Trumpeter
swans establish life-long mates at approximately 3 years
of age and nest the following year. Sometime between late
March and early May, they build their nests, choosing
locations close to the water, either on shore, small islands,
or muskrat and beaver lodges. The male (called a cob)
gathers nest material, uprooting marsh plants such as
cattails, sedges, bulrushes, and horsetail, and brings
them to the female (called a pen) for placement. The nest
mound, which takes about 2 weeks to build, reaches a diameter
of 6 to 12 feet and an average height of 18 inches. The
same nest site may be used for several years.
Trumpeter
swans grow rapidly. By 8 to 10 weeks of age, young trumpeters
have reached half their adult size and are fully feathered.
They retain their gray juvenile plumage until the second
winter.
