... and weighed up to 1,323lbs with a HUGE head more than 1.5 feet long — but its brain was squeezed for space

• Experts studied fossils of 'mihirungs', the name given to Australia's giant birds
• The largest, Dromornis stirtoni, was able to reach some 10 feet (3 metres) tall
• Using CT scans, the team calculated and compared various bird's brain sizes
• Mihirungs evolved larger and smaller brains in tandem with climate and food

Talk about being 'bird brained'! The largest ever flightless bird had a head some 1.6 feet (0.5 metres) long, but its extreme bill muscles left precious room for its brain.

This is the conclusion of researchers from Australia, who studied fossils of Dromornis stirtoni, a bird which grew to 10 feet (3 m) tall and weighed up to 1,323 lbs (600 kg).

D. stirtoni was the largest of Australia's 'mihirungs' — an Aboriginal word that translates to 'giant bird' — which went extinct around 50,000 years ago.