If the tendons in a bird's wing are torn, the bird will not be able to fly because the muscles will no longer be able to exert force on the bones to generate lift. Essentially, the bird's ability to flap its wings and generate enough lift for flight is compromised. Without functional tendons, the wings cannot move properly, and the bird loses its flight capability.
Moreover, torn tendons can cause significant pain, swelling, and inflammation in the wing, further hindering the bird's ability to fly. In some cases, the damage to the tendons may be so severe that surgical intervention or rehabilitation is necessary for the bird to regain flight ability.