Ahaha, totally random bump, but I just read this today...
Was doing a translation from Urkunden of a text from the Thutmoside period, and it talks about how Thutmosis III was a bik aA im.y ss=f, 'a great falcon in his nest'.
Lots of boring lexical and grammatical comments aside, this may mean one (or more) of the following:
1. That he was a young pharaoh, in fact too young to rule properly,
2. simply that he was successor, and being prepped to be king,
3. that he was brave in battle and would defend himself and his men in battle like a falcon would protect its young. Or something along those lines.
I think 2 is unlikely because successors were very rarely named in this period (lots of reasons why, can outline them if you'd like). I think 1 is unlikely because you are either a falcon (king) or you're not; you're never a young falcon. If you're a falcon, you're a young adult male, capable of leading the men into battle. It also seems strange to me that he is described as a great falcon, if he were indeed young; aA denotes size, age, maturity, strength, etc, as well as general greatness.
I think 3, or a variant of it is more likely. The term for falcon is frequently used in metaphors (as above) or in similes (eg mi bik iyi.t, like a falcon going), and I think it's probably emphasising the farocity of a falcon defending its nest. There is a frequent epithet of Sekhmet which involves her as a lioness defending her children, and I wouldn't be surprised if it's the same thing.
Anyone who's been dive-bombed near Australian magpies' nests will know what I'm talking about. To see a falcon defend its nest must be quite amazing.
Anyway, I think what you've read is an interpretation based on either 1 or 2.
