Intelligent crows can recognise human voices

By Jenna Hanson 16 May 2012
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Crows are known for their craftiness, but new research into voice recognition shows just how intelligent they are.

CARRION CROWS CAN DIFFERENTIATE between familiar and unfamiliar humans solely by the sound of their voice, according to a new study.

Crows have long been considered crafty, but the new research out of Europe confirms their intelligence, at least in discerning friend from foe.

Scientists played a random selection of familiar and unfamiliar voices saying “hey” to a group of carrion crows (Corvus corone corone) and found that the birds reacted more strongly to the voices of unfamiliar humans – whom they likely see as a potential threat.

When it came to another bird species, however, the crows tuned in more to the familiar calls. Researchers found that crows had a stronger response to jackdaws (Corvus monedula), which shared the same aviaries than those that were unfamiliar to them.

Researcher Claudia Wascher from the University of Vienna, says the results fit in well with what is already known about crows. “Crows have shown remarkable cognitive skills, which are expected to have evolved because of the requirements of living in complex social groups,” she says.

Crows eavesdropping on other species

Crows and other corvid species have recently become known for their cooperative and competitive skills with members of their own species, Claudia says, but the interaction between crows and other species is just as fascinating.

According to behavioural ecologist Rob Magrath from the Australian National University, many animals warn members of their own species about the presence of predators, and often, individuals of other species will “eavesdrop on these calls and so get ‘free’ information about danger.”

“The current research is interesting because it suggests that animals can even recognise the voices of individual members of other species [which] might be helpful in giving extra information, such as whether that individual is a friend or foe, or whether another individual’s alarm call is likely to be reliable or unreliable,” says Rob. 

“But [the research is] carried out on aviary birds [and] it is important to look at wild birds, to work out exactly what benefits animals get from recognising individuals of other species.”

The human-crow relationship

The new research, published in the journal Animal Cognition, confirms just how intelligent crows are.

“The fact that crows can recognise familiar humans is something which most people who know crows would have observed at some point,” says Claudia.

But the relationship between humans and crows is typically a tense one, with crows being considered a pest in many regions of the world. This dislike of crows may have sped up the development of the bird’s ability to recognise “dangerous” humans, says Claudia.

Crows as intelligent as chimpanzees?

Behavioural ecologist Darryl Jones and his PhD student Matthew Brown from Griffith University believe that crows possess intelligence comparable to that of chimpanzees, with the added benefit of having a completely different brain structure to mammals.

“Understanding what kind of clever behaviours crows are capable of could (and indeed already has) completely change our view of how brains work,” says Darryl.

They also say the study shows these crows are not only recognising familiar calls but also using this recognition together with knowledge of other species to determine how to react.
“This study also comes just over a year after the Americans discovered crows are able to recognise and remember individual human faces,” says Matthew. “Next time you see a crow, try to remember its face and its voice, because it will probably be able to remember yours.”