They are two of Sydney's great urban wildlife success stories. The Australian white ibis and the grey-headed flying fox, a type of large bat, are among the most commonly seen animals in the parks, gardens and suburbs of the harbour city.
The long-running drought in eastern Australia and loss of natural habitat has propelled both species to seek refuge among the bright lights of the big city.
But increasingly, the two are coming into conflict with each other and with humans. In places, the ibises - large black and white birds with bare, scruffy necks and heads - have become so numerous that they are threatening the survival of the flying foxes.
The birds and bats tend to roost in the same large, mature trees, where the birds' droppings are so toxic that they destroy the foliage and expose the flying foxes to too much heat and sunshine.
The latest battleground in the struggle between the two species is Cabramatta, a Sydney suburb. The local council has spent A$50,000 ($286,500) trying to eradicate the hundreds of ibises that have taken over a three-hectare patch of natural bush land in the middle of the urban sprawl.
Council officers have tried trapping the birds, removing their chicks and disturbing their nests, but each time the ibises have bounced back.
There are so many birds that the ground beneath the trees in which they roost looks like 'a white Christmas', according to Julie Spence, from the Cabramatta Creek Flying-Fox Committee.
