This is cool, but isn't that surprising, if you think about the behaviours of other species, and that corvids as a whole are highly intelligent and use tools in a fashion akin to primates.
I mean, primates give gifts to each other and humans, and my cat loves nothing more than to leave the most succulent bits of viscera of whatever her prey was for me on Persian rugs, for me to enjoy, by which I mean tread on while heading to the shower in the morning.
I mean, primates give gifts to each other and humans, and my cat loves nothing more than to leave the most succulent bits of viscera of whatever her prey was for me on Persian rugs, for me to enjoy, by which I mean tread on while heading to the shower in the morning.