Concerned residents contacted authorities on Tuesday after the birds started dropping from the sky in the area of Peach Drive.
"First we saw one bird, it looked just hurt, and then we saw another one run into a house, then we get back on the street and they were just falling from the sky. Anywhere you walk, there's a dead bird," Millville resident Michelle Cavalier said.
The birds included red-winged blackbirds and a few a sparrows.
"They were flying like erratic, they crash into stuff, fall in the ground, they were screaming. They'd get up, try to fly, and every now and then you'd see them just quiver," resident Jim Sinclair said.
At first, not sure what was occurring, authorities issued a precautionary reverse 911 call to Peach Drive and nearby streets.
The message stated, "Please stay indoors during an investigation into an odor and the death of several birds."
It is estimated dozens of red-winged blackbirds died. But some including one young bird survived and small songbirds showed no ill effects.
At first, investigators looked into the possibility that a gas leak may have caused the birds to die.
However, authorities soon focused on a neighboring farm. The belief is that a farmer had recently used a pest control product to kill birds that were feeding on his crops.
"Some kind of pesticide they use that the birds ingest and, of course, it's effective in killing them, obviously, because we have a lot of dead birds," Cumberland County spokesman Troy Ferus said.
The county identified the pesticide as Avitrol, an acute oral toxicant which is sold as a chemical frightening agent that suppresses a bird's nervous system.
Some birds that feed on it and flail in such a way that, its maker claims, they will frighten the rest of the flock away from the crops.
Workers at the field had no comment referring Action News to a nearby retail stand, Ingraldi Farms, where workers said the owner had no comment.
One Peach Drive resident, irate over the bird kill, was wondering about the residual effect of toxics used in the field.
"What's the cost of having for three years of dumping these pesticides on the piles of corn, having it run into the groundwater, what's the effect of that going to be on the long term," resident Gregg Kears said.
Action News is told the farm stand owner, who is the farmer, did respond to county agents when they contacted him.
He did confirm to using Avitrol last night. He is licensed to use it.
The farmer said he put it down because so far this year he has had $15,000 in crop losses due to birds.