Thousands of green budgies have been spotted flying en masse over grazing land in north-west Queensland, with several local residents taking to their phones in a bid to capture the noisy and spectacular sight.

Key points: Wild budgies flock after the rain to socialise, court and find food, an expert says

Wild budgies flock after the rain to socialise, court and find food, an expert says Cloncurry local Paula Booth says she hasn't seen a flock this big in 20 years

Cloncurry local Paula Booth says she hasn't seen a flock this big in 20 years Wild budgies are much lighter than their caged cousins

Cloncurry resident Paula Booth said she had not seen such a large volume of wild budgies in 20 years.

"I remember seeing them a long while ago in the Cloncurry River to have a drink, but not in these numbers," she said.

Motorists have reported seeing budgie flocks following trucks and road trains along open roads.

Bob Donely, an avian expert at the University of Queensland, said budgerigars do this because they are used to seeing grain trucks.

"Grain trucks often have spillages behind them and the budgies can often pick that up," he said.

Professor Donely said wild budgies evolved in the heat and in areas that have no food.

Wild birds 'not the same as pets'

Recent light rain in the state's north west had brought larger groups of birds to grazing land.

The often loud and spectacular cloud of green and gold birds is called a murmuration, which occurs after rain so the birds can socialise, court and move to find food sources.

Professor Donely said people's fascination with the wild flocks was because budgies were the most common pet bird in the world.

Commonly known as bush budgies, the wild flocks differ from the birds that become household pets.

"A bush budgie will usually weigh 25 grams — a pet budgie typically weights 35 to 40 grams, and a show budgie may be as heavy as 60 grams," Professor Donely said.

"The photos online of the thousands of budgies have me drooling with envy, would love to be out there."