Stock Pile m&m's
The key lies in their candy coated shell. Whether by design or simply by coincidence, the shell of an m&m acts on ostriches like garlic does on a vampire. It has something to do with the chemical composition of m&m's which allow them to melt in your mouth and not in your hand.
When the time actually comes and the ostriches do invade, you can be ready by having a ready supply of m&m's. Don't worry about the m&m's going bad, they actually work better as they age. These guys are our dearest friends. If you see someone about to eat some m&m's, please stop them. They probably don't even know about the ostriches or the value of m&m's. Save the m&m's and by doing so you're saving yourself.
Apparently, some ostriches have infiltrated the U.S. government. In attempt to thwart our only means of defense, they made a deal with the owners of Mars Inc. and got them to stop productions of the Light Tan m&m's and replaced them with Blue. Light Tan m&m's were the best of the best, if we had them, the ostriches wouldn't stand a chance. Unfortunately, few still exist. Scientific tests prove that the Blue m&m's are far weaker than the other m&m's. A Blue m&m won't even phase an ostrich. If by some miracle, you happen to have any Light Tan m&m's from before the conspiracy, keep them safe. Guard them with your life. When the time finaly comes and the ostriches do attack, place a Light Tan m&m at every entrance to your home and the ostriches will not be able to pass.
Just remember
STOCK PILE M&M'S!!!