You as one of the captains of the army, it's an urgent message from headquarters, where it was said that due to the leakage of the virus in one of the secret laboratories outside the city, all the birds that were in the woods ill with an incurable disease, and became very wild and ferocious, and your task is to use your gun and shoot all the birds. Do not let your birds break through the roadblock, as if they fly on it can infect all the other birds, and then happen is the greatest disaster. Shoot accurately and do not let them fly.