For today’s Waterfowl Wednesday I decided to take break from ducks and talk about Mute Swans. Mute Swans are actually non-native to North America and considered by many as an “invasive” species.
Mute Swan (Cygnus olor)
Mute Swans are very conspicuous. They are entirely white; with large, heavy bodies and short legs. They usually hold their long, slender necks in an “S”-shape. Mute Swans have orange bills with a black base. Cygnets (young swans) have dusky brown plumage with a gray-black bill.
Mute Swans are not native to North America, they are from Europe and Asia. They were introduced by Europeans in the late 19th century as an ornamental addition to estates and parks. A feral population formed and has spread throughout the Northeast,Great Lakes, and Pacific Northwest regions of the county.
Both fresh and saltwater ponds, lakes, lagoons, and bays. May closely associate with humans.
Mainly aquatic vegetation, but also grasses, insects, small fish, snails, and frogs. They forage by dabbling, where they will submerge all their body except for their tail to reach food. They have huge appetites: Mute Swans can eat up to 8 pounds a day in aquatic vegetation. Many scientists consider them a nuisance because their enormous appetites put them in competition for food against native species and can degrade the environment.
Mute Swans form pairs around the age of 2, and mate with the same partner for life. Courtship behavior includes facing each other which moving their heads in unison. When arriving at the breeding site, they will slapping their feet again the water to ward away intruders and announce their presence. Pairs will usually use the same nest site each year. Mute Swans are very territorial of their nest site. Their threat display is to arch their wings over their backs and fluff out their feathers.
Mute Swans have 1 brood per year with 5-7 eggs in a clutch, sometimes up to 10. The female will mainly incubate the eggs for about 36 days. The male will incubate the eggs while the female is out foraging. The pair’s nest is found on the shoreline in a small mound of plant material. Once the eggs hatch, both parents will tend to the cygnets, who they will usually carry on their backs. Mute cygnets come in one of two morphs (plumage variations): gray or white. The cygnets will fledge after 4-5 months, but usually remain with their family through the first winter.
Mute Swans are not actually mute, but they are quieter than North America’s native swans. Their voice is hoarse, and have a variety of calls; such as hissing, grunting, or a “bugle” sounding call. Their wingbeats are so loud that they can be heard from a mile away.
Mute Swan populations can have a negative impact on native species, such as Black Skimmers, Black Terns, and Least Terns. Due to their “invasive” nature, there have been efforts by habitat managers to control feral swan populations. In 2005, the Department of the Interior officially named them non-native and stripping them of their protection from the Migratory Bird Treaty Act, although some local state laws protect them. Despite the controversial efforts, populations have been increasing over the years.
- Use caution when around Mute Swans, especially if you are nearby their nesting area or cygnets. They can be very aggressive and have been known to attack kayakers, canoes, and pedestrians who they feel are too close.
- The two native North American swan species are the Tundra Swan and the Trumpeter Swan.
- It’s very difficult to tell the difference between a male and female, but during breeding season the black base of the male’s bill will swell up to be larger than the female’s.