Sunday, November 7, 2010

Tundra Swan 1

On Friday Erika and I took a road-trip to extreme southeastern Minnesota, just south of Brownsville.  We hoped to see flocks of Tundra Swans.  We had no trouble finding the swans.  Just south of Brownsville, the Fish and Wildlife Service has built two overlooks just where the swans are most easily seen.  We saw hundreds.
Tundra Swans breed in arctic Canada and Alaska and winter either in the Pacific Northwest or in the Chesapeake Bay region.  Swans heading towards the bay fly across much of the northern Great Plains.  These birds rest up and refuel near Devil's Lake in North Dakota and in the upper Mississippi Valley in southeastern Minnesota.  They leave the arctic in late September and arrive in Minnesota in early October.  They leave here and make a non-stop migration to the Chesapeake (1600 km), arriving on the East Coast from mid-November through December.  (Western Swans rest in Utah, before proceeding to California and Oregon.)
Tundra Swans migrate in family groups within flocks that can be over 100 birds. Before mating at 2 or 3 years, young swans may "date" other swans.  Once mated they are monogamous and remain together all year.  Divorce is rare, although presumably they will remate if one of the pair dies. (Much of this information is from Limpert and Earnst 1994).

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