According to researcher Kaeli Swift of the University of Washington's Avian Conservation Laboratory, crows hold "funerals." When they see a corpse of their own kind they gather together and squawk loudly. To determine what they may be doing, Swift displayed a taxidermied dead crow to other crows. On some days though, she wore a creepy mask and wig. After multiple experiments with and without her disguise or the dead bird, the crows appeared to remember "the experience with the mask and dead crow and now connected the area with danger." From Deep Look:
And here's what Swift said makes that really interesting: These new mobs (she encountered even weeks later) contained crows that had never seen the masked Swift with the dead crow. But they still learned to avoid the masked figure.
Learning directly from each other, rather than through individual experience, is called social learning.
"By participating in these funerals, crows can get information about new dangers without taking the risk," Swift said.