sluices have gone now, rotted away, and the stream has to find its own passage through the sedges and willowherb. The cress then was eaten in local salads or decorated more expensive dishes in the West End; now it remains where it is, and makes an unpolluted home for a rich and abundant population of small aquatic invertebrates – worms, insect larvae, and the rest.

They are the set lunch for certain birds that may be found at cress beds more often than in most other places of the district. The beds here in the Gade Valley, as well as along the Colne and the Chess, form an important winter habitat for ducks and waders, and for wagtails and pipits – including the water pipit, once thought to be very rare but now known to be a regular visitor to watercress beds throughout the country. This discovery was made locally by a local bird-watcher to whom these abandoned ditches at Watford, between Bellmount Wood Avenue and the canal, are well known.

Quite often a few snipe are to be found here. If disturbed, they will fly up with a soft yet rasping cry, and pitch again after circling in a towering spiral that may take them two or three hundred yards further along the ditches. As might be expected of a gamebird, the snipe is extremely wary and unapproachable; but, if seen close to, it is revealed as a slender, thrush-sized bird beautifully camouflaged with brown and darker brown. The lower breast and vent are pure white; the legs are green; and the bill, which is inordinately long and equipped with a sensitive and slightly bulbous tip, is worked with a sewing-machine action in the mud.

The common snipe is usually silent as it feeds. Its smaller and scarcer relative, the jack snipe, however, progresses through the shallows with a series of inward and absent-minded grunts, as I once learned when I was lucky enough to observe one from a range of only six feet.

I was thirteen then, concealed in a cramped hide, made from bits of scrap wood and bundles of dry willowherb, which a like-minded school friend and I had constructed beside one of the ditches. From the same spot we watched most of the birds of the ditches in intimate detail. Besides the common sorts that came down to drink or bathe or look for insects, and besides the moorhens that may be found by almost any scrap of water, there were water rails – like smaller, drabber moorhens with a longer bill – and during several memorable dusks, up to four even smaller and drabber rails called spotted crakes – unusual birds indeed.

At that time there were three ditches, instead of the one that remains. They were separated by a tangle of reeds and scrub that held breeding pheasants, whitethroats, and sedge warblers, and in winter a large pied wagtail roost. From November to March the ditches would often produce a green sandpiper or two, besides other, scarcer, waders, a good number of mallard, and ten or twenty teal.

All that has now gone, buried under the sterile expanse of some rugby pitches which hardly ever seem to be used. Too late the site was declared a nature reserve; the bulldozers have driven the best of the birds elsewhere.

A few of them may be found a mile or two downstream, at the cress beds lying between the canal and Cassio Lake. A public footpath runs along one end, beside a rickety corrugated iron fence which helps to conceal your presence.

Here, if you are quiet and prepared to wait, you have a very good chance of seeing kingfishers, herons, water rails, snipe, grey wagtails, and, a speciality of these beds, teal. During the recent cold snap there were upwards of fifty teal feeding busily among the cress near the fence, giving marvellous views.

They had homed in from icebound ponds and streams up and down the valley and beyond. Like the snipe, the moorhens and mallard, and all the other birds, they rely on the warmth of the springs for their emergency supplies of food. The cress beds, at least, always remain open for customers, no matter how low the mercury falls.

(Introduction to these pieces; see all)

Secrets of the Goldeneye

Out there, towards the centre of the sheet, is a drake goldeneye, accompanied by three females. They are diving repeatedly, actively feeding. As he emerges the drake looks brilliant in the January sunshine, an essay in black and white.

Of all the species of wildfowl which come to spend the winter with us, the goldeneye is one of the most striking and distinctive. The plumage of the drake is not really black and white, but snowy white and the darkest glossy green or purple, depending on the angle of the sun.

At this range, though, the head looks black, with a large white spot below and just in front of the eye. This, and the elegant black and white pattern on the back and wings, lets you identify him at a great distance out on the water, even when your binoculars are being jostled by an east wind which numbs gloved fingers and makes the eyes stream.

The forehead of the goldeneye has a characteristically steep profile which enables you to pick out the females and immature birds – with drab grey bodies and chocolate brown heads – from the coots, pochards, and tufted ducks.

As would be expected, these drabber birds, or “morillons”, usually outnumber the males. At its height in midwinter, the local population consists of no more than about a dozen birds, if that.

Looking back over twenty years of records on index cards, the assorted localities, numbers, and dates make for confusing reading. An evening with a pocket calculator and a tablet of graph paper is scarcely more enlightening. Statistical analysis, the calculation of means and probabilities and standard deviation, is time-consuming and prone to error.

But the naturalist now has a new ally: the microcomputer. Even a relatively humble model, obtainable in any high street, makes short work of the statistics. With a carefully designed program and carefully entered data, the real wizardry of the computer takes over and magic begins to emerge.

The records, hundreds of them laboriously culled over many notebooks and many winters, are transformed into a volatile set of electronic signals which the program manipulates at incredible speed. In a few moments we can abstract any given group of records – for locality, date, number, sex ratio – or put them back, or give them special weighting for greater observer coverage, or less. Touch a key and the graph illuminates the screen. Touch another and the figures appear.

January is shown to be the peak month for goldeneye in the Colne Valley between Rickmansworth and Uxbridge. Total birds and average record size both reach their maximum – except at Stocker’s Lake, where there is a unique and unexpected fall. Why, and where do the birds go?

Press another few keys. Yes: that’s where they go. A little way down the valley to the giant Broadwater gravel pit at Denham. The graph here shows a sudden and untypical rise in January. Press more keys. The rise at Broadwater corresponds almost exactly to the fall at Stocker’s Lake. But why?

The answer probably has something to do with the goldeneyes’ food: the molluscs and crustacea they find in the mud on the lake floor.

Either there is a preferred prey animal at Stocker’s Lake which is harder for them to find in January, or some special delicacy at Broadwater which becomes numerous in that month. Or else it is a simple matter of ice cover. Broadwater, being so much bigger, will be slower to freeze and will do so less often. Already the computer is beginning to suggest lines of approach to the problem: it wants more data, on the weather, on water temperatures, on the goldeneyes’ diet.

The machine reveals things previously known only to the goldeneyes themselves. Hidden deep in the figures are trends and patterns which a lifetime of casual observation would never uncover. They are real and constant from year to year, and must somehow be of service to the species in its struggle for survival. Similar, but slightly different, patterns emerge for closely related species. As the relationship grows more distant, so the patterns become more dissimilar. Goldeneye resembles teal, because both are ducks; but teal resembles mallard more, because teal and mallard are very near in evolutionary terms and have much the same way of life.

Here by the shore at Broadwater, despite your thick coat and woollens, you begin to shiver. The wind is dashing real waves, bigger than many at the seaside, against the crumbling soil of the bank. The goldeneye are impervious to the waves, impervious to the cold. Look – the drake has just surfaced.

How are his preferences and tastes programmed in the living chip behind that high, triangular forehead? And where in his memory are the myriad bits of navigational data that will guide him and his followers home in spring, a thousand miles and more to the rivers and forests of Russia and Scandinavia? Over what aeons of time was that machine code written?

A mystery. It’s all a mystery. There: he has dived again.

(Introduction to these pieces; see all)

Ancient Aviators

The cormorants have chosen this lake, the biggest gravel pit in the Colne Valley, for their roosting place. There is a group of islands in the southern end which they have made their own. The birch trees there are sickly and dying, frosted with droppings. On these short winter afternoons, upwards of a hundred and twenty birds may be seen perching there, high and low, clustered in the trees like so many huge black fruits.

Today, for the first time all week, the sky is blue. Far off to the south and east, beyond Hillingdon and Ealing, the brown breath of London rises as smog; but northwards along the valley, beyond Rickmansworth and away to the west, the horizon looks comparatively clear. Here at Harefield there is as yet little of man in the atmosphere, except for the light planes constantly circling and landing at Denham aerodrome.

Since the wind comes generally from the west, the aeroplanes usually head straight across the valley and over the lake. They fly so low that you can see into the cockpits. Once over the main road, wings wavering somewhat if the pilot is a pupil, and with the undercarriage barely seeming to clear the trees, each one then drops abruptly and vanishes behind the ridge.

When they disappear like that you are half afraid, having seen too many cheap films, that after a short delay you will hear a low-budget explosion and see a low-budget pall of smoke. But no. Disaster is always held, once more, at bay.

No mechanics service the cormorants which use the lake. Neither do the birds bother with pilots’ licences or subscriptions to the flying club. They have no need of manuals or airworthiness regulations. In flight they are perfect.

The style is basic rather than graceful, but beautiful none the less. It gets them very efficiently from one feeding area to the next, lets them escape from enemies, and allows them to perch and rest on any projection that takes their fancy.

The feet are broad and webbed; the dark skin and toes look rather clumsy wrapped round a stub of branch, but the bird appears quite comfortable and will remain there for a long time, perhaps with wings opened, slowly digesting its last gluttonous meal. The plumage is oily and dark, and the head has a peculiarly reptilian slant. It is easy to remember that the cormorant is a relatively primitive bird. Archaeopteryx might have looked out on the world through such an eye as that.

The earliest specimen of the cormorant tribe yet found in Britain turned up in Hampshire, a fossil some fifty million years old. Even at that time the technical problems of making a cormorant fly had been completely solved, the complex equations of lift, thrust, and drag neatly dealt with and given tangible form in the bird’s shape and plumage. The wingbeats that pass over the gravel works, over the pylons and the arterial road are the very same that passed over Eocene lakes and estuaries, over a Hampshire that would seem as strange to us today as the farthest comer of Brazil. In another fifty million years there will probably be similar-looking birds, perhaps even in this very spot, digesting fish and drying their wings on a planet where mankind and all its works are preserved, if at all, as fossils.

The cormorants care nothing for their illustrious ancestry. They care only about the next cropful of fish.

A bird at the end of the island planes down to the water. Swimming low, its back awash, it dives with a pouncing leap. Underwater, where we cannot see it, the most important form of locomotion is brought into play. The cormorant is said to pursue fish with the feet alone, without using the wings except occasionally as brakes. It can dive to a great depth, staying submerged for as long as seventy-one seconds, but prefers to surface to swallow its prey.

And there it is. It has come up a few yards farther out, clutching what looks like a roach. The head is tipped back; the jaws open, and down the fish goes. The neck bulges for a moment, and then, its appetite whetted, the cormorant dives for more.

(Introduction to these pieces; see all)