Black Swan
|
|
Scientific Name: Cygnus atratus |
| Geographical Range: |
|
| Habitat: Around lakes and rivers, preferably swamplands and open waterways, which can be fresh, brackish, or salt water |
|
| Diet in the Wild: Aquatic vegetation and tidal grasses and grains |
|
| Conservation Status: Common |
|
| Location in the Zoo: Next to the Zoo Creek Café |
|
| |
|
| Physical Description: ”Atratus” translates into “dressed in black.” Therefore, the body plumage of the black swan is black with white distal secondary and primary feathers on the wings that can be seen only when the bird is in flight. The feathers turn curly on the swan’s back. The swan’s bill is bright orange-red with a white band near the tip. It also has bright red eyes. Its legs and webbed feet are black. The black swan is the largest of all waterfowl, as it grows to be up to five feet long with a wingspan of up to six feet. The male swan – cob – is much larger than the female – pen. The young swans –cygnets – are fluffy and usually a grayish color until they mature. |
Social Organization: The Black Swan is the most social and least territorial of all swans. The non-migratory birds often nest in rather loose colonies. Both the cob and pen also take part in parenting. The cygnets stay with the family unit for about nine months to a year, even though they can fly after about two months. |
| Special Adaptations: The Black Swan has from 22 to 25 vertebrae in its elongated neck that allows it to simply duck its head under the water to reach deep aquatic vegetation. The beak of the swan also has grooves that aid in the feeding process because they make grabbing food much easier. Protection of the clutch – nesting eggs – is also very important to the family-oriented birds. The pen begins molting during clutch protection and does not regain flight until the cob begins to molt. This ensures that the clutch is protected by at least one grounded parent at all times, since there is not a time when both parents can take flight. Such adaptations are about all the swans need for survival, as they have no natural predators. |
|
| Reproductive Behavior: One thing that sets the Black Swan apart from most animal life is its mating patterns. Black Swans begin their lifelong partnership shortly after they become a year old. The birds can live up to 40 years and will only mate with their original partner. Black Swans usually court for up to two years before they begin breeding. The lovebirds build their nests together from grass, roots, and small sticks. The pen wriggles and sits in the nest to make grooves for the eggs to be laid into. The pen then lays four to eight pale green eggs one day apart. Incubation begins after the last egg has been lain and lasts from 35 to 40 days, and the cob even takes turns in the nest. After about 24 hours post-hatching, the cygnets are taken out to the water to swim with the parents. Even weeks after the cygnets are hatched, they ride on the back between the wings of their parents while they swim. The cygnets will remain with the family unit until the next breeding season, which could be up to a year. |
The Animal at the Zoo: The Fort Worth Zoo has two absolutely lovely Black Swans on display. The swans swim with an arched neck and raised elbows, which creates the classic swan look. The two birds are particularly enjoyable to watch, as they are both so tame and serene. Not much of their behavior – other than feeding, which takes part at dusk – can be observed in captivity as it could be in the wild. |
|
|
Page Author: Marc Nettles manettles@mail.txwes.edu Sources and Links: http://www.scz.org/animals/s/bswan.html |
