"Migration routes" refers to the paths or routes that animals or people take when traveling from one place to another during migration. Full definition
We are investigating the best means of monitoring whale migration routes at all three islands. (andbeyond.com)
Furthermore, the time it takes to gain settlement rights is out of line with the time it takes to gain the same rights through other migration routes, such as the employment route. (politics.co.uk)
They invariably conclude that wind farms may be built in the habitat of rare birds, or across migration routes. (savetheeaglesinternational.org)