Cygnus atratus

Black swans are native to Australia, including Tasmania, and are concentrated particularly in southern Australian wetlands. Introduced populations occur in New Zealand, Europe, and North America. They inhabit lakes, rivers, and swamps containing fresh, brackish, or salt water and favor places with abundant aquatic vegetation. When aquatic food becomes limited, birds may move onto dry pasture or flooded farmland. Adults measure approximately 1.1 to 1.4 meters long, have wingspans of 160 to 200 centimeters, and weigh about 3.7 to 8.7 kilograms. (Animal Diversity Web)

These swans are chiefly herbivorous, reaching submerged foliage with their long necks and also grazing on land. Their foods include cattails, pondweeds, water milfoils, widgeon grasses, algae, and other vegetation, with insects consumed occasionally. Black swans maintain strong pair bonds, and both adults participate in nesting and cygnet care. They can breed repeatedly during a long season extending from February through September. Females lay five or six eggs, and incubation lasts approximately 35 to 48 days before the precocial cygnets emerge. (Animal Diversity Web)