Because if she does like you she doesn't want you to be jealous or she doesn't want you to think she already has a boyfriend. But mostly she must be a bit shy!
There could be various reasons why she ducked her head. It's possible that she felt embarrassed or shy around you, especially if she likes you. She might have wanted to avoid making eye contact or drawing attention to herself. It's best to communicate with her directly to understand her actions better.
Waddling.
to waddle
Pray and duck
waddling
Walking on, swimming in water.
Waddle.
Waddle
If you think it's a duck when there is loads of ducks around, then it's a duck, and i don't see why you should be worried in the first place?
Alex Das
he likes you
guess he likes the breeze..
If you are asking how ducks walk, they waddle.