When determining if a raptor is ready for free flight, an important indicator is its response to the lure at the full length of the creance. If a bird comes to the lure instantly when it is at the creance's length, it demonstrates that the raptor is well-trained, understands the concept of returning to the lure, and is likely to perform reliably once it is free-flying. This readiness signifies that the raptor has formed a strong association between the lure and the reward of food, ensuring that it is likely to return to the falconer in the field.
While consistent good flying on a long creance is a good sign of a bird's overall flight capability, it does not directly confirm the bird's ability to return on command when it is free. Vocalization in response to the falconer may indicate a bond, but it does not ensure that the bird will come back when called in open flight. Showing reluctance to return when called could indicate training issues or a lack of motivation, which are not desirable traits for free flight. Thus, the best measure of a bird's readiness for free flight is its prompt response to the lure when at the creance's full length.