Trumpeter Swans












Natural History:

The Trumpeter Swan (Cygnus buccinator) is the largest native North American waterfowl species.  They can weigh up to 35 pounds, stand four feet tall, and have an impressive seven-foot wingspan.  The male (Cob) is larger than the female (Pen).  First year swans (Cygnet) are gray in color and will retain some gray feathers into their second year.

Trumpeter Swans can be found from Alaska, east to the Great Lakes, south to Arkansas and over to near the west coast.

Most Alaskan and Canadian flocks still migrate long distances while many U.S. flocks have become sedentary or only migrate short distances.  Many of the restoration flocks are migratory and are now mixing with sedentary flocks, establishing new migration routes.  Fall migration from breeding areas begins in October to late November to escape freezing waters.  Spring migration from wintering areas typically begins in March but is often weather dependent.

Trumpeter Swans will nest on a variety of freshwater wetlands, ponds, lakes and rivers.  These habitats provide not only forage for Trumpeters in the form of aquatic plants and invertebrates but also provide islands for nesting.  Islands are preferred over shoreline nest sites because of the added protection against predators.  Nest can also be built on muskrat and beaver houses, beaver dams, and floating platforms.  Nest building typically begins in late April to early May.  When all of the eggs have been laid (usual clutch size ranges from 4 to 6) the female will begin incubating, which can last as long as 33 days.  During this time the male will defend the nest against potential threats, including foxes, coyotes, and raccoons.  Once hatched, cygnets may go to the water within a few hours under the protection of the male.

The Decline and Current Threats

Once considered abundant and geographically widespread, Trumpeter Swan numbers and distribution were greatly reduced during the early fur trade and European settlement (1600s-1800s).  Swan skins and feathers were sold in the fur trade where they were used in popular products such as ladies’ powder puffs, fashionable hats, and ink pens.  In 1932, only 69 individuals were documented but it was unknown at the time that flocks inhabited parts of Alaska and Canada.  Since then, numbers have increased due to protection from shooting, habitat preservation, and restoration programs.  However, many threats to their recovery still exist including habitat loss, power line strikes, poaching and lack of migration in several wild and restored flocks.

What WWS is doing to restore the Rocky Mountain Population of Trumpeter Swans

The Trumpeter Swan Fund was established by WWS to aid in the restoration of Trumpeter Swan populations by supplementing wild populations with swans from it’s captive breeding program.  Release sites are in areas that once had healthy Trumpeter Swan populations and are still suitable for swans.  These sites are on the fringe of the current range and occupied habitat of wild swans.  Thanks to the generosity of private landowners, we now have eight captive breeding pairs in the Jackson, Wyoming area.  Most of the Trumpeter Swans in the program are birds that were salvaged and rehabilitated from power line strikes, lead poisoning, and other debilitating injuries but could not be released.  These eight pairs produce approximately 35 cygnets per year.  Beginning in 2011, our captive breeding flock will have increased to approximately 12 pairs that may produce 60 cygnets or more.

The Canadian Egg Collection Project was a 3-year collaborative effort between WWS, US Fish and Wildlife Service, the Canadian Wildlife Service and the Pacific Flyway Council.  This project was designed to address the lack of genetic diversity in the population due to the severe population decline and slow rebound in numbers.  These factors resulted in a “bottleneck” which results in closely related individuals breeding.  Canadian Trumpeters naturally migrate to the tri state area of Montana, Idaho and Wyoming for the winter.  However, pair formation typically does not occur until late March to mid-May.  Because tri-state flocks have become relatively sedentary, timing reduces natural pairing with migratory Canadian flocks.  This project introduced birds that will over time increase genetic diversity in the Rocky Mountain region making the population more robust.

Since 2007, WWS has collected 180 eggs (60/year) in Alberta and British Columbia.  These locations were chosen due to the high numbers of successfully producing Trumpeters in the area.  At least two viable eggs are left in the nest to be hatched and raised by the parents. The collected eggs are brought to Jackson, WY and incubated at a WWS facility.  Once hatched, the cygnets are moved to protected outside enclosures until the following summer when they will be released in restoration areas (see restoration areas and accomplishments).  Canadian Wildlife Service post monitoring surveys indicate that this project has caused no impact on Trumpeter Swan nesting numbers in the project area.

 

 

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