In the past two weeks the ice melted off Goose Pond, and the swans began to return. Tundra swans migrate in massive flocks, and usually number in the hundreds on Goose Pond. Occasionally there are trumpeter swans on the pond, usually in pairs, or small family groups. An unusual sight this week, was an exotic mingling with the tundra swans on the pond. Richard Armstrong, a wildlife photographer and Madison Audubon supporter, was taking photos of the early migrants, when he noticed the tell-tale orange bill of the mute swan.
Besides the orange bill, mute swans can be distinguished from tundra swans and trumpeter swans by the black, fleshy knob at the top of the bill. They tend to be a little smaller than our native swans. They carry their necks in a distinctive “S” shape while swimming, usually with the bill pointed down.
The mute swan is native to Eurasia. It has been present in North America since the late 19th century when it was brought here to adorn ponds in urban parks. Some birds escaped or were released from captivity. The bird escaped and due to its long life and urban adaptability, quickly established a large and growing population. Estimates based on aerial surveys over the Great Lakes, and Christmas Bird Counts, show that the North American mute swan population, around 18,000 in 1997, increases by 10% every year. A mute swan may live up to 18 years in the wild, and produces a brood with an average of 5 cygnets.
Mute swans congregate in large flocks. They remain year-round in the coastal Great Lakes wetlands region where open water can be found even in winter. They are big eaters, consuming up to 8 pounds of aquatic vegetation a day. During spring when resources are most limited, mute swans can strip a pond of its vegetation beyond the ability to regenerate before our native waterfowl have even returned. Overgrazing is sped up by the bird’s habit of raking and paddling the substrate while feeding. Even vegetation that isn’t eaten is killed by this habit, and turbidity can increase enough to prevent regeneration. This puts pressure on diving ducks such as canvasbacks, and scaups that rely on the same aquatic vegetation.
Mute swans are exceptionally aggressive and territorial. They can displace other waterfowl including trumpeter swans from their nesting areas, and have been known to attack or even kill adult or juvenile ducks, geese, and other wetland birds. Trumpeter swans are still a species of concern though they were taken off the Wisconsin endangered species list in 2009. Mute swans are also known to attack humans. Mute swan-human interactions are more common because mute swans are often found in urban wetlands, and because their beauty and reputation as the symbol of love may fool people into believing they are gentle creatures. A few years ago, a man in Ohio ventured too close to a nesting pair, and was attacked by the cob (male); he suffered a heart attack and died. Do not be fooled, and remember to respect all wildlife!
Many states have a mute swan management plan with a goal of achieving zero reproduction within state boundaries. Wisconsin’s DNR adopted such a plan in 1997. The primary method used to reduce mute swan numbers was through egg addling. Within ten years, the Wisconsin mute swan flock was greatly reduced. Michigan’s DNR decided not to manage their mute swans, and they now have a population of 4,000-5,000. On occasion, small flocks of mute swans are found off the tip of Door County where Michigan swans move along the Grand Traverse Islands, connecting Michigan and Wisconsin. Mute swans are rare at Goose Pond, however, this spring, bird-watchers may be able to find the trifecta of swan species.
Written by Maddie Dumas, Goose Pond Land Steward & Mark and Sue Foote-Martin, Goose Pond Sanctuary Managers