I’m going to put this one on the list. Bird intelligence is fascinating and among crows, jays, and magpies (corvids) really impressive. Crows and jays don’t just learn to recognize human faces to identify threatening people, but teach their young about them, and engage in funeral-like rituals when a known member of the species dies.
The New Caledonian crow isn’t just really intelligent in terms of tool use, they understand things like water displacement (and will use pebbles to manipulate water levels), but also will cooperate with each other to share tools to solve problems:
They’re absolutely amazing. The Hawaiian crow has similar tool using and cognitive abilities, though alas, they’re extinct in the wild:
Many passerine birds are able to engage in inter-species vocal communication. Chickadees share warnings about threats (with different warning calls for different types of threats) and send calls to mob predators which are understood by kinglets, warblers, titmice, and other passerines that join in. Even squirrels and rodents will learn to understand Chickadee’s calls to identify threats.
