Crows found able to distinguish between human voices

May 16, 2012 by Bob Yirka report
Corvus brachyrhynchos or Corvus caurinus. Image: Wikipedia.

(Phys.org) -- Researchers at the University of Vienna have discovered that carrion crows are able to distinguish between familiar and unknown human voices. They also found, as they write in their paper published in the journal Animal Cognition, that the birds are able to do the same with other birds outside of their species, though they react in different ways.

Suspecting that crows, which are among the smartest of all , are able to tell the difference between people they know and those they don’t based on voice alone, the team set up an experiment to find out. They recorded the voices of five people who care for a group of carrion crows living in the university’s aviary, speaking the word “hey.” They then recorded the voices of five other people who the birds had never heard, speaking the same word. Later, when the recordings were played back for the birds, the researchers noted that the crows responded much more clearly to the unfamiliar voices, turning to look right away, investigating its source. The team suggests this is because crows see humans as a potential threat and thus any voice they hear that they can’t identify needs to be paid special attention.

Wondering if the birds displayed similar tendencies when interacting with other animals besides humans, the team repeated the experiment using bird calls instead of human voices. Because carrion crows tend to live and interact with other birds in the crow family, the team recorded calls from jackdaws and magpies, both of which are also considered highly intelligent. This time, when they played back the recordings for the carrion crows, they got the opposite reaction. The birds responded more clearly to the calls of other birds that they’d heard many times as opposed to calls from birds they’d never heard before. In this instance, the researchers suggest that the carrion crows on occasion team up with other such birds in cooperative efforts to find food or sound the alarm when threats are identified. This confirms prior work by other groups that had found that corvids (birds in the crow family) tend to work purposely with some birds when foraging, while ignoring others.

The team suggests that the behaviors exhibited by the carrion crows in the experiments likely help crows survive in both their natural environment and in those they share with human beings.

Explore further: Orchid named after UC Riverside researcher

More information: You sound familiar: carrion crows can differentiate between the calls of known and unknown heterospecifics, Animal Cognition, 2012, DOI: 10.1007/s10071-012-0508-8

Abstract
In group-living animals, it is adaptive to recognize conspecifics on the basis of familiarity or group membership as it allows association with preferred social partners and avoidance of competitors. However, animals do not only associate with conspecifics but also with heterospecifics, for example in mixed-species flocks. Consequently, between-species recognition, based either on familiarity or even individual recognition, is likely to be beneficial. The extent to which animals can distinguish between familiar and unfamiliar heterospecifics is currently unclear. In the present study, we investigated the ability of eight carrion crows to differentiate between the voices and calls of familiar and unfamiliar humans and jackdaws. The crows responded significantly more often to unfamiliar than familiar human playbacks and, conversely, responded more to familiar than unfamiliar jackdaw calls. Our results provide the first evidence that birds can discriminate between familiar and unfamiliar heterospecific individuals using auditory stimuli.

Related Stories

Crows are capable of distinguishing symbols, study finds

Oct 10, 2011

(PhysOrg.com) -- A new study published in Animal Behavior shows that crows are capable of recognizing symbols designed to represent different quantities and is one of many different studies currently lookin ...

Not so bird-brained: Clever crows recognise faces

Jun 29, 2011

Humans who dismiss birds as featherweights may revise their opinion when learning of crows which not only can identify the face of someone who is a danger but also teach others about the threat.

Crows demonstrate their cleverness with tools (w/ Video)

Apr 22, 2010

(PhysOrg.com) -- New Zealand scientists studying New Caledonian crows have found they can use three different tools in succession to gain a food treat. The crows are known to solve problems and fashion and ...

Crows show advanced learning abilities

Dec 14, 2011

New Caledonian crows have, in the past, distinguished themselves with their advanced tool using abilities. A team of researchers from the University of Auckland and the University of Cambridge have now shown ...

Recommended for you

Male monkey filmed caring for dying mate (w/ Video)

18 hours ago

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Orchid named after UC Riverside researcher

Apr 17, 2014

One day about eight years ago, Katia Silvera, a postdoctoral scholar at the University of California, Riverside, and her father were on a field trip in a mountainous area in central Panama when they stumbled ...

In sex-reversed cave insects, females have the penises

Apr 17, 2014

Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but re ...

Fear of the cuckoo mafia

Apr 17, 2014

If a restaurant owner fails to pay the protection money demanded of him, he can expect his premises to be trashed. Warnings like these are seldom required, however, as fear of the consequences is enough to ...

User comments : 5

Adjust slider to filter visible comments by rank

Display comments: newest first

Telekinetic
5 / 5 (3) May 16, 2012
" Our results provide the first evidence that birds can discriminate between familiar and unfamiliar heterospecific individuals using auditory stimuli."- article
The first?
tadchem
5 / 5 (2) May 16, 2012
Crows are highly vocal birds. Anyone who listens to them regularly can notice that their individual voices are distinguishable. There is no reason to assume that they cannot distinguish each other's voices and recognize each other, nor is there reason to assume they could not apply this talent to the recognition of *human* voices.
ddietle
5 / 5 (1) May 16, 2012
I have done a ton of research about crows (I wrote a very well-received article for Cracked.com about them) and I think this is just more fuel to the fire that when it comes to Earth-bound intelligence, it goes human, then crow, the the others.

And we should watch ourselves because crows didn't have to invent airplanes to fly.
TopherTO
5 / 5 (2) May 16, 2012
An excellent similar examination of crows found they can also differentiate human faces as well. A test was conducted whereby people put on a mask with very distinguishing facial features, somewhat similar to a Neanderthal face.

The masked person would then walk into a courtyard and climb a tree known to have a crow's nest. The crows immediately began their defensive calls, swooping in and out etc. They later had the masked person walk along the same path in the courtyard in the direction of the tree. The crows immediately distinguished the person as a threat and well before the masked person was close to the tree, would start to fend them off swooping and making warning calls.

The test was reiterated when the same person, but with no mask in same clothes, walked on the same path in the courtyard. The crows did not react at all, hence proving they identified the human threat based on facial characteristics.

see The Nature of Things with David Suzuki (CBC - Canada)
Isaacsname
5 / 5 (2) May 16, 2012
Why yes, yes they do :)

Other Corvids do as well, at least the ones I play with :P

@ ddietle, thanks for the article you wrote, I read it when it was published.

You should check out the Grove Park Inn in Asheville, it's one of the few areas where they are protected, at least locally.

Quite a sight to see when they know nobody will mess with them.

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Male monkey filmed caring for dying mate (w/ Video)

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Impact glass stores biodata for millions of years

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...