Imprinted Vs. Non-Imprinted Captive Bred BirdsEdit
Birds taken from the nest as a downy bird still unable to fly (fledgling) are called 'eyas', or the plural, 'eyasses'. In addition to wild-taken eyas hawks, all captive bred hawks taken at this same stage are properly referred to as 'captive-bred eyas' hawks. Eyas hawks can be the best or the worst of the hawks - they will never learn to fear man as the passage or the haggard bird has and are therefore difficult to lose; but likewise from this very lack of fear they may never learn 'respect' for the falconer. This results in eyas hawks sometimes becoming 'food-aggressive', constantly screaming for food or attention or being unnecessarily 'footy' (to grab aggressively at the falconer). Vigilant care regimes must be followed to prevent these bad behaviours in the eyas hawk.
Today experienced falconers know how to rear an imprint so that it has few or none of these undesirable behaviors, but it is time-consuming and requires unswerving dedication for a period of about three months. During that time, the eyass is not allowed to ever become truly hungry, and in nearly constant company and visual range of human beings, so that the arrival of food is not specifically associated with the arrival of humans. This bird is still very much imprinted on humans, but not Food-imprinted, so the human is not considered something to be screamed at or attacked when hungry. In order to further assure that such correlations are not made, when it becomes ambulatory, some will take the bird to a separate room/area and allow it to "find" a plate of food, rather than having that food delivered to its face for it, as a parent bird would do. Finally, the young eyass is allowed to wander about at Tame Hack and enjoy more autonomy than would be possible with a chamber or parent-reared bird (owing to that the bird's affinity towards humans will keep it relatively close by, an affinity lacking in the chamber/parent reared eyass.) This provides the imprint eyass with an opportunity to learn to use its wings and develop musculature as well as the ability to fly in adverse conditions -- advantages that the chamber-raised bird does not have.
In the United States, the law requires that all hybrid raptors must be either imprinted or sterilized before they can be free-flown.