Why do tinamous wait until danger is very close before taking flight?

Tinamous are highly adapted for ground dwelling and rely on their concealing plumage to avoid detection. Because they are better suited for walking or running than for sustained flight, they prioritize remaining unnoticed by standing motionless or quietly slipping away into cover.

They only take flight when they are almost stepped upon because their flight is clumsy and they tire very quickly due to a limited circulatory capacity. Consequently, they reserve flight as a last-resort escape mechanism when their primary defense—blending into their surroundings—is no longer effective.1