Crows are capable of recursion, scientists claim

Environmental “engineering” by ancestors of elephants is a possible factor that contributed to the environmental change that likely lead to the extinction of Gigantopithicus, the enormous, ancient ape.

"Crows demonstrate that crows are capable of recursion"

> Some scientists remain skeptical. Arnaud Rey, a senior researcher in psychology at the French National Center for Scientific Research, says the findings can still be interpreted from a simple associative learning standpoint—in which an animal learns to link one symbol to the next, such as connecting an open bracket with a closed one. A key reason, he explains, lies in a feature of the study design: the researchers placed a border around the closed brackets in their sets—which the authors note was required to help the animals define the order of the brackets. (The same bordered layout was used in the 2020 study.) For Rey, this is a crucial limitation of the study because the animals could have grasped that bordered symbols—which would always end up toward the end of a recursive sequence—were the ones rewarded, thus aiding them in simply learning the order in which open and closed brackets were displayed.

Doing this seems to make this more of a linear problem than a recursive problem. Place all the non-bordered symbols. Then place all the bordered symbols in reverse order of the non-bordered ones.

I feed the crows cashews as I walk the dog, and I find their behavior fascinating.

They "commute to work" each day. Crows all live in a community that they go home to each night, and then each morning they all come back to their specific areas, usually in pairs. If you're in a place where you see crows every day, it's almost certainly the same pair of crows you’re seeing each day.

Each pair has a strict territory. I don't know how it works in rural areas, but in my neighborhood the territories are demarcated by streets and cover one or two neighborhood blocks.

They definitely recognize me and follow me for the peanuts. Usually they'll follow me from one block to the next, and another pair will come up and chase them off.

They do seem to set aside their territorial fighting when there's a lot of food; a guy up the street from me throws ridiculous amounts of food onto his front lawn, like whole loaves of bread, to feed the birds (probably rats and coyotes too), and the crows all gather peacefully there every morning before heading back to their territories.

I would love to know how they determine who gets what territory. I assume it's handed down; every year there's a month or so when the adolescents come out (they're a little bit ganglier and pester their parents for food all the time rather than foraging for it themselves) so I think they're there to learn the ropes. Are there crow dynasties that have owned certain city blocks for generations? How long do they last?

Lots of interesting stuff to watch in the lives of crows.