Devil’s Advocate here: reflections are mostly seen in standing water in nature. Water is needed by all living organisms, so visually detecting water in your environment confers a distinct survival advantage. This may be more about staying alive than high level thought processes.
Animal behavior
Well hello, handsome!
Yeeeah, but sometimes they see it and just get pissed off.
I'm not even joking. Our rooster catches his reflection sometimes and goes batshit trying to fuck it up.
Then again, he tries to fuck up anything, most days. Ornery bugger, he is. He's got one of those hanging thingies with bells and beak grinding materials. Fucker will stomp circles around it any time the wind moves it. Spike some lettuce and hang it? Fucker attacks it for a minute until he realizes it's lettuce and not a green invader.
Squirrels, most birds, sticks? That's the enemy, and they must be chased or destroyed.
He does, however, allow cats and rabbits. He has also learned not to fuck with blue jays or catbirds. Crows, he was never dumb enough to threaten.