With accent marks:
Видна́ пти́ца по полёту.
A bird is visible by its flight.
You can say anything about yourself, but only your actions will show your true value. A person is judged not by his words, but by his deeds.
The closest English equivalent is "A bird may be known by its song".
Other Russian proverbs
Appetite comes with eating.
Be patient, Cossack - you will become an ataman!
The best is the enemy of the good.
You are greeted by your clothes but bid farewell by your mind.
Live for a century, learn for a century, but die being a fool anyway.
A titmouse in hands is better than a crane in the sky.
The quieter you go, the further you'll get.
You see your friends in the times of trouble.