By Tim Birkhead
If you’ve ever been birding in South America, you’ll know how difficult certain groups, such as the woodcreepers (Dendrocolaptinae) for example, are to identify. Without a local guide you’d struggle to distinguish one species from another, at least at first. The fact that your guide can identify the different species of woodcreeper is partly due to the efforts of scientific ornithologists studying museum skins and deciding where one species starts and another stops.
Nowadays, we take it for granted that we can identify most bird species, but it wasn’t always like this. Early ornithologists often found it extremely difficult to distinguish one species from another, especially in groups like raptors, waders and warblers. Our knowledge of birds goes back to at least 350 BC, when Aristotle attempted the first classification of birds, referring to those he knew by name, but missing or ignoring many others. Much later, in the 1500s, the Cambridge scholar William Turner laboriously worked his way through Aristotle’s writings to identify the 140 species Aristotle had recorded. This is about half of what we might find in rural Greece today, suggesting that Aristotle missed a fair few.
For centuries Aristotle was the natural history authority that no-one dared to challenge. The authors of natural history encyclopedias of the 1500s and early 1600s – Conrad Gessner, Pierre Belon and Ulisse Aldrovandi – repeated verbatim much of what Aristotle had written. By today’s standards, these huge, unwieldy volumes seem bewildering, not least because the concept of natural history was so different then, encompassing moral instruction, folklore and magic as well as ‘natural history’. Confusion was rife and knowing exactly what species these authors were referring to was often a problem. By copying earlier authors’ works uncritically, they perpetuated or compounded previous mistakes. Many bird species were known by several different names; some different species were known by the same name; and in many sexually dimorphic species, males and females were considered different species.
One reason why the identification and study of birds was a mess was the huge reluctance to challenge Aristotle’s authority or to add to his observations. It was assumed that Aristotle had done it all, and the idea of being able to improve on his writings was anathema. It was a cultural roadblock.
But then, in the early 1600s, the scholar Francis Bacon began to realise that there was new knowledge to be had and new species to be described, a view brought into sharp focus by the discovery of North America. This realisation was the beginning of what became the scientific revolution – the collection of objective information. This new attitude to knowledge involved not taking anyone’s word for it: not seeing what you believed (as Aristotle and his followers did), but believing only what you saw with your own eyes (Wootton 2015).
The community of scholars in England in the 1600s was tiny and the growth of ‘science’ was initially slow. But by the middle of the century the idea of change had taken hold among scholars in England’s two universities. In Oxford, a group of men met on a regular basis to discuss scientific issues, and it was they who founded England’s premier scientific organisation, the Royal Society, in 1660. In Cambridge, another group of men, including John Ray and Francis Willughby, fascinated by the ‘new science’, were busy dissecting birds, conducting chemical experiments and investigating the life-cycles of animals and plants (Birkhead 2018).
John Ray, a brilliant mathematician and botanist, served as tutor to the 17-year-old Francis Willughby when he went up to Trinity College in September 1652. Willughby’s family was landed gentry, but in contrast to other undergraduates sufficiently wealthy not to need to study for a profession, he took to scholarship like a duck to water. He and Ray became firm friends and they scoured the Cambridge countryside together in search of new plants as Ray prepared a local flora. Their discussions ranged widely and both were fired up by the new approach to understanding the natural world. Their journeys extended further and further across Britain and it was on one of these trips, in 1662, that they made a momentous decision to completely overhaul the study of natural history.
This bold idea was inspired by the new scientific way of thinking. Part of this was the recognition that classification was the key to knowledge because it allowed the imposition of order on what had previously been chaos. Earlier authors interested in birds had either failed to devise any kind of classification at all (like Gessner), or created schemes that were biologically unrealistic (like Aristotle, Belon and Aldrovandi).
Willughby and Ray also realised that sound classification was built on unambiguous identification. Try to put yourself in their position. Much of the previously published information was untrustworthy. Their only option was to start from scratch and make their own identifications and establish what it is that distinguishes one bird species from another. There was no birdwatching culture and there were no binoculars; the only way to do this was to look at specimens. Willughby searched continental food markets for material, received gifts of dead birds from friends and shot a few himself.
Francis Willughby is the pioneer of bird identification. He focused on what he called ‘characteristic marks’ – features that distinguished one species from another. Willughby’s remarkable innovation anticipated by more than 250 years the system that Roger Tory Peterson later made famous in his field guides. Willughby was sharp-eyed, and scrutinised his specimens in a systematic manner. Starting with the head, he worked his way from the beak, mouth, tongue, and eyes, across the plumage, noting the numbers of wing and tail feathers until he reached the feet, legs, toes, and claws. He then opened the bird up, noting its internal characteristics: the structure of its syrinx, the presence or absence of a gall bladder, the size of its gonads and the length of the gut. For example, he noted (quite correctly) that the Dunnock Prunella modularis had ‘large testicles’.
Colour was a problem: seventeenth-century books were published in black and white and illustrations were woodcuts or engravings. Willughby was forced to describe the colour of feathers and bare parts using terms that his readers would be familiar with. The colour of the upperparts of a Song Thrush Turdus philomelos were likened to ‘unripe pickled olives, such as are brought over to us out of Spain’.
Classification was the main goal and Willughby and Ray both worked on their own systems. The scheme that eventually appeared in their book was based on a bifurcating system, a dichotomous key: dividing birds first into land and water species, then, using anatomical features such as beaks and feet, into smaller and smaller categories until it got down to species. Their aim was that by using their key one could identify pretty well any species.
Sadly, Francis Willughby did not live long enough to see his book in print. In June 1672, he was struck down with a fever and a month later he was dead. He was just 36. Before he died, Ray agreed to take care of his sons’ education and to see Willughby’s works on birds, fish and insects into print. And, over the next 30 years, Ray did just that. First to appear was the book on birds that Ray entitled The Ornithology of Francis Willughby. Published first in Latin in 1676, it appeared in English (with some additions) two years later. The Ornithology – as it is popularly known – was hailed as a breakthrough. Indeed, Carl Linnaeus later based his system of bird classification on Willughby and Ray’s work.
As well as publishing books on both fish and insects using Willughby’s notes, Ray published his own books on plants, and perhaps most famously on a philosophy of natural history, The Wisdom of God, a book that ingeniously combined Protestant belief with sensible scientific explanations of the natural world. Ray was a genius, and because of this, and the fact that he outlived Willughby by over 30 years, it was eventually assumed that Ray was the real brains behind the Willughby–Ray endeavours (the story is much more intriguing than that, but space here is limited). Willughby eventually became a footnote, downgraded to a mere enthusiastic amateur. Not true! During a recent three-year project, a team of 14 science historians and myself delved into Willughby’s little-known life, discovering that he too was a genius, albeit of a different sort from John Ray. In fact, their different personalities and talents beautifully complemented each other and it was this that allowed them to succeed so brilliantly.
Scientists are typically remembered for specific discoveries: Joseph Lister, antiseptic; Edward Jenner, smallpox vaccine; Alexander Fleming, penicillin; Watson and Crick, the structure of DNA. We cannot ‘define’ Willughby (or Ray) in terms of any single large discovery. Rather, what Willughby discovered was a way of doing science, and of doing ornithology in particular. Working out how to identify different species from their characteristic marks and then using that information to construct a biologically sensible classification.
But Francis Willughby did make one discovery, and it is one that has been largely overlooked: he was the first to distinguish the Honey-buzzard Pernis apivorus from the Common Buzzard Buteo buteo:
It differs from the common Buzzard: 1. in having a longer tail; 2. an ash-coloured head; 3. the irides of the eyes yellow; 4. thicker and shorter feet; and 5. in the broad transverse dun beds or strokes in the wings and tail; which are about three inches broad (Ray 1678).
Later, the great Victorian ornithologist (and misogynist) Alfred Newton disagreed, and in his monumental Dictionary of Birds (1893–96), asserted that in 1555 Pierre Belon in his L’Histoire de la nature des oyseaux had already made the distinction. But Newton’s French wasn’t as good as he thought, and our examination of Belon’s original shows that he muddled the two buzzard species, among other things saying that the Honey-buzzard could be caught in winter (when, of course, it would be in Africa). Willughby, together with Ray, was the first to distinguish and describe the European Honey-buzzard (Birkhead et al. 2018).
Willughby’s success as a naturalist was eventually celebrated, albeit modestly, by fish biologists, entomologists and botanists, by naming (respectively) a char, a bee and genus of plants after him (Charmantier et al. 2016). It is ironic, however, that Willughby, who is best remembered for the Ornithology, never had a bird named after him. Given that the European Honey-buzzard’s name is inappropriate (it is not exclusively European and it doesn’t eat honey), changing it to ‘Willughby’s Buzzard’ would seem entirely justified. It would also celebrate the life and work of our greatest ornithological pioneer (Birkhead et. al. 2016; Birkhead 2018).
Birkhead, T. R. 2018. The Wonderful Mr Willughby: the first true ornithologist. Bloomsbury, London.
―, Charmantier, I., Smith, P. J., & Montgomerie, R. 2018. In press. Willughby’s buzzard: names and misnomers of the European Honey Buzzard. Archives of Natural History.
Charmantier, I., Johnston, D., & Smith, P. J. 2016. The legacies of Francis Willughby. In Birkhead, T. R. (ed.), Virtuoso by Nature: the scientific worlds of Francis Willughby FRS (1635–1672), pp. 360–385. Koninklijke Brill NV, Leiden.
Newton, A. 1893–96. A Dictionary of Birds. A & C Black, London.
Ray, J. 1678. The Ornithology of Francis Willughby. London.
Wootton, D. 2015. The Invention of Science: a new history of the scientific revolution. HarperCollins, London.
Tim Birkhead is professor of evolution and behaviour at the University of Sheffield. He has studied and written about birds for 40 years.