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.
وهي تطير عادة على ارتفاع يتجاوز الـ‍ ٥٠٠ متر ،‏ لذا تكون رؤيتها بالعين المجردة شبه مستحيلة .‏