Some of the native predators found in Australia are the wedge-tailed eagle, Tasmanian devil, saltwater or estuarine crocodile, freshwater crocodile, goanna, funnel-web spider, great white shark, taipan, copperhead, red bellied black snake, brown snake, quoll and the dingo (not truly native as it did not originate on the continent).
Introduced predators include foxes, dogs, cats, feral pigs and cane toads.
Australia is ideal for the platypus because there are few natural predators. Apart from pythons, most predators of the platypus are introduced species.
The predators of true possums, which live in Australia, are eagles, hawks, owls and quolls. Foxes, which have been introduced to Australia, are also predators of possums. Possums should not be confused with opossums, which live in North America, and are not related to possums.
we would have to many animals in the country
The top native predators in Australia are the Wedge-tailed eagle, the Tasmanian devil and the various species of quolls. The dingo is a top predator also, but it is a relative newcomer, having been brought to Australia by the Aborigines several thousand years ago.
They have few predators and lots of food in Australia. They also breed at a faster rate than the native doves of Australia.
One of the reasons why platypuses are found only in Australia is likely to be because of the lack of predators in Australia. Introduced predators such as foxes and environmental changes brought by Man have caused more damage to the platypus population than the few native predators. With the exception of Antarctica, which remains largely uninhabitable, Australia was the last continent to be settled by Europeans, so the platypus has been able to thrive here.
Dingoes are at the top of the food chain. They have no natural predators in Australia.
The Phalangae Pordigose
If, by "parakeets" (a term not used in Australia) you mean budgerigars, then any of the larger birds of prey such as falcons, hawks and owls are their natural predators, along with quolls which are carnivorous, nocturnal marsupials that hunt in trees. Predators not native to Australia include feral cats.
Bobcats, Mountain Lions and Humans are some predators
Some predators of rabbits are bobcats, chetahs, hawks, snakes, lions, tigers, and bears. those are the predators of rabbits.
Some of them can fool predators with camoflage.