Birdbrain is a flying enemy that begins appearing from Stage 4 and onwards. It is an enemy with fast projectiles, high health, and a decent attack power. They are still significantly less dangerous than other enemies, and can be easily detected by their loud projectiles
Birdbrain begins appearing first on Stage 4, forcing Kurt to be careful in large rooms. They also appear in the following stage and respawn infinitely until Max leaves the incubation room.
Some giant Birdbrains appear in Stage 10 when the doctor scales the ramparts, but, besides their increased size, do the same damage and have the same health as the smaller ones.
Birdbrains have a loud engine noise that is detectable when close, but their projectiles are the most likely way to notice their presence. They emit an incredibly loud screeching noise as they fly through the air.