Swan's song key to ID

MAT-SU - The distinct call of the trumpeter swan reveals the origin of its name. A flock of trumpeter swans, historically referred to as a ballet, sounds like an orchestra filled with French horns.

The swans' vocalization remains the best way to distinguish between the trumpeter and the tundra swan, according to Tom Rothe, wildlife biologist with the Alaska Department of Fish and Game.

Trumpeters make a loud, low-pitched and resonant sound, according to Rothe.

The tundra swan, also known as the whistling swan, emits a high-pitched whooping call, he said.

It sounds like &#8220who-who-ho,” or &#8220woo-oo-woo,” with the middle of the call accentuated, according to a trumpeter swan Web site that explains how to identify swans and geese.

While some trumpeter swans nest in the Valley and tundra swans call the Yukon-Kuskokwim delta home during the summer, both species will be present in the Mat-Su as the birds prepare to migrate, Rothe said.

It's not uncommon for the two species to mingle prior to migration and in their winter range, according to the Web site.

&#8220There are only 20,000 trumpeter swans in the world. Ninety percent of the world's population nests in Alaska. A fair number in the Cook Inlet, Copper River, Gulkana Basin - big lake country,” Rothe said.

The trumpeter migrates to parts of Washington and British Colombia, he said.

The tundra swan population is much stronger, with 80,000-100,000 nesting in western Alaska, Rothe said. The whistling swans' winter ranges take the bird to parts of California.

Bird-watchers and sportsmen who come into contact with the birds can identify them by their call, markings on the beak or body profile during takeoff and flight.

Although judging a swan by its size is reliable, it may be difficult without a comparison nearby.

The trumpeter is considerably bigger than its smaller northern cousin, according to Rothe. The trumpeter swan, Cygnus buccinator, tips the scales at between 15 and 30 pounds, and boasts a wingspan of up to 8 feet.

The tundra swan, Cygnus columbianus, generally weighs between 13 and 18 pounds and has a 7-foot wing span.

As the ice age ended, the tundra swan evolved into a smaller, more compact bird capable of handling colder weather and longer journeys during migration, Rothe said.

The ancestors of the trumpeter decided not to fly across the ice, sticking to a warmer climate and evolving as a bigger bird that seeks a milder temperature for both summer and winter homes, he said.

Another reliable way to pin down the species of swan: The tundra swan sports a little yellow spot on its beak in front of its eye, Rothe said.

When the whistling swan flies, it holds its neck straight during the entire takeoff run and the initial flight, according to the Web site.

During its takeoff run and while becoming airborne, the trumpeter curves its neck into a shallow S shape.

For more information, check out www.trumpeterswansociety.org, which also offers satellite tracking of the birds.

Contact Dawn De Busk at 352-2252, or dawn.debusk@ frontiersman.com.