Monday, December 22, 2008
Mute Swans (Cygnus olor)
A native of northern and central Eurasia, the Mute Swan was introduced into North America to grace the ponds of parks and estates. Escaped individuals have established breeding populations in several areas, where their aggressive behavior threatens native waterfowl.
These swans are very large, all white with an orange bill and black face. Their wingspan can cover up to 94 inches. Sexes look alike, with males slightly larger and with larger knob on bill.
They are not mute like their name suggests but their calls are quiet and do not carry. They make a snorting "heorrr" and ca hiss aggressively. Wings make singing noise in flight.
As an introduced species it is of concern because of its effects on native wildlife. Its aggressive nature can disrupt the nesting of native waterfowl. It is protected in some states, but not others. Some states are attempting to control Mute Swan numbers.
Some cool facts about Mute Swans:
Downy young Mute Swans (called cygnets) come in two color morphs: a gray form and a white form. The gray (or "Royal") chicks start off with gray down and grow in gray-brown and white feathers, giving them a mottled look. White (or "Polish") chicks have all white down and juvenile feathers. Adults of the white morph may have pink or gray legs and feet instead of black, but otherwise the adults look alike.
The Mute Swan is reported to mate for life. However, changing of mates does occur infrequently, and swans will remate if their partner dies. If a male loses his mate and pairs with a young female, she joins him on his territory. If he mates with an older female, they go to hers. If a female loses her mate, she remates quickly and usually chooses a younger male.
The black knob at the base of the male Mute Swan's bill swells during the breeding season and becomes noticeably larger than the females. The rest of the year the difference between the sexes is not obvious.
The information above if from the Cornell Lab of Ornithology.