Annals of the Royal College of Surgeons of England (I978) vol 6o HUNTERIANA John Hunter, Gilbert White, and the migration of swallows I F Lyle, ALA Library of the Royal College of Surgeons of England Introduction fied than himself, although he frequently sug- gested points that would be worthy of investi- This year is not only the 25oth anniversary of gation by others. Hunter, by comparison, was John Hunter's birth, but it is also I90 years the complete professional and his work as a since the publication of Gilbert White's Nat- comparative anatomist was complemented by ural History and Antiquities of Selborne in White's fieldwork. The only occasion on which December I788. White and Hunter were con- they are known to have co-operated was in temporaries, White being the older man by I768, when White, through an intermediary, eight years, and both died in I 793. Despite asked Hunter to undertake the dissection of a their widely differing backgrounds and person- buck's head to discover the true function of the alities they had two very particular things in suborbital glands in deer3. Nevertheless, common. One was their interest in natural there were several subjects in natural history history, which both had entertained from child- that interested both of them, and one of these hood and in which they were both self-taught. was the age-old question: What happens to In later life both men referred to this. Hunter swallows in winter? wrote: 'When I was a boy, I wanted to know all about the Background and history clouds and the grasses, and why the leaves changed colour in the autumn; I watched the ants, bees, One of the most contentious issues of eight- birds, tadpoles, and caddisworms; I pestered people eenth-century natural history was with questions about what nobody knew or cared the disap- anything about". pearance each autumn of a number of species of birds-swifts, swallows, and martins in par- White's comment was remarkably similar: ticular-and their reappearance the following spring. This was no new problem for the phe- 'It has been my misfortune never to have had any nomenon was known to the Greeks, but it had neighbours whose studies have led them towards never been established what happened to the the pursuit of natural knowledge: so that, for want birds in their absence. Two main theories had of a companion to quicken my industry and shar- been propounded: either they pen my attention, I have made but slender progress migrated to in a kind of information to which I have been at- warmer latitudes during the colder months or tached from my childhood'2. else they hibernated. Neither explanation had ever been satisfactorily proved, although both Secondly, both men had the gift of observat- had been put forward from the time of ion, which they used at a time when philo- Aristotle. sophic speculation was more fashionable. Much 'A great number of birds also go into hiding; they of what they saw could have been seen by do not migrate, a.s is generally supposed, to warmer other men had they chosen to look, but in this countries. Thus certain birds (as the kite and the White and Hunter were before their time. swallow) when they are not far off from places of White was an amateur, the first real field- this kind, in which they have -their penranent naturalist and the founder of the great tradit- abode, betake themselves thither, others, that are at a distance from such places, decline the trouble of ion of amateur natural historians. However, he migration and simply hide themselves where they knew his limitations and seldom performed are. Swallows, for instance, have often been found dissections, which he left to others better quali- in holes, quite denuded of their feathers . .'4. 486 I F Lyle In the early sixteenth century a Bishop of grated to the moon for the winter. The growth Uppsala, Olaus Magnus, in his Historia de of interest in natural history at this time pro- Gentibus Septentrionalibus claimed that swal- duced a greater awareness of the subject lows had been found hibernating under water5 among travellers, who brought fresh observat- and illustrated his text with a woodcut ions to supplement the many old and distorted showing fishermen pulling the birds ashore in stories that were then extant. These new ac- their nets. Unlikely as it was, this startling re- counts were eagerly seized upon by naturalists port was used as a basis for many similar ac- at home who then fiercely argued their signifi- counts and alleged observations until at least gance. One of these new accounts was related the end of the eighteenth century. Robert Bur- by Pierre Adanson in his Voyage to Senegal: ton, for example, mentions it in his Anatomy of Melancholy: 'The 6th of the same month [October I7491 at half past six in the evening, we were about fifty leagues from the coast, when four swallows came to take '. What becomes of Swallows, Storks, Cranes, their night's lodging in our vessel, and pitched Cuckows, Nightingales, Redstarts, and many other upon the shrouds. I catched them all four with kind of singing birds . Do they sleep in winter, great ease, and found them to be European swal- like Gesner's Alpine mice; or do they lye hid (as lows. This lucky incident confirmed me in the sus- Olaus affirms) in the bottom of lakes and rivers, picion that I had formerly entertained; that those spiritum continentes? often so found by fishermen birds crossed the sea to get into the torrid zone, as in Poland and Scandia, two together, mouth to soon as winter approached: and that I have ob- mouth, wing to wing; and when the spring comes served since, that they are never seen but at this they revive again, or if they be brought into a time of year at Senegal . when the cold drives stove, or to the fireside. Or do they follow the Sun them away from the temperate countries of Europe. ... or lye they hid in caves, rocks and hollow trees, Another fact not less worthy of remark, is, that as most think . the swallows do not build their nests in Senegal as in Europe . .'8. Not all naturalists were prepared to give credence to the hibernation theory. Francis A similar observation was made by Admiral Sir Willughby and his friend John Ray, the great Charles Wager, published in I760 by Peter English naturalist of the seventeenth century, Collinson, a naturalist and Fellow of the Royal expressed doubts about it in Willughby's Orni- Society, who was a strong advocate of the thologia of I676 (English edition I678). Al- migration theory: though Willughby died in i672, Ray arranged and edited the material for publication, so we 'I have often heard Sir Charles Wager . relate may assume that it reflected his view as well. that in one of his voyages home, in the spring of the year, as he came into soundings of our channel, a great flock of swallows came and settled on all 'What becomes of Swallows in Winter time, his rigging: every rope was covered, they hung on whether they fly into other countries, or lie torpid one another like a swarmn of bees; the decks and in hollow trees, and the like places, neither are carvings were filled with them; they seemed almost natural historians agreed, nor indeed can we cer- spent and famished, and were only feathers and tainly determine. To us it seems more probable that they fly away into hot countries, viz. Egypt, bones; but being recruited with a night's rest, they Aethiopia, etc. then [sic] that either they lurk in took their flight in the morning'9. hollow trees, or holes of Rocks and ancient build- ings, or lie in water under the ice in Northern Collinson sent this paper to Linniaeus, with Countries, as Olaus Magnus reports.'7 whom he maintained a correspondence be- tween 1738 and I767. Linnaeus was a 'hiber- Up to this time most writers put forward nationist' who believed in Olaus Magnus' tales both hibernation and migration as possible of birds hibernating under water. Several of explanations, but this situation changed in the Collinson's letters were taken up in trying to eighteenth century, when naturalists became persuade him to perform experiments and dis- more dogmatic in their opinions and tended to sections, the results of which, Collinson was polarise into definite 'migrationist' and 'hiber- convinced, would show that underwater hiber- nationist' camps. At the same time another nation by swallows was impossible. Linnaeus theory, fortunately shortlived, arose to confuse never took up the challenge, but Collinson's matters. This was the idea that swallows mi- suggestion was significant"0. John Hunter, Gilbert White, and the migration of swallows 487 Gilbert White - observations and doubts 'As to swallows (hirundinae rusticae) being found in a torpid state during the winter in the isle of Most of the material published in the Natural Wight, or any part of this country, I never heard History and Antiquities of Selborne (hereafter any such account worth attending to. [He then referred to simply as Selborne) was never inten- goes on to describe two such cases.]"' ded for publication. It was originally contained in letters written by White to two fellow-natu- In White's opinion any evidence of hibernation ralists, Thomas Pennant and the Hon. Daines did not hinge upon such accounts, which were Barrington. Pennant was one of the leading probably distorted and unreliable anyway. In- naturalists of the day and a writer of popular stead it lay in the fact that the young birds travel books.