Proper Diet is Critical

Mammals get calcium from their mothers milk during critical development, when they are weaned they continue to get calcium that builds and strengthens their bones.  Birds are not Mammals, and don't get any value from milk and it typically causes diarrhea, and thus dehydration that will lead to death.  The proper diet for raptors is absolutely critical for proper development, life, and flight.  Even three days with an improper diet can doom a birds life, and prevent them from ever flying.  We have seen the effects of well-meaning people feeding raptors peanut butter, milk and bread, chicken liver (very common, but devastating as it has no calcium) hot dogs, hamburger, fruit, seeds and all sorts of things.

Mississippi Kite with five fractures from improper diet.

It is against Federal law for a person to keep a raptor, or any other wild bird, other than a starling, pigeon or English sparrow. If you find a Raptor, do not keep it, even for a few days, as you may cause irreparable harm with an improper diet.  Keeping a bird in an improper enclosure can also lead to feather damage, which will prevent flight.  Turn the bird over to a Federally permitted rehabber as soon as possible,  and you may well save the bird's life.  Keeping it, no matter how well intended, may cause it's death.