Billions of animals are regularly on the move anually. These species migrate on land, in water and in the sky. Migratory species include some of the most iconic species on the planet such as sea turtles, whales and sharks in our oceans, elephants, wild cats, and herds of hooved species that cross plains and deserts, raptors, waterbirds and songbirds that cross through the skies, and even insects such as the monarch butterfly. They travel frequently, sometimes thousands of miles, to reach places where they breed or feed, but they also face enormous challenges and threats along the way. When species cross national borders, their survival depends on the efforts of all the countries in which they are found.