Their annual migration is up to 9,300 miles (15,000 km) long, beginning from as far north as the fringes of the Arctic and terminating as far south as tropical West Africa.
Nende iga - aastane ränne, mille kogupikkus on kuni 15 000 kilomeetrit, võib alata Arktika äärealadelt ja lõppeda troopilises Lääne - Aafrikas.