The loud booms heard in Grand Island Tuesday night and this morning are believed to be starling control measures or the acts of curious youth. Milt Moravek, program manager of the Central Platte Natural Resources District, said the NRD began shooting off propane cannons last Friday night for starling control.

"It just scares them away from our area," Moravek said.

The NRD has used the sound abatement method in the past to prevent the flock from roosting at the NRD headquarters office at 215 Kaufman Ave. It informed the city last week that the cannons would be shot off around dusk for about seven to 14 days.

But Grand Island/Hall County Emergency Management Director Jon Rosenlund said the 911 center received calls about loud booms from "one end of town to the other," and the calls came after dusk.

They were reported between 9:30 and 10 p.m. Tuesday and again around 7 a.m. today.

Rosenlund said reports were especially prevalent "up and down Stolley Park Road."

"There were no reports of fire, no reports of damage, no reports of power outages or any infrastructure damage," Rosenlund said.

Grand Island Utilities Director Gary Mader said he heard the boom Tuesday night and called in to the city's power control center.

"It's not us," Mader said. "It didn't seem to be affecting the electric system."

He said the boom almost sounded like a "sonic boom" that is sometimes heard from traveling aircraft.

Calls to the Central Nebraska Regional Airport this morning were not immediately returned.

Other infrastructure also appeared unaffected.

"It's not us," said Claudia Rapkoch, spokeswoman for natural gas provider NorthWestern Energy.

Rosenlund said his supposition is that people are hearing the NRD starling control, that local residents are implementing their own starling control measures or that area youth may be experimenting with something like a "dry ice bomb."

Rosenlund, who didn't advocate this being done, said that, when dry ice is dropped into a 2-liter bottle of water, a loud explosion can be the result. The technique has been featured on the cable television show "Mythbusters."

The city of Grand Island has contracted with the U.S. Department of Agriculture for starling control in the past, but no such work is currently under way.

"The city has not received any calls from citizens regarding problems with starlings," said Paul Briseno, assistant to the city administrator.

USDA officials have been tracking the birds, Briseno said. They believe the birds are moving to the area later in the season this year, and for the most part, the flock that is here stays in Grand Island the majority of the year.

"If we start to see an increase in the number of birds and complaints, we will once again initiate the same program as we have in past years," Briseno said.