What is a behavioral adaptation of a baby bird in nest?

Dangerous for the bird. The parents will usually recognize the bird as a stranger and remove it. They may also detect your scent and reject the chick for that reason. Call animal control in your area (may be the police or sheriffs) and ask them if they know the number of the local organization that volunteers for bird rescue. Your veternarian will have this information also. Call them and they'll tell you exactly what to do.