The government released this picture today over all of the functioning news networks.

So what does this mean? Obviously birds still exist, but where? And where was this taken? They said the top scientists were trying to determine the cause of the bird-ocalypse but no conclusions had been reached.
My hypothesis? A chemical was released into the air causing the birds to drop. It had to spread quickly. It then mixed with the water molecules in the air forming chemical rain which fell into bodies of water, killing the fish. But who knows?