Hi CaraChick R-Jay,
Depends on what you mean by all grown up R-Jay. If you mean, when are they the same size as their parents, that would be about 35-40 days of age, but they can't fly yet. If grown up is when they can fly, that's between 40-55 days. But they won't be good at hunting for their own food until they are 80-100 days old or even longer sometimes. They will migrate by themselves or maybe with their brothers and sisters when they are 4 or 5 months old - that's kind of grown-up too. Or maybe they are grownup when they are 1 year old and they don't look like baby peregrines anymore, rather they look just like their parents.
So you can see, it depends on what you think is grown-up for a peregrine R-Jay!
The Peregrine Chick
