pulse this

Mystery solved then?

http://abcnews.go.com/Health/radar-images-show-startled-birds-taking-flight-arkansas/story?id=12781951

A bird scientist has isolated weather radar images that he says show exactly what killed the 5,000-or-so birds that fell dead from the sky over Beebe, Ark., on New Year's Eve.

Sidney Gauthreaux, a biological sciences professor at a Clemson University lab that studies radar images of birds, said a cloud burst on weather radar animation captures a series of pulses of startled birds taking flight in the Little Rock suburb.

That's right. Those pulses are the startled birds taking flight.

"There is no question that the exodus of birds from the roost is visible in the radar display images," Gauthreaux said in a statement released by the Arkansas Game and Fish Commission. "The first exodus occurred about 10:20 [p.m.] and contained approximately 6,000-7,000 birds per cubic kilometer. ... At 11:21 p.m., another pulse of birds with a slightly smaller density left the roost."

The commission declared this week that three labs now confirm the bird deaths, which spooked Beebe residents and piqued the interest of conspiracy theorists, were caused by blunt force trauma.

Wow pretty late fireworks they have down there.

The pulses are the startled birds taking flight. The birds died by blunt force trauma.

How do the radar images "show exactly what killed the 5000-or-so birds"?

The labs found loud noises, probably fireworks, sent the birds soaring into the air and into trees, houses, windows and other stationary objects.

Aha, so the loud noises, PROBABLY FIREWORKS, startled the birds and made them crash into stationary objects.

Right.

The pulses on the radar were the birds.