Barbara and Peter Brown run sheep on their Nullarbor pastoral station, but lately their neighbours have started asking if they are running budgies instead.

Barbara Brown sent the ABC these pictures of the thousands of green budgerigars that have appeared at Arubiddy (an 800,000 acre station seven hours drive east of Kalgoorlie) in recent weeks.

"In September we started seeing small flocks of them, and gradually they have built up and up," Mrs Brown said.

"Last Monday they actually came into the homestead, and when that happened there was just plagues of them."

"By Tuesday the sky was grey with budgies."

"We were mustering the rams and it's a fairly big paddock and it was just full of budgies, as far as the eye could see."

Barbara Brown has lived at Arubiddy for 37 years, and says she's only seen flocks of budgies like this once before, in 1974.

"I brought my grandchildren out because I wanted them to see it."

"There are trees that are dead which are still standing, and you'd swear they are all alive."

"When you drive past, it's like those trees just become alive and take off. It's fascinating."

The Browns don't know what's caused this sudden appearance of the budgies, but they're hoping to follow the budgies to see where they go next.

"They're all identical green budgies and they all seem to be adult budgies as well."

"A couple of neighbours visited the other day and one said 'are you running sheep or budgies?'"

Although it's an amazing site, Mrs Brown says having thousands of birds on the property does have it's downside, not least the noise.

"It's very noisy. At night time it's really quite eerie. There's this hum."

"We have a dam that we use for the pigs and the budgies have drunk it dry, we've been pumping water in for them."

"We're finding them dead in the all the tanks, and having to scoop them out. That's the sad part."

"We have a lot of backpackers here and I said to a French boy the other day -take this in because I've only seen this once before in my lifetime."

Want to learn about life on the Nullarbor? Download the ABC Audio tour, Crossing the Nullarbor.