Some birds are so clever and industrious that they’ve got quasi-jobs picking up after humans.

Now the six birds who have learned the rubbish-reward equation are tidying up the theme park, though the park is already quite clean. It’s really less about making the birds janitors than enlisting them as teachers, encouraging people not to litter.

A transaction like that is probably a no-brainer for these smart crow relatives, which range through Europe and Asia.

“Birds have evolved a level of cognition that we’re just beginning to understand,” says Don Moore, director of the Oregon Zoo.

So here at Weird Animal Question of the Week, we have to ask: What other “people skills” do crows and their cousins possess?

Corvids—crows, ravens, rooks, and their