Mass Death of Birds and Fish: Is There a Cover Up?

Puzzled by the mass deaths of birds and fish in Alabama? It’s also happening elsewhere, across the Eastern and Southern U.S. and around the world — Gizmodo has a handy map of all the U.S. events.
The Activist Post offers some theories. Before you read them, however, bear in mind what Yahoo News has to say about the subject:

“… [M]ass die-offs happen all the time and usually are unrelated … Federal records show they happen on average every other day somewhere in North America. Usually, we don’t notice them and don’t try to link them to each other …

And there have been much larger die-offs than the 3,000 blackbirds in Arkansas. Twice in the summer of 1996, more than 100,000 ducks died of botulism in Canada.”

Here are the theories listed by the Activist Post:

Mainstream Explanations: These have included lightning, hail, mid-air collision, power lines, and New Year fireworks for the birds, and a disease for the fish. But this seems like a heck of a coincidence, and where are the roasted birds from a lightning strike?
Meteor showers: During this period of intense seasonal meteor shower, some people reported hearing sonic booms in the area that might have been an indication of a local shock wave.
New Madrid Fault Line: Could it be related to the recent earthquake activity along a fault line that runs along the mid-eastern section of the U.S.? Could it have dispersed pollutants into the water and atmosphere?
Government testing: Only certain species have been affected, but within the entire region. And some reports have indicated that the organs of the birds were liquefied — could this implicate species-specific bio-weapons?
GMOs: There are other die-offs are happening across other species, such as bees and bats. Some think they could be poisoned by genetically modified plants.
Geoengineering: Could spraying in the area have caused this?
HAARP: Both birds and fish navigate in highly coordinated ways. Could the HAARP array off in Alaska have short-circuited their navigation systems? Or is it the result of electromagnetic pollution for other human devices?
Scalar Weapons: Some wonder if the cause is directed energy beam weapons deployed via satellite.
Project Blue Beam: Another theory is a sound generator weapon.
Geomagnetic and other Earth changes: The magnetic pole is moving. Add to this a dwindling magnetosphere and falling oxygen levels, plus an increase in sun activity and magnetic storms.

Update: A Wisconsin lab has apparently determined that the birds, at least, died of blunt force trauma.