Swift parrots are among the worlds fastest-declining parrots, breeding only in Tasmanian old-growth forest with welfare threats from habitat loss and introduced predators.
Nest predation by sugar gliders causes egg and chick loss with adults defending repeatedly failed nests. Logging of old-growth trees destroys nesting hollows that take centuries to develop. Rapid population decline means inbreeding stress is increasing. Birds that experience repeated nest failure suffer energetic costs with no reproductive benefit. Habitat fragmentation reduces access to flowering eucalypts the species depends on.