Mute Swan – Cygnus Olor
General: The Mute Swan was introduced to the United States in the late 19th century (1), primarily for its ornamental value. Like many such actions, it has manifested into unintended consequences and has become viewed by many as an invasive species due to its increasing population and aggressive behavior. Mute Swans have affected not only native bird species by displacing them but also aquatic animals due to their feeding on large amounts of aquatic vegetation used by fish and invertebrates.
Growing up on Long Island, NY, I had plenty of opportunities to view these birds. They can be very aggressive – I have watched Mute Swans chase dogs, geese and people not only from their nests but just because their “space” was invaded. These are easy birds to observe since they are use to people – yet they need their space. Even if you are motionless a bird that approaches should be treated with a lot of respect.
The male Mute Swan is known as a “cob” while the female is known as a “pen”.
Mute swans become sexually mature when they are two years old, but often will not begin breeding until they are three, four, or even five years old.
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. (3)
In spring Mute Swans build nests that look like large mounds with waterside vegetation. Female Mute Swans lay an average of 6 off-white to pale green eggs but can produce as many as 11 (2). Incubation takes about 35 days. The hatchlings are called “cygnets”. Within a few days they leave the nest and are able to feed themselves. They stay with the parents for a few months. Cygnets can fly at about 4-5 months of age and are considered “juveniles” at that time.
Identification: Mute Swans are unmistakable; there is really no bird in the eastern US that look like it. They are the largest birds on the water measuring 50”–60” long with a wingspan that is between 80”-94” long (over 7’). They are also heavy weighing between 12 – 30 lbs. The coloration of a mature bird is all-white with an orange bill (with some scant black markings) and a black front to their face. Their legs are black. They have a black “knob” on the top of their bill.
Immature mute swans can be dirty gray or white. Their legs are gray to pink. The bill is gray or tan
Habitat: Lakes, Ponds, shallow coastal ponds, estuaries, ponds, bogs, and streams flowing into lakes.
Territory: The natural range of the Mute Swan is in temperate areas of Europe across western Asia.
Migration: In its natural range, Mute Swans do migrate to a point.
Food: Mute Swans feed on a wide range of vegetation, both submerged aquatic plants and grasses and grains such as wheat.
(1) Audubon Society Field Guide to North American Birds