page_title: Bird migration
section_title: Swallow migration versus hibernation
hierarchical_section_title: Bird migration / Historical views / Swallow migration versus hibernation
caption_attribution_description: Deutsch: Rostocker Pfeilstorch English: Rostock Pfeilstorch
context_page_description: Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by humans, and is driven primarily by availability of food. It occurs mainly in the northern hemisphere, where birds are funneled on to specific routes by natural barriers such as the Mediterranean Sea or the Caribbean Sea.
  Migration of species such as storks, turtle doves, and swallows was recorded as many as 3,000 years ago by Ancient Greek authors, including Homer and Aristotle, and in the Book of Job. More recently, Johannes Leche began recording dates of arrivals of spring migrants in Finland in 1749, and modern scientific studies have used techniques including bird ringing and satellite tracking to trace migrants. Threats to migratory birds have grown with habitat destruction especially of stopover and wintering sites, as well as structures such as power lines and wind farms.
  The Arctic tern holds the long-distance migration record for birds, travelling between Arctic breeding grounds and the Antarctic each year.
context_section_description: Aristotle, however, suggested that swallows and other birds hibernated.  This belief persisted as late as 1878, when Elliott Coues listed the titles of no less than 182 papers dealing with the hibernation of swallows. Even the "highly observant" Gilbert White, in his posthumously published 1789 The Natural History of Selborne, quoted a man's story about swallows being found in a chalk cliff collapse  "while he was a schoolboy at Brighthelmstone", though the man denied being an eyewitness. However, he also writes that "as to swallows being found in a torpid state during the winter in the Isle of Wight or any part of this country, I never heard any such account worth attending to", and that if early swallows "happen to find frost and snow they immediately withdraw for a time—a circumstance this much more in favour of hiding than migration", since he doubts they would "return for a week or two to warmer latitudes".
  It was not until the end of the eighteenth century that migration as an explanation for the winter disappearance of birds from northern climes was accepted. Thomas Bewick's A History of British Birds (Volume 1, 1797) mentions a report from "a very intelligent master of a vessel" who, "between the islands of Menorca and Majorca, saw great numbers of Swallows flying northward", and states the situation in Britain as follows:
  Swallows frequently roost at night, after they begin to congregate, by the sides of rivers and pools, from which circumstance it has been erroneously supposed that they retire into the water.
  — Bewick
  Bewick then describes an experiment which succeeded in keeping swallows alive in Britain for several years, where they remained warm and dry through the winters. He concludes:
  These experiments have since been amply confirmed by ... M. Natterer, of Vienna ... and the result clearly proves, what is in fact now admitted on all hands, that Swallows do not in any material instance differ from other birds in their nature and propensities [for life in the air]; but that they leave us when this country can no longer furnish them with a supply of their proper and natural food ... 
  — Bewick
caption: The Rostocker Pfeilstorch, found in 1822, demonstrated that birds migrated rather than hibernating or changing form in winter.
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