In September, one of the wildlife spectacles that distinguishes this part of the world can be seen in the Yukon's skies. In the fall Sandhill Cranes migrate to their wintering grounds in the southern United States. In the space of a few days, huge flocks of these birds will pass over the Yukon. About half of the more than 500,000 Lesser Sandhill Cranes in the world migrate across the territory in the spring and fall. A few of the cranes breed on the Yukon s North Slope, but most of the birds continue on to western Alaska.
Some cranes even cross the Bering Sea and breed in northeastern Siberia.
Lesser Sandhill Cranes migrate two to three times further than other Sandhill Cranes, with some of them travelling as much as 22,000 kilometres in a year. They are also the most abundant of the three migratory subspecies of Sandhill Cranes in North America. Many different bird species follow the trench as it offers them a low elevation route across the Yukon. Records on the Sandhill Crane migration in the Yukon date back to 1904, but not many observers have documented the migration. The cranes usually fly only during the day, roosting at night in open areas.