The only way for you to obtain the three star rating is to kill all the birds in one shot. You will try this a handful of times before the explosions land in the right places. Aim directly at the spears.
Power Activation Point
Right before you hit the spears, activate the dual jedi swords. You have to trigger the TNT bomb explosion with the shot.
First Shot Result
The flying bone pieces from the explosion set off all the floating platforms. The platforms move around and kill all the birds in the stage. You will then walk away as a three star master.