Why did thousands of dead birds fall from the sky?

My brother works in an R&D center, he is a scientist who studies the influence of various types of waves on living organisms. Well he and his colleagues believe that the birds could have died as a result of such influence. Allegedly waves of some frequencies could have coincided with the birds’ heart rhythm thus causing the resonance effect which led to the heart rupture because no heart can survive such an extreme overburden. He says that American military are known to be main users of the waves in such frequencies. And taking into account that in all places where the death of birds was registered Americans are either going to deploy their Missile Defense and therefore are conducting some equipment tests, or the MD is already deployed, or there’re some other American military facilities nearby, then it’s highly probable that they’re the main culprit of the terrible things. Imho you may expect such **** from them... The bad thing is that they keep on getting away with all such dirty tricks... Basically a thorough investigation should be conducted here and all the guilty persons severely punished so as to prevent such things in the future. Just fancy that next time the waves coincide with the human heart rhythm and not the birds but people will be falling dead!