Birds’ Eggs – Natural histories of extraordinary species that changed our world


Birds’ Eggs – Natural histories of extraordinary species that changed our world

Mysterious Fragility

Like many other boys obsessed with nature back in the 1960s, Brett remembers the thrill of watching a blackbird fly back to its nest, then hearing the soft ‘chuck’ of the hen bird as she departed in a flurry of wings. There in the tightly woven nest lay a quartet of irresistible sea-green eggs, heavily freckled in reddish-brown. The act of breaching the sanctity of the nest was fraught with guilt: it was hard not to imagine the heavy hand of the local policeman falling on his shoulders as he reached to take an egg. But the possibility of being caught red-handed was part of the attraction. There was an unwritten code among schoolboys that only one egg should be taken from each nest: the removal of a full clutch could lead to temporary social exclusion from the informal collectors’ club.

Once collected, the trophy was blown by piercing a hole in one end and expelling the yolk through a straw, then mounted on cotton wool in a small cardboard box. After a few days of covetousness, this egg was stored away and forgotten, a fragile reminder of one passion soon to be eclipsed by others, much longer lasting.

But for some, the lure of egg collecting lingered well into adulthood. These characters once had their own group, known as the Oological Club. Its activities were frowned upon by many members of their parent organisation, the British Ornithologists’ Union, which in 1908 had passed a resolution condemning the taking of birds and their eggs. In the Spectator of 11 August 1922 correspondence appeared under the title ‘The Eggs of British Wild Birds and the Collector’, referring to the large numbers of wild birds’ eggs exhibited at one of the club’s regular dinners:

It is made clear that most of the eggs – of the Red-backed Shrike and the Fly-catchers – had been collected over a long period, and that both the Oological Club and the British Ornithologists’ Union, of which the Club forms a part, strongly deprecate the action of any member who disregards the Acts for the protection of wild birds.

And in the Illustrated London News, William Plane Pycraft of the Natural History Museum commented:

If the whole science of oology is not to be brought into disrepute, these all-devouring schemes must be abandoned. They are intemperate and exasperating. They can only be carried on by flagrant breaches of the law, often possible only by the exercise of a low cunning disgusting to all reasonable men. That the collecting of birds’ eggs is an essential part of the study of ornithology is beyond dispute. But the collector must exercise discrimination.

It wasn’t until the passing of the Protection of Birds Act in 1954 that it became illegal to take the eggs of most British breeding birds. The same year saw the publication of the Observer’s Book of Birds’ Eggs, a pocket bible that went on to sell 1½ million copies. Its itchy-fingered readers were meant to gaze fondly, but not to touch. As it happened the Act didn’t specifically outlaw taking the eggs of common wild birds, and schoolboys’ clutches remained safe from those of bobbies on the beat, until the Wildlife and Countryside Act finally closed that legal loophole in 1981.

Even so, a hard core of pernicious collectors remains, obsessed with the natural variety in birds’ eggs – not just between blackbirds and song thrushes, but even within the same species, for patterns can vary enormously from bird to bird and from year to year. Their determination to collect as many clutches as possible, and in particular of birds that nest only occasionally in Britain, still threatens the existence of very rare species. So when red-backed shrikes bred in Devon recently, the Royal Society for the Protection of Birds (RSPB) had to mount twenty-four-hour surveillance to protect the nest from egg thieves. Had anyone succeeded, theirs would have been a hollow victory, like stealing a Van Gogh or a Picasso, objects with provenance so notorious that the spoils can only be gloated over in private.

Sadly, these illegal egg collectors do a huge disservice to legitimate scientists, whose analysis of the variation in colour and shape of eggs, and their weight, helps them to study the way clutches and individual eggs vary from bird to bird within a species, and between different, though related, species. This is essential if we are to continue to learn more about the evolution of birds.

Pleasing to hold, beautiful to the eye, versatile in cooking, intriguing in nature, and wonderfully practical – eggs will always inspire us. Yet they are far more, of course, than scientific curiosities or collector’s items. For every one of the world’s 10,500 or so species of bird, from the bee hummingbird to the ostrich, eggs are their way of creating the next generation. Eggs are not, like feathers, unique to birds – fish, reptiles, invertebrates and two species of mammal (the duck-billed platypus and echidna) lay different kinds of eggs too – but few other creatures are so closely associated with this form of reproduction.

A bird’s egg is a miracle of nature. Eggs have been described as ‘a life-support system for the embryo’, protecting it throughout its early developmental stage from a tiny, fertilised ovum until the chick finally hatches out from the shell. And as such, it contains within its hard outer casing everything the developing bird could possibly need to grow and develop, including fats and proteins in the yolk, to feed the developing embryo. The yolk and embryo are surrounded – and protected – by the white, or albumen, which acts as a shock absorber; and outside this, the hard shell.

For us, eggs serve two other crucial purposes: filling our stomachs and inspiring our souls. From the point of view of consumption, it is hard to imagine a world without a readily available supply of eggs. The egg is in some ways the perfect package: the yolk and white contain essential protein; it can be cooked and eaten in many different ways, used in recipes as varied as chocolate mousse, pastry and fried chicken; and its versatility and availability have made eggs from many different bird species a favoured food across the globe – ever since our prehistoric ancestors first stumbled across a bird’s nest, and wondered if those strange ovoid objects might be good to eat.

Today, domestic chickens Gallus gallus, farmed for their meat and eggs, are by far the commonest bird in the world; indeed with an estimated population of around 25 billion, there are almost four times as many chickens as there are human beings. Of these, somewhere between 4.9 and 6.4 billion hens lay an estimated 62 million tonnes of eggs each year – roughly 1.2 trillion eggs, or 180 eggs for every man, woman and child in the world, though of course consumption of eggs varies considerably between individuals and especially between different cultures.

The original ‘chicken’ is a colourful and shy member of the pheasant family living in the jungles of Asia, from India and Nepal to south China, Thailand, Vietnam and Borneo. In the wild, the red junglefowl Gallus gallus is a fairly common and widespread bird, though with its golden-brown plumage, blue-green tail and red wattles just like a domestic cockerel it does look rather out of place in a dense forest habitat or wandering along the side of a dirt track.

Archaeologists suspect that the red junglefowl was originally domesticated not for food, but for sport: ‘cock-fighting’, a cruel but dramatic contest in which males use the sharp spurs on the back of their legs to attack – and often kill – their rival. However, once it was discovered that the hens were prolific layers, something encouraged and developed through selective breeding, the chicken soon became even more popular and widely kept.

When early chickens were domesticated is subject to debate, with some suggesting that it first occurred in southern China as early as 6000 BC (about the time that Britain became an island). They were certainly being kept in the Indus Valley (present-day Pakistan) in 2500 BC, and may have reached south-east Europe even earlier. Traders such as the Phoenicians took the chicken with them throughout the empires of the ancient world, and eventually they spread through Africa and the Americas.

One distinctive breed found in South America, the araucana from southern Chile, lays bluish eggs – a trait it shares with some Asian chickens. This has led to speculation that these chickens did not come to the Americas with Columbus and the European explorers of the late Middle Ages, but much earlier, brought from Asia by the Polynesians, across the vast Pacific Ocean.

Being large and tasty, and with a reliable and regular daily supply, domestic chicken eggs rapidly displaced many of the wild alternatives, though eggs from other bird species are still widely eaten throughout the world. These range from other domesticated birds such as ducks and geese, through to the harvesting of eggs from wild birds including seabirds such as gulls and puffins, gamebirds including pheasants, quails and guineafowls, and in Britain – at least until the introduction of the first comprehensive bird protection acts in the 1950s – ‘plover’s eggs’, from lapwings. The latter featured in Evelyn Waugh’s 1945 novel Brideshead Revisited, in which they became shorthand for the louche sophistication and privilege of young Lord Sebastian Flyte, as he consumes them in his rooms at Oxford, announcing: ‘Mummy sends them from Brideshead. They always lay early for her.’

Once eggs had satisfied their appetites, our ancestors began to regard them in a less utilitarian way, turning to more spiritual, religious and cultural matters. Many ancient beliefs have tended to die away as the modern world becomes more and more sophisticated and far removed from our humble origins, but one particular aspect of eggs is still very much at the forefront of our annual calendar.

Easter eggs, whose origins embrace both Christian and pre-Christian cultures, are big business: about 90 million large chocolate eggs are sold in the UK each year: roughly nine per child.

The chocolate Easter egg tradition is a relatively recent development, originating in France and Germany in the early nineteenth century, and only coming to Britain via Fry’s of Bristol in 1873. But eggs have been associated with the Christian festival of Easter (whose name derives from the pagan goddess of the dawn, Eostre) since the earliest days of the Church. The festival is linked both with pagan rites of spring and the resurrection of Christ, and so the egg – which represents both rebirth and transformation – is the perfect symbol for this twin celebration. However, the use of the egg as a symbol of life predates Christianity by a long way. Hindus believe that the world developed from an egg, while some of the earliest examples of primitive art ever found are on eggs; ostrich eggs decorated with engravings dating back 60,000 years have been discovered at Diepkloof, an archaeological site near Johannesburg in South Africa.

One plausible theory for the origin of the custom of decorating chicken’s eggs at Eastertime (the original ‘Easter eggs’) is that each spring coincided with a glut of eggs, allowing some to be spared for decorating. In addition, there would be a surplus of eggs available because from the fourth century onwards the Church banned their consumption during the forty days of Lent.

These early Easter eggs would have been decorated using natural dyes such as brown from onion skins, black from charcoal, yellow, pink and violet from various flowers, and green from leaves. In some cultures, such as the Ukrainian tradition known as ‘pysanka’, these colours are symbolic: yellow for the sun and harvest, blue for the skies and good health, white for purity, green for new life in the spring, and red for the blood of Christ.

Decorated Easter eggs became especially popular during the Middle Ages: the household accounts of King Edward I for the nineteenth year of his reign, 1290, show that 450 eggs were purchased at a cost of 18 pence (7.5p, equivalent to roughly £55 today), which were then decorated with gold leaf and given as gifts for Easter. This custom had the backing of the Church, as in this traditional blessing: ‘Lord, let the grace of your blessing come upon these eggs, that they may be healthful food for your faithful who eat them in thanksgiving for the resurrection of our Lord Jesus Christ, who lives and reigns with you for ever and ever.’

The link between eggs and the resurrection gains further strength when allied to the belief that the egg represents the stone that closed Jesus’s tomb and was found rolled aside on the third day after his burial – a reminder to the faithful that Jesus rose from the grave.

This belief led to another Easter tradition. Egg-rolling – pushing decorated eggs down steep hills and then chasing them to the bottom – remains popular in parts of northern England and Scotland, while Easter egg hunts for children are still widespread throughout the United Kingdom and North America. Even the sixteenth-century German reformer Martin Luther is known to have held Easter egg hunts.

But when it comes to decorating eggs, one name reigns supreme: Fabergé. Peter Carl Fabergé was a Russian jeweller who in 1885 was commissioned by Tsar Alexander III to make an elaborately jewelled egg as an Easter gift for his wife, the Tsarina Maria Fyodorovna. Fabergé made a beautiful golden egg within another gold and white enamel egg, with a golden chicken and replica of the imperial crown at its centre. The delighted Tsarina commissioned similar eggs every Easter, a tradition continued by her son Nicholas II. However the custom came to an abrupt end – along with the rule of the tsars – with the outbreak of the Russian Revolution in 1917.

Of the original fifty made, roughly forty eggs have survived – so unsurprisingly they are highly sought after. One egg, given by Alexander III to his wife for Easter 1887, had been assumed lost, having last been recorded in 1922. A tantalising hope that it had survived surfaced in 2011, when researchers discovered a picture of what appeared to be the vanished egg in an auction catalogue from 1964. Enquiries revealed that it had been sold for less than £1,000 to a woman who had later died, and that the whereabouts of the precious object was no longer known.

Then, in 2012, a scrap-metal dealer in the American Midwest was idly wondering about the provenance of the ornamental egg he had bought a few years earlier, intending to sell it for its scrap value. Googling the name ‘Vacheron Constantin’, which he found etched on a timepiece inside the egg, he was astonished to discover that this might be the long-lost Fabergé egg. He contacted London jeweller Kieran McCarthy, a Fabergé expert, who flew over to the US to examine the find. On realising that it was indeed the lost egg, McCarthy said: ‘I was flabbergasted – it was like being Indiana Jones and finding the Lost Ark.’ At auction in 2014 the egg sold for £20 million – a record for a Fabergé egg – so far, at least.

The tradition of using eggs in art goes back long before Fabergé. But the most important use of eggs for artists was not as an object to decorate, or even as one to portray in their works, but as a medium for creating the artwork itself. Egg tempera – coloured pigment mixed with egg yolks and other ingredients such as vinegar or white wine – has been widely used by artists since at least the time of the birth of Christ, and probably earlier, as a convenient, flexible and fast-drying medium for painting.

During the medieval and early Renaissance period, up until about 1500, egg tempera (painted on to wooden boards) was the primary medium with which artists such as Giotto, Fra Angelico and Botticelli created their stunning works of religious art. As well as being flexible and ideal for making precise brushstrokes, and producing a smooth, matt finish when dry, egg tempera has one added advantage for posterity: unlike the oil paints that superseded it from the early sixteenth century onwards, which have faded and darkened over time, tempera has managed to retain its bright, vivid colours for centuries.

But perhaps the most unexpected use of eggs in art is found in an unusual tradition practised by clowns. This dates back to just after the Second World War, when London’s International Circus Clowns Club (now known as Clowns International) began employing an oddly practical method to record its members’ make-up: they copied each design on to an egg – or ‘amazing boneless chicken’, which was then placed in a registry that effectively trademarked the identity of each member. Painted on real eggshells, with the inside emptied out, by Stan Bult, the first head of the Circus Clowns Club, these studies now form part of the Clowns’ Gallery and Museum in north London. Though not an official registry, the collection is meant to preserve the uniqueness of each clown’s face make-up. The Department of Clown Registry information sheet explains that ‘it is an unwritten law among clowns that one must never copy the face of another’. In 1984 the new chairman of Clowns International, ‘Clown Bluey’, resurrected it, but instead of using (breakable) chicken’s eggs, decided to employ a professional artist to paint the patterns on to china eggs, as a permanent copyright register of each clown’s unique face. Today the collection – numbering 300 eggs in all – is on display at Gerry Cottle’s Clown Museum, at Wookey Hole in Somerset. The custom has since spread to the United States, where the registry now contains more than 700 (goose) eggs.

On 27 September 1962 a modest book was published in the United States: one that would go on to change the course of history. It opened with an apocalyptic warning: ‘It was a spring without voices. On the mornings that had once throbbed with the dawn chorus of robins, catbirds, doves, jays, wrens, and scores of other bird voices there was now no sound; only silence lay over the fields and woods and marsh.’ The title of the book was Silent Spring; its author, a US scientist called Rachel Carson.

At the centre of Carson’s book was her belief that chemical pesticides such as DDT, then widely used in the agricultural industries of both North America and Europe, were killing millions of birds; hence the dramatic title of her book. For some – such as the smaller songbirds she mentions in the opening lines of the book – death came rapidly; they were poisoned by ingesting the chemical as they fed on seeds or insects in fields sprayed liberally with DDT. But in larger species the effects were slower and more insidious: it accumulated in their bodies as they fed on smaller birds, becoming more concentrated the higher up the food chain it went.

This made birds of prey, especially eagles, sparrowhawks and peregrines – sitting at the very top of the pyramid – uniquely vulnerable, especially because they live for a long time. But although some were poisoned directly, for most the effect of DDT revealed itself in something no scientist could have predicted: the thinning of their eggshells, caused by a lack of calcium. Thinner eggshells were obviously more vulnerable as the birds incubated. As a result, the populations of species such as the peregrine and sparrowhawk went into freefall.

Carson’s claims caused outrage among the chemical and agricultural industries, for which the use of DDT, and other associated chemicals, was producing higher yields and far less loss to pests. Attempts were made to discredit her and her associates; but for the scientific community, who had already suspected that DDT might be to blame for the unusual phenomenon of eggshell thinning, Silent Spring fired the starting gun on new and crucial research to prove or disprove Carson’s theory.

Within six years, two scientific papers had confirmed that DDT was indeed responsible. The first, ‘Decrease in Eggshell Weight in Certain Birds of Prey’, was published in the scientific journal Nature in July 1967. Written by Derek Ratcliffe, a researcher at the Nature Conservancy (now Natural England), it showed that the incidence of broken eggs in the nests of three key species – golden eagles, peregrines and sparrowhawks – had increased hugely since 1950, with peregrine and sparrowhawk eggshells collected after that date weighing on average between one-fifth and one-quarter less than those collected before, due to having thinner shells. He investigated the possibility that this might be due to some other environmental cause such as lack of food or radiation, but concluded that pesticides were in fact to blame.

A year later, in October 1968, the US journal Science published a paper that confirmed Ratcliffe’s sensational findings. Its authors, Daniel Anderson and Joseph Hickey from the University of Wisconsin, concluded that: ‘Catastrophic declines of three raptorial species [peregrine, bald eagle and osprey] in the United States have been accompanied by decreases in eggshell thickness that began in 1947, and have amounted to 19 per cent or more, and were identical to phenomena found in Britain.’

Gradually the theory that DDT was causing these problems for birds gained widespread acceptance, and in 1972 the chemical was finally banned in the United States; though it took another decade, until the early 1980s, for a similar ban to come into force in the UK. Since then, there has been a spectacular increase in the populations of these iconic raptors, and birds such as the peregrine have now colonised major cities on both sides of the Atlantic, including London and New York.

Back at London’s Natural History Museum, twenty-two objects have been specially selected from more than 7 million in the museum’s collection, to feature in a permanent exhibition aptly entitled Treasures. Alongside the first edition of Darwin’s Origin of Species, a fossilised Archaeopteryx – probably the world’s first bird – a stuffed great auk, a moon rock and two objects that feature elsewhere in this book – the Barbary lion skull and the Wold Cottage Meteorite – is a rather more modest exhibit: a large, pear-shaped egg measuring about 13 centimetres across, with a rectangular hole on one side. It belongs to an emperor penguin, the largest and most spectacular of the world’s twenty or so species.

The hole in the egg was made by its finders in order to extract the embryo, which, it was hoped, would show an intermediate stage between birds and reptiles. This turned out to be a theoretical dead-end; and yet, as Phil Rainbow, former Head of Life Sciences at the museum, points out, the cultural significance of the egg has proved far greater than its biological one: ‘We now consider it to be an icon of human endeavour in the name and pursuit of science.’

In an era when we can travel in ease and comfort to most parts of the world, it is hard to remember that only a little over a century ago some places were so difficult to reach that only enormous human endeavour, allied with pain, discomfort and the very real risk of death, were required to explore the remotest of the world’s regions. And regions don’t come more hostile and remote than Antarctica, where this particular egg was collected, in 1911, as part of Robert Falcon Scott’s doomed expeditions to the South Pole.

The story behind its collection is one of almost unimaginable hardship in pursuit of a scientific dream; a story first told in The Worst Journey in the World (1922). A flavour of the book comes from this sardonic and much quoted line: ‘Polar exploration is at once the cleanest and most isolated way of having a bad time which has been devised.’

The author was far from the cynical, hard-bitten hero those words suggest; Apsley George Benet Cherry-Garrard was perhaps the least likely polar explorer in history. Short-sighted to near blindness – especially in driving Antarctic blizzards – intellectual and academic rather than naturally adventurous, and suffering a litany of physical ailments and mental illness, he was only on Scott’s expedition at all by chance. Back in 1907 he was visiting the home of his older cousin, Reginald Smith, when Scott and his long-time colleague Edward Wilson happened to drop in to discuss a new expedition to the Antarctic. Fired up by their tales of derring-do, the twenty-one-year-old decided then and there to volunteer.

Thus in 1910 Cherry-Garrard sailed on Terra Nova from Cardiff to Antarctica. At first he was not entirely welcomed by his fellow explorers, who suspected that his lack of experience and scientific knowledge (he had been given the title ‘assistant zoologist’) might prove inadequate to the daunting tasks they faced. But he was soon taken under the wing of Scott’s second-in-command, Dr Edward Wilson (known to all as ‘Uncle Bill’).

Wilson himself was a man of many talents. An accomplished artist and naturalist, a qualified medical doctor and a passionate explorer, Wilson had a theory: that close study of the embryos of birds – especially ‘primitive’ birds such as the emperor penguin – might show an evolutionary link between birds and reptiles, and thus reveal the ancestry of modern birds. To prove his theory – known as ‘recapitulation’ – Wilson had to obtain an egg. Emperor penguins nest in one of the most remote parts of Antarctica, in the middle of the southern winter, when the whole continent is shrouded in darkness and temperatures plummet.

Few men would have even considered, let alone attempted an expedition, which Cherry-Garrard later referred to as ‘a horribly dangerous and inhumanly exhausting feat’. But Wilson and Cherry-Garrard – and their companion Henry ‘Birdie’ Bowers – were made of stern stuff. And so, at the start of July 1911, the three men set off from base camp at Cape Evans to make the 100-kilometre trek inland to the penguins’ breeding colony at Cape Crozier.

They trudged at a snail’s pace in almost total darkness, in temperatures down to minus 57 Celsius – which must have been almost unbearably cold, given their primitive clothing and limited supplies. When they eventually reached their goal, a severe blizzard promptly carried away their tent, leaving them with just their sleeping bags. Thirty-six hours later the winds finally dropped, and to their amazement and great good fortune they discovered their tent, more or less intact, nearby.

They collected five eggs (two of which broke on the journey home) and then began the long march back to base, Cherry-Garrard’s teeth chattering so violently in the intense cold that they shattered. The three exhausted men and their precious cargo finally reached Cape Evans five weeks later, on 1 August. But there was no time to rest: Wilson and Bowers then joined Scott for his final push to the South Pole, while Cherry-Garrard stayed back at base with the support team. A year later, with no news from their comrades, and fearing the worst, he went in search of them, finding only the frozen tent – just a few miles from safety – where Scott and his companions had perished.

On his return to London, Cherry-Garrard took the three surviving emperor penguin eggs, for which he, Wilson and Bowers had gone through so much suffering, to the Natural History Museum. It took far longer than expected to actually look at the three eggs. The embryos were removed and then sliced and mounted on to 800 microscope slides for examination, but the First World War intervened. Richard Ashton, the museum’s specialist in embryology, then died, further delaying their examination. Eventually, when the study of the eggs was finally published in 1934 – almost a quarter of a century after they had been collected – Cherry-Garrard was told that this had not only failed to prove the (later discredited) theory of recapitulation, but that the eggs had not even taught the museum’s scientists anything useful about penguin embryology. Their quest had, it turned out, been almost entirely in vain.

Cherry-Garrard concealed what must have been enormous disappointment beneath a veneer of British stiff upper lip. His book contains several memorable reflections on the nature of polar exploration, in particular its final lines, which highlight both the bravery and futility of his particular quest:

And I tell you, if you have the desire for knowledge and the power to give it physical expression, go out and explore. If you are a brave man you will do nothing: if you are fearful you may do much, for none but cowards have need to prove their bravery. Some will tell you that you are mad, and nearly all will say, ‘What is the use?’ For we are a nation of shopkeepers, and no shopkeeper will look at research which does not promise him a financial return within a year. And so you will sledge nearly alone, but those with whom you sledge will not be shopkeepers: that is worth a good deal. If you march your Winter Journeys you will have your reward, so long as all you want is a penguin’s egg.

Cherry-Garrard went on to lead a long but quiet life, always silently reproving himself for failing to save his friends. He died, aged seventy-three, on 18 May 1959.

Since his death, Cherry-Garrard’s reputation as both a polar explorer and a writer has gone from strength to strength. He himself, though, always saw things from a wry perspective, refusing to play the martyr, and pointing out that the bird whose egg they had collected suffered far more than any human visitor to the Antarctic: ‘Take it all in all; I do not believe anybody on Earth has it worse than an emperor penguin.’

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A bear is a shaggy, slothful, wild beast, in all respect like a man, and wishful to walk upright.

Anonymous (ancient Greece)




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