Odd Behavior: Young Ravens Don
There’s been some unusual gang activity among juveniles in North Whales recently. Not human teenagers, but rather youngsters of the common raven variety. The bizarre behavior has to do with how they find their dinner.
Typically, young birds search for food on their own. When one finds a meal—an animal carcass—it recruits its peers to help fend off the breeding pair whose territory the carcass is on.
But the kids don’t always scavenge this way. Researchers observed birds at a roost in Angsley foraging in groups, not alone. Such cooperation hasn’t been seen in common ravens before.
To figure out why the birds might use this alternate foraging tactic, scientists, led by Sasha Dall at the University of Exeter, built a mathematical model based on models of game theory—a mathematical technique used to identify the most profitable behaviors in a given situation (economists commonly use game theory models to analyze financial trends).
What they found is that gang foraging should occur when going it alone isn’t more efficient than working with others. That may be the case when there’s plenty of food available, as it is in Anglesey, an agricultural area where there are a greater number of carcasses than in the wilderness. And cooperative foraging might have social advantages: dominant males able to exclude subordinate peers from the carcasses may gain status and be more attractive to potential mates.
The study was published today in the journal PLoS One.