BIZARRELY coloured blue and yellow cockatoos have been spotted flying around the east, bewildering bird experts and the residents who discovered them.

While regular sulphur-crested cockatoos are a common sight in the area, the coloured variety feature bright blue and yellow feathers, and sometimes blue feet.

Vaucluse resident Ben Mohat sent the Wentworth Courier photographs of the multicoloured birds after his son Reeve found them at Lyne Park, Rose Bay, last week.

media_camera Up close look at the cockatoo found at Lyne Park. media_camera Another blue cockatoo photographed by Diane Davie.

Mr Mohat said Reeve also saw some green, pink and even mixed-coloured birds.

“We go down to the park almost every day and it was the first time we had seen them walking and flying around,” Mr Mohat said.

“We’ve never seen cockatoos like this and I can’t imagine how they could have been coloured like this.”

Bird rescuer Josh Cook said the colouring was unnatural but did not believe the cockatoos were being captured and painted.

“Even for an experienced bird handler it would be hard to catch a cockatoo, let alone try to paint it without it taking your finger off,” he said.

“It’s a lot of effort to be doing something so cruel. But there are a number of ways the colouring could be happening.”

media_camera A fluoro yellow cockatoo photographed near Dunbar House.

Mr Cook said the birds could be eating something containing dye or nesting near a coloured substance.

“The colour looks like it’s coming out of the feather and is in their skin, so they could be eating or drinking something with a blue stain in it,” he said.

“But they would have to be doing it all the time to have such an impact.

“Even when you dye a bird or chicken, you have to wash them in a special detergent so the dye can be absorbed into the feather.

“They could also be nesting near an industrial site and coming into contact with a blue oxide or dust. It would be worth monitoring the birds’ movements to see how this is happening.”

media_camera Some of the cockatoos have more than one colour blended through their feathers. media_camera The cockatoos are colourful but it’s a mystery as to why or how they have managed it.

After looking at images of the birds, a birdhandler at Taronga Zoo ruled out the change as a mutation.

“The colour on these Sulphur-crested cockatoos is not a natural mutation and that they may have come into contact with some kind of coloured material or dye,” a spokeswoman said.