In the early 15th century, Spanish adventurers returning from the Canary Islands brought home some unlikely souvenirs-little finches they called canary-birds. The grey-green birds weren鈥檛 much to lookat, but when they opened theirthroats, out came the sweetest song. Canaries were soon a favourite pet in the palaces of Europe, so rareand costly thatonlythe wealthiest could afford them. Until, that is, some enterprising German bird keepers persuaded captive canaries to breed and began to generate a steady supply. With careful pairings, they went on to produce birds with sweeter voices. And by 1677, the German bird men had conjured up a canary that looked as pretty as it sounded: it was pure yellow. That, at least, is theaccepted version of howthe canary acquired itsfamiliarcolour. Yetan illustration in a prince鈥檚 schoolbook nearly 200 years earlier suggests that at least one Italian bird keeper already knew the secret of selective breeding.
CANARIES are yellow and live in cages. Tame and friendly, they interrupt their singing only to peck at a head of millet. Canaries have been part of the domestic scene for so long it鈥檚 hard to imagine them as anything else. But on their native islands in the Atlantic, flocks of wild grey-green canaries forage in the fields and forests. The familiar golden songster is the product of patient selective breeding in an age when caged birds were captured, not bred.
Although the Romans had dealings with the Canary Islands, they more or less dropped off the map until 1402 when the Norman adventurer Jean de Bethancourt claimed them for the king of Spain. Settlers and visiting sailors were enchanted by the song of the cock canary and soon the inconspicuous little birds were on their way to Spain. The first birds were so rare and precious they were exchanged as gifts between royal houses, spending their lives in extravagant gilded cages in the courts and castles of Europe.
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Before long hundreds of birds were being shipped to Europe. For the island bird catchers and their Spanish middlemen, business was good: they sold only cock birds and they were prone to diseases, ensuring regular repeat orders. Any bird keeper contemplating breeding their own birds would first have to lay their hands on some females. In any case, keepers were not breeders. They worked with birds taken from the wild. Their skills lay in raising nestlings to produce pets that were happy in their cages, and then to keep them alive and healthy.
Even a century and a half after they were introduced to Europe, the birds remained the preserve of the rich. As German ornithologist Conrad Gessner pointed out in his Historiae Animalium in 1555: 鈥淚t is sold everywhere very dear, both for the sweetness of its singing, and also because it is brought from far remote places with great care and diligence, and but rarely, so that it is wont to be kept only by nobles and great men.鈥�
But Gessner鈥檚 compatriots eventually broke the Spanish monopoly by breeding canaries in captivity. 鈥淔or most birds there was little incentive to breed your own when you could take them from the wild. But canaries were hard to get and so the motivation to breed them was strong,鈥� says Tim Birkhead, author of The Red Canary, in which he follows the quest to create an even more colourful canary. Although the Spanish tried to keep hen birds from reaching Europe, the sexes look alike and some clearly slipped through.
鈥淭he first birds were so rare and precious they were exchanged as gifts between royal houses and spent their lives in extravagant gilded cages鈥�
Germany became a centre for canary breeding, and began to supply more affordable birds to enthusiasts all over Europe. Once they had begun to breed them, they found they could change them. They produced birds with crests and birds with sweeter songs. And they turned the green canary yellow.
In the 1920s, German ornithologist Erwin Stresemann unearthed three pictures of canaries painted in 1610 by Lazarus R枚ting. Two were grey-green but the third had white wings and yellow patches on its body. This, he suggested, marked the start of the transition from green to yellow. The change was complete by 1677 鈥� the date of the first written reference to an all-yellow canary. Stresemann concluded that it had taken 60 or 70 years to breed all-yellow birds. This fits with what we now know about the genetics of colour in canaries, says Birkhead.
The canary鈥檚 colour is controlled by several different genes, making it a difficult trait for a breeder to fix and maintain. Producing a stable line of yellow birds would have taken many decades 鈥� unless a mutant yellow canary had popped up in the wild, providing a fast track to a golden variety. Random mutation throws up such 鈥渟ports鈥� among greenfinches, but no one has ever seen a wild yellow canary. The reason is simple: in greenfinches, colour is controlled by a single gene and one mutation is all that鈥檚 needed. With a population in the millions that is likely to happen occasionally. With several genes at work, and a total wild population of just 160,000 or so, the likelihood of it happening in canaries is vanishingly small, says Birkhead.
Without an easy starting point, potential breeders were in for a long haul. Astonishingly, it now appears that someone began the process within a few years of the canary鈥檚 arrival in Europe. New 鈥渟ightings鈥� of yellow canaries have recently come to light suggesting the transformation took place in Italy perhaps as early as the late 1400s. The earliest of these sightings is in a painting in a Latin grammar handwritten and illustrated around 1495. This was no ordinary schoolbook, but a one-off written for Maximilian Sforza. The Sforzas were the ruling family in Renaissance Italy. Maximilian would succeed his father as Duke of Milan, but in 1495 he was a small boy of five or six. The painting shows two of the prince鈥檚 playmates, each holding a yellow bird. The birds are not named but they look like canaries, they are clearly tame and they are being fed seeding heads of millet. 鈥淭his is very telling. Millet is a favourite food of canaries,鈥� says Birkhead.
The Italian connection crops up again 50 years later. In his Historiae Animalium, Gessner remarks on the existence of a part-yellow canary with a golden breast. These birds, he noted, came to Germany from Italy, and were distinctive enough to be given a special name, uccello d鈥檕ro, or 鈥済olden bird鈥�. Birkhead thinks this is good evidence that the Italians were selectively breeding canaries by this time.
So why didn鈥檛 Italy鈥檚 bird breeders become famous for their yellow canaries? Perhaps their success came too soon. Or perhaps once they had cracked the secret of breeding the coveted new canary, they were unable to keep the line going. In the 15th century, canaries were status symbols. 鈥淚f the Royal palace had a bird keeper and he created a yellow canary it would be so highly prized they wouldn鈥檛 let it out of their sight,鈥� says Birkhead. They would flaunt them but they wouldn鈥檛 be giving any away.
In any case, the bird keeper鈥檚 success might have been short-lived. 鈥淭here would be a good chance the yellow birds would go extinct,鈥� says Birkhead. 鈥淚t鈥檚 hard to maintain these lines. The genes are recessive and you keep them going by crossing and backcrossing and hoping that some of the offspring carry the same trait. But you end up with a pool of inbred birds and they are more likely to die out.鈥�
Yellow birds might have appeared in Italy in the 1400s, but the chances are they died out and the Germans had to start from scratch. 鈥淚t鈥檚 likely several attempts were made at breeding them and several people got yellow ones independently,鈥� says Birkhead.
In the 19th century, Charles Darwin admired the amazing skills and knowledge of animal breeders, and used their extraordinary varieties of pigeons and chickens to illustrate his ideas about natural selection. But in the 15th century, a bird keeper who bred from his birds would have been breaking entirely new ground. 鈥淚f as early as 1490 they had the skills to capture the genetic variation and maintain it using rules of thumb then they were extraordinarily skilful,鈥� says Birkhead. Maximilian鈥檚 yellow canaries suggests they were.