Pity the poor blackbirds, cowbirds, crows, grackles and magpies.
Some of their species are singled out from all the other migratory birds for special treatment under federal law.
They can be poisoned by farmers or other landowners if they damage crops or livestock feed, cause a health hazard or structural damage, or to protect an endangered or threatened species.
And nobody needs a federal permit to do it.
Other migratory birds — even the Canada geese that rip up grasses and other plants and leave bucketloads of feces behind — can only be killed if farmers or others having problems with them get a federal permit. And they can’t be poisoned, just shot or trapped, said Kim Clapper of the U.S. Department of Agriculture’s Wildlife Services Program in New Jersey.
So when about 200 red-winged blackbirds died in rural Stow Creek Township on Nov. 22, many people assumed it must be a bird kill caused by a farmer’s use of a toxicant — a chemical also called an avicide that can be embedded in seed.
The Cumberland County Health Department and the New Jersey Department of Environmental Protection responded, and the DEP took samples of dead birds, but the cause of death isn’t known.
“Our pathologist is reviewing the necropsy and so far hasn’t been able to find a cause,” said spokesman Larry Hajna, adding initial toxicology reports came back negative. “The necropsy reported hemorrhaging and internal bleeding, likely related to the trauma of falling from the sky.”
A smaller die-off of birds was reported Nov. 3, said Cumberland County Health Officer Megan Sheppard.
Hajna said the smaller die-off included red-winged black birds, starlings and other species, while the larger one Nov. 22 was almost exclusively red-winged blackbirds.
On Friday, Hajna said it is looking like the cause was not poisoning, but he said he could not elaborate further until getting more test results.
Mass bird die-offs happen fairly often, experts say, and some have been proved to be caused by blunt-force trauma without any underlying toxin or disease.
Researchers showed up to 5,000 red-winged blackbirds that fell from the sky Dec. 31, 2010, in Beebe, Arkansas, had no disease or toxins in their systems.
Instead, they had likely been frightened by New Year’s Eve fireworks into flying at night, and being poor flyers in the dark they flew into homes, cars and power lines, according to a Jan. 6, 2011, report in the Wisconsin News.
New Jersey Audubon’s Vice President for Stewardship John Cecil said he has not heard of large-scale die-offs of blackbirds from disease in New Jersey. Toxicants are generally the more likely cause of large numbers of bird deaths, he said.
But he said his organization, which works to protect birds in the state, doesn’t see farmers’ use of avicides as a big issue threatening birds.
“The major issues affecting bird species in New Jersey … (are) habitat loss, crashes into windows or wind turbines,” said Cecil. “We have concern about pesticides in some instances, we are looking at the impact of neonicotinoids (a class of insecticides related to nicotine) on pollinators and the cascading effect that may have on bird populations.”
He said he understands why farmers need to protect their crops from huge flocks of birds like blackbirds and non-native birds like starlings (also not protected under federal law).
“In some instances they may be competing with native species like bluebirds, which are historically declining. There are instances in which we might want to see some control,” Cecil said.
Liz Thompson, a research associate with the New Jersey Farm Bureau, said huge flocks of blackbirds can not only damage crops, their droppings can contaminate livestock feed and cause disease.
She said farmers work with USDA’s Animal and Plant Health Inspection Service to develop a plan for handling destructive birds. Those plans usually involve harassing birds to get them to leave before turning to a lethal method.
In 2012, a die-off of 200 to 300 blackbirds in Millville was traced back to a farmer’s legal use of an avicide. In that case, dead birds fell into a suburban neighborhood, causing widespread alarm.
That case caused a great deal of concern for Jane Morton Galetto of Citizens United to Protect the Maurice River and Its Tributaries.
“Our biggest concern whenever we see large bird kills (from avicides) is, are nontarget species being killed, and does the poison persist in the environment?” Galetto said.
She would like to see farmers warn the community when they put out avicide so residents will understand why they are seeing large numbers of dead birds and the Health Department and DEP won’t have to spend time and resources determining the cause of death, she said.