Climate change is also disrupting the weather patterns that help animals know when to begin their migration. How can we save wild animals from extinction?
The CMS or Bonn Convention, signed in 1979, helps countries coordinate efforts to protect migratory species on their routes. The parties meet every two to three years to monitor progress and formulate new plans.
Thanks to the convention, animals like the saiga antelope of Central Asia face less habitat loss and poaching. Many species of migratory sharks can also find safe haven in marine protected areas, and albatrosses are rarely killed by fishing trawlers.
But migratory species are at risk from climate change and habitat loss. Conservation groups say more needs to be done to protect this important group of animals, including preserving and restoring habitat and removing barriers along migratory corridors.
These great migrants play important roles in the ecosystem such as pollinating plants, spreading seeds, forming part of the food web. They also have immense cultural significance, inspiring art, religion and literature.