Most birds are believed to migrate seasonally.
Hibernation theory
- It was believed that birds hibernated underwater or buried themselves in.
- 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 and thought they then turned into robins.
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 in winter.
Scientific developments
- In 1822, a stork was killed in Germany which had an African spear in its.
Previously there had been no that storks migrate to Africa.
- Little was known about the 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 ‘’ of dead birds.
- In 1931, the first to show the migration of European birds was printed.
GIẢI THÍCH CÂU 1
Đối với dạng bài Summary Completion, cần phải xác định dạng từ --> điền 1 noun
Nghe thấy Take hibernation theory for example --> biết sắp đến câu trả lời nhờ vào subheading
Nghe tiếp Another theory for the regular appearance and disappearance of birds was that they spend winter hidden in mud
-->Những con chim này dành cả mùa đông trốn trong bùn (mud). hidden in mud = buried themselves in mud
--> điền mud
Lưu ý
- Nội dung giải thích được viết bởi DOL IELTS Đình Lực - Học Viện Tiếng Anh Tư Duy đầu tiên tại Việt Nam
- Đề được viết bởi nhà xuất bản lớn gồm Cambridge và Oxford