I get how crows might quickly learn to do this for a reward, but I don't understand how they initiated the process of teaching them. How did they get the first crow to do it for the first time, in order to learn there was a reward?
Swedish firm deploys crows to pick up cigarette butts
Clever corvids become newest weapon in Södertälje’s war against street litter
www.theguardian.com
“It would be interesting to see if this could work in other environments as well. Also from the perspective that we can teach crows to pick up cigarette butts but we can’t teach people not to throw them on the ground. That’s an interesting thought,” he said.