Context: It has been possible to teach a migration route to a flock of birds, for example in re-introduction schemes. After a trial with Canada geese Branta canadensis, microlight aircraft were used in the US to teach safe migration routes to reintroduced whooping cranes Grus americana.

Question: What is a re-introduction scheme?
Answer: to teach a migration route to a flock of birds

Question: What did they use to teach birds a migration route?
Answer: microlight aircraft

Question: Which birds did they reintroduce to the US?
Answer: whooping cranes

Question: Which birds did they use as a trial run?
Answer: Canada geese