12.2 Essay Pigeons MH DB

OPINION DARWIN 200 NATURE|Vol 457|12 February 2009 ESSAY A flight of fancy Henry Nicholls wonders how things would be different had Charles Darwin given in to pressure from his publisher to rewrite Origin of Species into a popular book about pigeons.

“Pigeons indeed,” huffed Charles Darwin, weavers in London’s Spitalfields to Queen his brow furrowed as he read to the end of a Victoria herself. But how effective would On letter and laid it down on his desk. the Origin of Pigeons have been as a vehicle The letter contained feedback from his ffor Darwin’s ideas on evolution by natural publisher John Murray on a draft of what selection?s would become On the Origin of Species by Means of Natural Selection. Murray had CommonC descent farmed out copies of the manuscript to a ItI was just four years before he received Mur- couple of his trusted advisers. One of them, ray’sr letter, in March 1855, that Darwin found a rural vicar and literary editor by the name himselfh drawn towards fancy pigeons. For the of Whitwell Elwin, had not liked it all. “At pigeonp breeders, or fanciers, crossing different every page, I was tantalized by the absence breedsb was not just pointless (as mixed-race of the proofs,” Elwin had written to Murray offspringof lack the qualities of their parents), on 3 May 1859. In contrast to the Journal it bordered on heresy. So like the splendid of Researches (later known as Voyage of the isolationis offered by the different islands of the Beagle), which Elwin had found “one of Galápagos,G the strict racial segregation the the most charming books”, Darwin had fanciersfa imposed on their birds ensured that written this new work in a “much harderder everyeve breed was effectively isolated from & drier style”. everyeve other. Although opposed to the publi- DespiteD the birds’ striking physical cation of what he saw as “a wild and differences,dif Darwin, in line with several LIBRARY UK/THE BRIDGEMAN ART HOUSE, KENT, WOLSENHOLME/DOWN D. PIGEONS: foolish piece of imagination”, Elwin otheroth naturalists, suspected a single com- hadn’t advised Murray to reject the monmo ancestor for all the varieties — the manuscript outright. Instead, he rockro pigeon Columba livia — and he had sought the advice of the geolo- beganbe to gather evidence to support his gist Charles Lyell. It was Lyell who hunch.hu Within months, he had mugged said that the book should focus on upup on manuals, tailor-made a pigeon Darwin’s observations of pigeons hohouse for his garden and filled it with “accompanied with a brief statement dozensd of different breeds, describing of his general principles” on natural themth to Lyell as “the greatest treat, in selection. Indeed, Lyell had made a mym opinion, which can be offered to [a] similar suggestion to Darwin back in humanh being”. With abundant histori- May 1856 after being enchanted by calc information at his fingertips, and Darwin’s pigeons at Down House, Kent. byb obtaining meticulous measure- “I wish you would publish some small mentsments from adults, embryos and even blood fragment of your data [on] pigeons if you pleasel corpuscles,c he constructed a family tree for & so out with the theory & let it take date — & thet pouters, carriers, runts, barbs, fantails, be cited — & understood,” he had written. nunsn and a dozen other spectacular fancy Elwin’s final recommendation to Murray pigeonp breeds. reiterated this wish: Darwin should deliver Darwin’s foray into breeding gave him a slimmer volume that homed in on this one yety more evidence in favour of the pigeons’ well-worked case study. “Every body is inter- commonc descent. A cross of any two vari- ested in pigeons,” Elwin observed. eties,e he found, produced fertile offspring. Before considering Darwin’s response to What’sW more, the offspring of these crosses that suggestion, it is worth taking a moment to ofteno sported characteristics not found in reflect on what might have been On the Origin eithere parent but that did appear in the rock of Pigeons. Such a volume would, Elwin had pigeon.p So in spite of their extraordinary suggested, “be reviewed in every journal in the visiblev differences, some underlying same- kingdom & would soon be on every table”. He nessn united all the fancy varieties. All this, was probably right. Breeding ‘fancy’ pigeons anda more, eventually wound up in his 1868 was an extraordinarily popular pastime in Despite their striking physical differences, Darwin bookb on The Variation of Animals and Plants Victorian Britain, with enthusiasts spanning suspected that the various breeds of ‘fancy’ pigeon Under Domestication. the entire social spectrum, from the poorest shared a common ancestor. Darwin’s pigeons also served another

purpose, one that’s harder to detect in his pub- lished writings. By crossing different breeds and observing how traits were passed from one generation to the next, he hoped to bring some clarity to the frequently confused thinking on inheritance. Research on the mass of pigeon skeletons and skins that Darwin left to the Nat- ural History Museum in London promises to shed fresh light on the precise lines of enquiry he pursued. But even with more information, see- ing pigeons as Darwin saw them will be extraordinarily tricky because it requires unimagining so much of what we now take for granted. At the very least, you must unravel the double-helix, knock out the gene and banish the concept of chromosomes. Then you must populate your mind with what are, by today’s stand- ards, some very strange notions. Take pre-potency, for example, the idea that when two different breeds are crossed, one makes a greater contribu- tion than the other to the offspring. In a version of this, known as Yarrell’s law, it was proposed that the older breed would always dictate the characteristics of the next generation. Another commonly held belief was that males were respon- sible for defining the external characteristics of Publisher John Murray (top) relayed to Darwin the advice of Charles Lyell, who the offspring and females the internal features. felt that pigeons would best communicate his theory of natural selection. Evidence from Darwin’s notebooks, letters and unpublished manuscripts suggests that would have failed to capture the extraordinary better, if they had my the outcomes of the crosses he performed ran scope of natural selection’s explanatory power. materials; but that is counter to each of these widely held beliefs. That was Darwin’s crucial aim — to demon- no help.” Unfortunately, however, the complex genetic strate the impact of natural selection “on geo- Persuaded by Dar- basis for the traits he was looking at meant his graph. distribution, palaeontology, classification win’s determination, pigeon crosses failed to reveal the true par- Hybridism, domestic animals & plants…”. In Murray agreed to ticulate nature of inheritance, something that 1856, he set about writing the book that would publish, making lit- would have to wait for the discovery of Gregor do this, a work he called Natural Selection. He tle editorial input otherer thanthan Mendel’s work at the turn of the century. was still at it almost two years later when he to clip the first five words from the proposed received the now infamous letter from Alfred title — An Abstract of an Essay on the Origin of Unnatural selection Russel Wallace that outlined the same idea. This Species and Varieties Through Natural Selection. Although Darwin’s work on pigeons failed unexpected circumstance forced Darwin to Darwin subsequently made a few further tweaks to unravel many of the mysteries surround- shelve what would have been a massive, multi- to give us the title we celebrate this year. ing inheritance, it did make a volume magnum opus (about Darwin’s gambit — to convince his audience marvellously persuasive case “On the Origin of two-thirds of which he had of evolution by natural selection by showing for the origin of new varieties already written), and work furi- the extraordinary breadth of its explanatory by means of artificial selection. Pigeons would have ously for the next ten months to power — proved remarkably effective. We owe From there, it was a simple step failed to capture the bash out a shorter ‘abstract’. a debt of gratitude to Wallace for denying us to argue, by analogy, for the extraordinary scope So how did Darwin feel that the thudding great tomes of Natural Selection origin of species by means of morning when he received and to Darwin for depriving us of a pithy little natural selection. But would of natural selection.” Elwin’s feedback on this con- book on pigeons. On the Origin, with its light On the Origin of Pigeons, had densed version? Probably a bit touch and wide-ranging content, sits comfort- it been written, have conveyed the enormity of rotten. Elwin’s criticisms — that it was thin ably between these two extremes. ■ Darwin’s idea? on evidence and stylistically wanting — hit Henry Nicholls is a science writer who lives A few of the more observant and imaginative on the two weaknesses that he often worried in London. His most recent book is Lonesome readers might well have seen Darwin’s broader about. But if he did contemplate writing the George: The Life and Loves of a Conservation Icon. message. For many more, however, the wonder desired pigeon book, it was not for long. “It is of the fancy breeds would have been the main my deliberate conviction that both Lyells & For further reading, see http://tinyurl.com/bwjsl5. show, and the link between artificial and natural Mr Elwyns suggestions … are impracticable,” For more on Darwin, see www.nature.com/darwin. selection an unnecessary distraction. Perhaps he wrote back to Murray. “I have done my best. Listen to Henry Nicholls on the Nature podcast at more importantly, On the Origin of Pigeons Others might, I have no doubt, done the job www.nature.com/nature/podcast. LIBRARY PHOTO ENGLISH HERITAGE OF SCOTLAND/ LIBRARY OF THE NATIONAL OF THE TRUSTEES COURTESY