An adult songbird that can't fly has a problem. The problem might be an injury, such as hitting a window, being attacked by a predator, or being hit by a car. It might also be an illness that has weakened the bird to the extent that it cannot sustain flight. Diagnosing the cause of the flight problem requires either a wildlife rehabilitator or a veterinarian experienced with birds. Contact a wildlife rehabilitator for advice and refer to the Emergency Care section for this website.