I'm fascinated by birds. It's not that I'm a lister, but I'm always aware of birds around me, from their vocalizations. The stereotype of "bird watchers" with their binoculars and scopes is misleading. Mostly you identify birds by sound.

Anyway, avian evolution has diverged enough from our line that birds are virtually aliens. Compared to other primates, and other smart mammals, I mean. Also rather alien are spiders, octopus, and colonial insects.