When birds run into windows killing themselves, is that an expression of reflex or cognitive bias? Are birds capable of the rational thought to avoid running in

When birds run into windows killing themselves, is that an expression of reflex or cognitive bias? Are birds capable of the rational thought to avoid running into windows or is their brain only wired for impulse? Clearly birds are smart enough (at least some species) to be able to mimic human voices and perform complex tasks (carrier pigeons). They learn where the food is and hang around boats or people (seagulls / pigeons). So maybe this is not a solely-human characteristic?