Glad you all enjoyed the post and I will try to post more hunts as they happen!
There are a lot of different ways to raise birds for falconry and lots of different species you can use. It is very normal to release birds that were originally taken out of the wild as "passage" (first year- on their first "passage') birds. Those birds have left the nest and been on their own for a couple to a few months (like my red-tail). When you trap them and train them, they already know how to hunt and honestly, you mostly become their hunting dog (flushing game for them) and of course caretaker if they get sick, etc. A baby bird taken out of the wild ("eyass") is going to rely on you for a lot more- carefully building its confidence with hunting and taking larger and harder game as it gets older. Many of these birds taken as babies stay with their falconer for life. Captive bred birds are also often available and stay with the falconer for life usually.
In terms of the fledglings being larger- they often have longer tails (training wheels!) making them look larger than the adults. When a raptor comes out of the nest (almost all species, except some owls which will leave the nest before full grown) it is as big as it is ever going to be (in terms of size, not weight). They may still be growing in some feathers but their *bodies* are done growing. They may have some baby fat (if they had good parents!) giving them some weight over the adults but it also would not be uncommon for young raptors to be about the same weight as their parents when leaving the nest depending on how well their parents were feeding them. It is not a hard and fast rule that the young will be heavier than their parents but it certainly can happen if the babies are well fed. That being said, many young raptors are underweight quickly if they cannot figure out how to hunt quickly on their own. As someone said above, most raptors die in their first year- up to 80-90%. Pretty amazing to think that adult raptors you see or even young ones that have made it to winter have had to kill something every single day or almost every single day to survive. While it's true raptors can go some days without eating they still have very fast metabolisms and quickly go downhill once they hit a low weight. They are amazing critters!
