Does any one know what that Blue Bar underneath the Hit Bar is?

Does it indicate something, or is it nothing?

The blue bar means that if you miss shooting a duck for a certain number of rounds, you get a game-over.

The blue bar indicates how many ducks you need to shoot in that round. When the round is over the duck icons at the bottom move to the left and if the hit ducks are equal or higher than the bar you pass the round

Ah, makes sense