I feel that way about horses in movies—I look at them and think, “They don’t know they’re in a movie.” But birds’ mates do know what they look like. Otherwise they wouldn’t look like that.

I once fell asleep under a tree & when I woke up there were maybe 6-8 Stellar’s Jays peering down at me. At first I thought they might have a nest but they weren’t scolding me. Later realized the neck pillow I was wearing was the very shade of blue of the Jays.😉

on the other hand if they do they might get territorial and attack it like a cat.

the cardinals constantly at war with the side mirrors on my car may beg to differ... 😆

How about seeing their reflections in the water?

The Jays, more than their other fellow feather friends, r notorious 4 attaching those that threaten their nests. I'll have 2 ask my sister if she remembers walking under a spruce when she was 8, clueless that they were nesting. It flew down & took a couple of pecks from her head.

Alex the African grey parrot: Looking at a mirror, he said "what color", and learned "grey" after being told "grey" six times.[16] This made him the first and only non-human animal to have ever asked a question—and an existential question at that.

For some birds, perhaps it's best.

Wonder what this one sees

That’s a very good thought, Marianne