Pause in-game. Then, select Options then Controls. Enable the Aiming Visor for easier aiming and the Inventory to keep track of your ammo.
X + A : Grabs an enemy and slam it\'s head
Y + A : Body slam
B + A : Charge
When the level begins, take a spear, skewer a dragonfly nearby and then throw it near where the birds/bats are. Run across and repeat the process with the other birds. This will save you more bullets for the later parts of the level.