Researchers who found that birds are hardwired to fear colour red believe that this may be true in humans as well.
Lead researcher Sarah Pryke of Macquarie University in Sydney conducted her study on Australian Gouldian finches (Erythrura gouldiae), who are genetically prone to develop either red or black heads.
The redheaded birds were aggressive, dominant and avoided by others.
The study showed that finches instinctively avoided red-coloured competitors.
Pryke examined the competition between young Gouldian finches, whose heads, yet to blossom into coloured adulthood, are all dull grey.
During the study, she raised finches that were genetically destined to be redheaded with black-headed parents and others that were genetically destined to be black-headed with red-headed parents.
And some of the finches were raised by parents of the same colour group.
The uncoloured juveniles were later allowed to mingle with adult red- and black-headed birds, or placed in isolation.
The researchers later randomly painted their heads red, black or a blue control colour.
Pryke left the pairs of hungry birds to fights over food and later looked at stress in individual birds by measuring blood levels of the hormone corticosterone.
The findings showed that red-painted juveniles emerged victorious 81.5pct of the time, regardless of what coloured head they would ultimately grow up to have.
They also showed 57.9pct increase in corticosterone levels.
These results are prompting the researchers to suspect that in other animals, including ourselves, red's aggressive and intimidating character might also be hard-wired into brains from birth.
"How the experimentally reddened finches won contests was interesting: their opponents simply moved out the way. It was not that the birds with fake red heads were suddenly more aggressive," Nature magazine quoted Pryke as saying.
"This suggests that Gouldian finches hatch 'knowing', as it were, that birds with red should be avoided," she added.