Take a look at what has been happening. It is not just the Arkansas birds, its other birds, other fish this is happening too. They are giving you explanations, but they seem like far fetched ones. Fireworks? Gasses? Testing? What? Below is an account of all the known issues (for me anyways). Here is the googlemap of all the locations. As always feel free to discuss below.
Maryland (Fish)
Louisiana (Birds)
Arkansas (Fish)
Kentucky (Birds)