The thought came to Sindbad that he could use the birds to escape from the valley. He gathered some of the biggest precious stones he could find, which he put in his wallet and attached to his waist. Then,  he attached one of the huge bits of meat to his back with his turban. Roc was a huge bird. The size of the bird could have frightened him in any case however, at that point, he kept calm, and without panicking and without hurting any of the birds, he left the place. If he doesn't harm birds, they help him to escape.