STOW CREEK TWP. -- Authorities are still investigating what killed an estimated 200 to 300 red-winged blackbirds in this rural township.
The dead birds were found near Frank Davis Road on Nov. 22, according to Cumberland County Department of Health Director Megan Sheppard.
The were found on the road, in farm fields and in wooded areas. Some of the dead birds were also found on some nearby roadways.
There has been no cause yet determined as to what killed them.
As for humans, Sheppard says there appears to be no threat.
"Not at this time, we don't have any concerns," she said Wednesday, noting no unusual illness has been reported in humans or pets in the area.
The area where the dead birds were found is an agricultural area not far south of the Stow Creek's border with Salem County.
The dead birds have been cleaned up, Sheppard noted.
She said that in the same area about a half a dozen blackbirds were found dead at the beginning of November, too, but nothing on the scale of what was discovered last week.
New Jersey Department of Environmental Protection Spokesman Larry Hajna confirmed Wednesday his agency has become involved in helping to determine what killed the birds in this latest incident. He noted the state Department of Agriculture is playing a role in the probe, too.
"Necropsy results have been inconclusive,"Hajna said. "No pesticides or toxins were detected in the first round of testing."
Sheppard suggested that a final answer through toxicology tests "could take weeks."
Officials said the unidentified farmer around the land where the birds were found has been cooperating with the investigation.
There was a similar bird kill in the Millville area in the summer of 2012.
It was later determined that the kill was caused by a farmer's proper use of pesticides to get rid of the birds, which destroy crops.
Bill Gallo Jr. may be reached at bgallo@njadvancemedia.com. Follow Bill Gallo Jr. on Twitter @bgallojr. Find NJ.com on Facebook.