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February 25, 2009

Don't mess with this gang (of birds)

Posted: 10:53 AM ET
Common ravens, contrary to what was thought, sometimes forage in gangs.
Common ravens, contrary to what was thought, sometimes forage in gangs.

You may think of ravens as solitary creatures rapping at chamber doors, but new research shows that some of young ones form gangs when they look for meals, which consist of animal carcasses.

Gangs, in this context, mean groups of juvenile ravens that forage together and overwhelm the territorial adults defending the animal carcass, said researcher Sasha Dall of the University of Exeter in the United Kingdom, in an e-mail. In other words, the kids get together try to chase off the adults defending the food, which may influence their social standing among their peers.

This is the first time that flock foraging has been observed in common ravens, Dall said. In a typical raven roost, a bird attains dominance by finding a carcass alone.

"Since most birds will therefore have to suffer being bullied a lot, there is a strong advantage to doing things to avoid giving any one bird such finder advantages," Dall said. "Turns out foraging in gangs is one such tactic."

In fact, the birds' behavior can be explained by game theory, a branch of mathematics that looks at strategic interactions, Dall's research found. The ravens forage in gangs when searching for food alone is no more efficient than foraging with others, the model shows. It's unlikely that the birds are consciously making such calculations, however, and these responses are likely hard-wired, Dall said.

Any analogies to human behavior are limited, but the research does illustrate how food availability, environment, and other external factors can influence social advancement and the stability of groups, Dall said. Scientists believe human ancestors also faced problems of food scarcity, and one solution to surviving in particular environments is to pool the food-finding efforts. If the group solution works in particular circumstances, it's "nevermore" to individual foraging.

The research is published Wednesday in the journal PLoS One.

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Filed under: Animals • Birds


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Franko   February 25th, 2009 11:38 am ET

Crows do evict songbirds – bullies of the neighbourhood
Harass a hawk, just as do seagulls

Watch - Crow and Kitten are Friends


S Callahan   February 25th, 2009 11:39 am ET

boy someone hasn't read their Bible.....God has used Ravens to give a message several times......

I was hoping the Tech would have a comment section on the Alien life article....waiting.


Hypocritebuster   February 25th, 2009 12:05 pm ET

No big news to anybody who's seen Hitchcock's THE BIRDS. 🙂


birdwatcher   February 25th, 2009 3:34 pm ET

Bernd Heinrich talked about this in his book "Ravens in Winter" which was published in 1991. I haven't checked his research papers, but I'm sure he published about this well before now.


Christopher   February 25th, 2009 3:56 pm ET

The following sentence from the story seems to be the primary statement of the research findings, but I can not make sense of it. "The ravens forage in gangs when searching for food alone is no more efficient than foraging with others, the model shows."


LIP   February 25th, 2009 4:17 pm ET

Crows and Ravens both belong to the Genus Corvus and both behave similar in that dominent juvenils will call in others for a big feed to allow dominence by juvenils over adults, breaking down the normal pecking order found in family units. This is nothing new and has been observed for quite a while by those people interested in observing Crow and Raven behavior.
I have seen this many times in my neighborhood Crows in a country setting with both types of behavior exhibited.


DJ   February 25th, 2009 4:50 pm ET

Interesting research. An enjoyable article! Keep em coming.


birdistheword   February 25th, 2009 5:36 pm ET

'birdwatcher' has it right – this is old news. The mathematical model is perhaps a new twist, but the biological phenomenon has been recognised for years.


Franko   February 25th, 2009 6:31 pm ET

Ravens do not migrate, feathers ruffled, waiting for the next garbage dump feeding, survive the bitter cold - Not a birdbrain, but a winged pack animal ?


MrSatyre   February 25th, 2009 8:13 pm ET

This is news? Anyone who's had a bird feeder or two knows that birds of a feather flock together. Ravens, crows, starlings, even woodpeckers, they all arrive in gangs and pester the other breeds until they leave.


Jeff   February 25th, 2009 10:27 pm ET

I have seen juvenile Magpies displaying the same gang foraging behavior in my back yard here in Idaho. It's probably not as rare as one might think.


Ken in Dallas   February 26th, 2009 5:33 pm ET

Birds are a lot smarter than the researchers know how to measure. They have very direct minds that are capable of learning the relatively complex behavior of flight. This level of gaming is easily within a raven's learning capacity.

Callahan, what's mythology doing in a science blog? Besides reminding me to note that "creation science" is in no way scientific, that is.


Franko   February 27th, 2009 1:13 pm ET

God made Man, in His Mirror image - so when You look in a mirror, you see God - "Birds recognise their own reflection in the mirror as being themselves and not that of another bird" - Not just a ManGod, but also a BirdGod - will have to put a mirror in front of a Dog


Brown   March 3rd, 2009 8:56 pm ET

Gruesome, but weren't ravens used to by the guards in London Tower (UK) to peck out the eyes out of captives? The ones in London are enormous. Fleur


Damon Goodyear   March 4th, 2009 3:47 am ET

Surely 03/03/01 is the correct day. Division by 3 day. And 03 – 03 00 would subtraction day. Square Root day would be 03.03.09.

Tomorrow is an additional day. As is the day after tomorrow.


In home Personal training Long Island   December 5th, 2013 6:43 pm ET

I can see the headlines Breaking news Gang of Ravens steal food from family picnic! This proves birds are smarter than once thought. How do they decide which bird eats first from the gang.


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