Most birds are believed to migrate seasonally.



Hibernation theory

• It was believed that birds hibernated underwater or buried themselves in

  1

  mud
  .

• This theory was later disproved by experiments on caged birds.



Transmutation theory

• Aristotle believed birds changed from one species into another in summer and winter.

- In autumn he observed that redstarts experience the loss of

- Aristotle's assumptions were logical because the two species of birds had a similar



17th century

• Charles Morton popularised the idea that birds fly to the

  4

  moon
   in winter.



Scientific developments

• In 1822, a stork was killed in Germany which had an African spear in its

  5

  neck
  .

- previously there had been no

• Little was known about the

  7

  destinations
   and journeys of migrating birds until the practice of ringing was established.

- It was thought large birds carried small birds on some journeys because they were considered incapable of travelling across huge

- Ringing depended on what is called the ‘

• In 1931, the first

  10

  atlas
   to show the migration of European birds was printed.