What is the primary distinctive feature of a haggard bird?

A haggard bird is defined as an adult wild raptor that has been captured after having reached full maturity in the wild. This distinction is important in falconry because it indicates that the bird has completed its development and is capable of independent survival in its natural habitat before being trained by a falconer. This status as a fully matured wild bird contributes to its physical and behavioral attributes, making it suitable for falconry purposes.

Other features of a haggard bird, such as being wild and trained under the conditions present in their natural environment, also differentiate it from immature birds or domesticated species. The term signifies the wild status of the bird, which influences its training and handling compared to birds that are bred in captivity or still in their juvenile stages.