For their study, Sarah Jelbert and her colleagues first trained three hooded crows—Glaz (15 years old), Rodya (4 years old), and Joe (3 years old)—to recognize pieces of paper of different sizes and colors. To do this, they exposed the birds to “template” pieces of paper in different colors and sizes for several minutes before removing them—and then rewarded the birds for dropping scraps that matched these templates into a small slit.

The crows were next given the opportunity to manufacture versions of these objects in exchange for a reward. The researchers found that all three crows manufactured objects that matched the original template object they had been rewarded for in both color and size—even though the treats in this second stage of the experiment were awarded at random. The researchers also observed that Glaz, the oldest of the three hooded crows, seemed to be the most proficient at making scraps that looked like the ones the bird was trained on. This finding suggested to them that mental templates may be linked to experience garnered with age.

Unlike humans, who regularly copy each other’s behavior [...] we don’t have much evidence that crows will watch each other and deliberately copy what another crow is doing, However, they will steal each other’s tools—in particular, juvenile crows often steal their parents’ tools when they are young. So it’s possible that young crows learn how to make different types of tools from experience stealing their parent’s tools, using them, remembering what these tools look like, and then trying to create something similar.

Crows and ravens [...] hold grudges against each other, do basic statistics, perform acrobatics, and even host funerals for deceased family members.