Life of an Alberta Trumpeter Swan
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In February, Alberta Trumpeters leave Tri-state wintering grounds in Montana, Idaho, and Wyoming. The Trumpeters migrate along a narrow corridor through southwestern Alberta, probably following available open water, and they arrive in the Pincher/Cardston area of southwestern Alberta starting in mid-March. Peaking in mid-April, they move on to the Calgary area. Then they arrive at Grande Prairie staging lakes, peak arrival in late April. Some then stay there while others continue to their breeding grounds further north in Alberta or in neighbouring jurisdictions.
Grande Prairie swans begin to arrive, usually while lakes are still frozen. They are often seen resting in puddles or flooded farm fields, which are vital habitat for the short time until the lakes begin to open. This is a rare chance to observe then at fairly close range. Please do not disturb them.
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As the ice begins to melt, the swans are free to disperse to the lakes for the summer. Young, single birds will hang out together all season in groups on lakes not used by paired and breeding swans. Trumpeters may choose a mate in the second year, but nest only when the female is from 3 to 5 years old. Older pairs will return to their lakes and renew their former nests year after year, while young pairs must find their own nesting lakes. Usually only one pair occupies a 324-hectare (800-acre) lake. They are very protective of their territory and will drive off other swans and often Canada Geese. When choosing a place to build a nest and raise a family, a trumpeter pair will select a lake that will be a safe place to raise young. It must also have an abundant food supply. They look for a quiet lake with a steady water level and little wave action. They may even choose a large beaver pond. For protection, the open water will be surrounded by sedges, cattails, and willows, providing privacy and a place to hide. The nest site itself is typically surrounded by water from 10 cm to several metres deep among this vegetation, near the edge of the open water.
The lake must have abundant food within reach. Trumpeters feed on the leaves of plants that emerge from the water, especially pond weed and sedges, but also on roots and tubers below the surface at a depth of up to one metre.
Once the lake has been selected, construction of a nest platform begins soon after the swans arrive in spring, often before the lake is completely free of ice. Muskrat and beaver houses or beaver dams are often used as a base for nests. The nests measure from 1.8 to 2.4 metres (6 to 8 feet) across.
Starting about the first week in May, the pen lays one egg every other day. Numbers vary, but on average she lays 5 or 6 . They are off-white in colour, and approximately 10.9 cm by 7.4 cm (4.3 by 2.9 inches) in size, and weigh about 198 grams (7 ounces). The shell is 6.3 mm (1/4 inch) thick. The pen incubates the eggs for 33 to 35 days, while the cob swims close by, alert to predators. The average hatching date in the Grande Prairie area is June 10th.
Cygnet hatch weight averages 210 grams (7.4 pounds). They are covered with grey down. Within two days, the tiny birds tumble out of the nest and can swim and feed themselves. For the first 2 to 3 weeks they eat snails, shrimp and small water insects found on the surface of the water. Later their food is almost entirely plants that float to the surface when broken loose from the lake bottom by the parents.
The first few weeks of a cygnet's life is not without hazards. Cold, wet weather in the cygnets’ first weeks of life may cause death, but they can also be trampled by the parent’s large feet, or become entangled in water plants and drown. Other hazards are disease spread by parasites, and leeches that get in their nostrils and suffocate them. They can get tape worms from snails they eat, or be attacked by other birds or animals. In this area an average of 3 or 4 of each clutch survive, though families of 7 are known; one brood of 8 grew up on a lake near Grande Prairie in 2002.
First feathers appear in 4-6 weeks. By 10 weeks cygnets are fully feathered in brownish-grey, and stay grey until their second year. Feet are yellowish or olive-grey, and bills are somewhat black with the portion behind the nostril pink or coral colour. By mid-September they have reached a weight of up to 10 kg (22 pounds). Cygnets learn to fly in 91 to 122 days.
Trumpeter families will stay on their breeding lakes and marshes as long as possible to allow the cygnets to gain the weight, strength, and flying skills needed to migrate successfully to the wintering grounds. In mid-September, as the cygnets improve their flying skills, the close-knit family will congregate with others in large groups on larger staging lakes, where they may be joined by tundra swans already migrating south from the Arctic. The tundra swans and non-breeding trumpeter swans tend to depart on the southerly migration first. Then in late October or even early November, when lakes are almost frozen over and just before the first major storm, the small family groups and will leave, marking the arrival of winter in Alberta.
Alberta’s trumpeter swans spend winter in the United States in the western portion of the Greater Yellowstone Ecosystem - the Tri-State area of Montana, Idaho, and Wyoming - a distance of about 1,360 km (850 miles) from Grande Prairie.
There the altitude is higher, the snow deeper, and the cold often more intense than in Alberta, but warmer springs keep lakes and streams open. Swans need open water to feed on aquatic vegetation.