Bird migration routes have been studied by a variety of techniques including the oldest, marking. Swans have been marked with a nick on the beak since about 1560 in England. Scientific ringing was pioneered by Hans Christian Cornelius Mortensen in 1899. Other techniques include radar and satellite tracking. COUNT 5
QSN1 What is the oldest way to study migration? ANS1 marking QSN2 How have swans been marked? ANS2 a nick on the beak QSN3 Who was scientific ringing pioneered by? ANS3 Hans Christian Cornelius Mortensen QSN4 Since when have swans been marked? ANS4 1560 QSN5 What are other forms of studying migration? ANS5 radar and satellite tracking