Black Swans (Cygnus atratus) breed mostly in south-eastern and south-western Australia. They are monogamous, with both parents sharing responsibility for incubating their eggs and raising their cygnets. Black Swans are herbivorous and eat a variety of aquatic plants as well as grazing on lawn grasses and pastures. A pair of Black Swans nested on the edge of an artificial lake in John Oldham Park in the centre of Perth, the capital city of Western Australia. Their huge nest was made of sedges that they had collected, and it proved very attractive to a variety of other waterbirds, particularly Eurasian Coots (Fulica atra), Dusky Moorhens (Gallinula tenebrosa) and Australasian Swamphens (Porphyrio melanotus). The Swan on the nest was irritated by the intruders, repeatedly lunging at them to drive them away. In one incident, the nesting Swan grabbed a Coot in its beak before tossing it off the nest. After more than half an hour spent repelling nest invaders, the Swan relaxed, and began dozing.