Quote Originally Posted by Tom Smith View Post
That is very much what happens when one takes a passage bird. The passage bird is an imprint on it's parents as all birds are. We can assume the passage bird was for a time a screamer and when it is taken by a falconer it quits screaming with the change of parent and address. You have probably seen a passage bird that it will scream at a passing adult of it's species and may even mantle and flutter it's wings a little, in an attempt to return to it's roots.
Then one other complexity in the mix: When a passage bird is held by a falconer for years the passage bird begins to look on the falconer now as its new provider and seems to switch from imprinted to its parents to imprinting to the falconer.

And another: Although we know that getting a bird hunting hard greatly reduces screaming. It doesn't however totally / completely stop it. I suspect that even the bird that now hunts for it's own meal realizes that it's the falconer still that suddenly appears and transports it to the field where it can hunt and kill. So even a well made hunting bird is still somewhat dependent upon the falconer - something that doesn't occur in the wild, where the cut with the parents is permanent and complete.

And yet another observation is that during the molt, that bird that has developed into a "independent" hunter, is once again provided with handouts from the falconer. Once again, the ties are never really as broken as they are in the wild.