Found: Prince (?) flees after usurpation, joins rival army

Trying to find a book I read in middle school ('95-'00)

Below are some of the key elements, as far as I recall:

Written for youth / YA

Medieval "fantasy", but no magic, no elves, no overt fantasy elements that I recall, but not historical fiction either

Young male protagonist

Rightful heir / prince / noble

Usurpation or coup

Forced to flee

Lives under an assumed name

Some important bird association. Either the protagonist has a bird-related alias or nickname (hawk, falcon, raven, etc.), or the protagonist has a bird that is central to his character

Becomes part of or leads a resistance group or rival army

Female protagonist who remained with usurpers is shocked by the things the hears about the protagonist initially, not realizing his true identity

True identity revealed near the end

How vague is your memory/how confident are you?

Because there's a chance this is The Kestrel from the Westmark series by Lloyd Alexander.

Theo, a printer's assistant, is tricked into printing a revolution pamphlet by Count Bombas. He ends up on the run with Bombas and a beggar girl (Mickle). Ultimately, she is revealed as heir to the throne; and due to brutalities he witnesses during the war, he becomes a terrifying figure known as "The Kestrel." Angels tremble when a good man goes to war.

Holy smokes, BrainFireBob, I think that's it! My memory was very clouded, so good job making sense of a bunch of details that were not quite right. Thanks, I've been trying to figure this out for years!

>2 BrainFireBob: the touchstone links to a different Kestrel (interesting too!) but thanks to your description it works out anyway. here is the intended one just in case The Kestrel

Glad to help. I've benefitted from this board, so it's a pay it forward space for me.

Alexander's Westmark is an under-rated gem.