Queen Elizabeth is required to send birthday letters to all centenarians and she takes that duty very seriously, as one Aussie cockatoo found out.

Bonorong Wildlife Sanctuary’s star inhabitant Fred the Cockatoo marked his 100th birthday on Saturday with a letter from the monarch herself.

• Royals defend apartment spending

Celebrating at the Hobart sanctuary, Fred shared his birthday with visiting admirers, who enjoyed face painting and a sausage sizzle.

The attention was well-deserved; it’s extremely rare for cockatoos to live to such a ripe age.

In the wild, most survive to the age of 40, while those in captivity usually live to the age of 70.

Fred’s keepers believe the friendly cockatoo could in fact be older than 100.

“We aren’t 100 per cent sure but we think that he is well past,” Greg Irons, Director of Bonorong Wildlife Sanctuary told the Daily Mail Australia.

“He was 95-years-old when I started working, which was 10 years ago – we just waited a bit longer to make sure he is past 100.”

“He doesn’t do a lot of flying, still dances, sings and talks a lot … he behaves like a two-year-old,” Mr Irons said.