Since September, the São Paulo Zoo, in Brazil, has welcomed fifteen Black and Black-necked Swan cygnets. The snowy babies can be seen swimming alongside their graceful parents…or being chauffeured.
The Black Swan (Cygnus atratus) is a large species of swan, which breeds mainly in the southeast and southwest regions of Australia. The species was introduced to various countries as an ornamental bird in the 1800s.
The Black-necked Swan (Cygnus melancoryphus) is the largest waterfowl native to South America. However, they are the smallest member of their genus.
Black Swans are mostly black-feathered, with white flight feathers. Their bill is bright red and legs are greyish-black. An adult can measure between 110 to 142 cm (43 to 56 in.) in length and weigh 3.7 to 9 kg (8.2 to 19.8 lb.). Their wingspan is 1.6 to 2 meters (5.2 to 6.6 ft.).
Black-necked Swans have a black neck and head, greyish bill, and white body plumage. They have a red knob near the base of the bill and white stripe near the eye. In comparison to the adult Black Swans, the Black-necked species is slightly smaller. Adults average 102 to 124 cm (40 to 49 in.) and weigh 3.5 to 6.7 kg (7.7 to 14.8 lbs.) Their wingspan ranges from 135 to 177 cm (53 to 70 in.).
The Black Swan utters a musical, bugle-like sound and they are known to whistle when disturbed while breeding or nesting. Like the Mute Swan, the Black-necked Swan is relatively silent.
Both species are almost exclusively herbivorous. They feed in a similar manner to other swans, dipping their head and neck underwater.
Like other swans, the two species are largely monogamous, pairing for life. Their nest is a large mound of reeds, grass and weeds and is built in shallow water or on islands. It is reused every year and rebuilt as needed.
Both parents share the care of the nests, and a typical clutch of 4-8 eggs are incubated for 35 to 40 days. Both sexes participate in incubation. After hatching, the cygnets are tended-to by both parents and are fledged at about 9 months.
Cygnets may ride on the parent’s back for trips into deeper water, but Black Swans are less known for the behavior than Mute or Black-necked Swans.