Why do some tinamous pretend to be dead?

Some tinamous may feign death as a defensive strategy to escape predation. This behavior is a form of tonic immobility, an unlearned and reflexive state characterized by extreme motor inhibition that can make an animal appear lifeless.12

For ground-dwelling birds like tinamous, which are highly adapted for walking and running rather than sustained flight, this response serves as a last-resort defense. When a predator is present, the bird's sudden motionlessness may distract the predator or cause it to lose interest, thereby providing the tinamou with an opportunity to escape. While tinamous are best able to avoid notice by standing motionless or slipping away into cover, they may crouch or feign death when these other methods are insufficient.12