Each night this week, an artificial fog will roll through the Village at Shirlington.

Its purpose is to get a murder of crows, which once again wintered in Arlington — doing their business near the Shirlington businesses — to leave and not return when roosting begins again in October.

The descent of crows on Shirlington for the winter is an annual occurrence going back to at least 2017 and leading to a bombardment of droppings on cars, mailboxes, trash cans, sidewalks, patios and tables.

This year, Federal Realty Investment Trust, which owns the retail center at 2700 S. Quincy Street, is trying a new way to deter the persistent perchers and their prolific pooping.

“Federal Realty has partnered with a wildlife management company to implement a Passive Deterrent System to mitigate the nuisance issues and community property damage caused by large flocks of roosting crows,” a spokeswoman for FRIT said. “This system deploys a fog to targeted areas within the tree canopy. This is a humane and non-lethal means to relocate these specific large flocks of crows.”

The fog was first released this past Monday and will be emitted every evening from 7:30-9:30 p.m. until this coming Monday.

More information from FRIT was distributed to residents of a nearby apartment complex and obtained by ARLnow.

The fog “has been a successful approach for several communities, companies and agencies, including the FBI Headquarters, Miami International Airport and the Smithsonian,” FRIT told local residents. “We feel very confident that this process will be an effective strategy to relocate the roosting birds on [the] property and discourage them from returning to roost in the future.”

The fogging has raised concerns for Diva Crows, an organization in Northern Virginia that cares for injured crows and ravens. The Animal Welfare League of Arlington, which handles animal control for the county, meanwhile, is keeping tabs on the situation to see if the fog causes an increase in injured or dead crows.

Sam Sparks, who works for Diva Crows, says this fog is made of a vaporized chemical called methyl anthranilate.

The chemical — which produces a grape odor — irritates the pain receptors associated with birds’ senses of taste and smell, according to one bird repellent company.

“There are two separate concerns,” Sparks says. “One is human exposure to the pesticide, for which there are limited studies on the toxicity to mammals. People have the right to know that they will be exposed to this for the next seven consecutive days that the fog will be deployed.”

Sparks added that this is “baby season” for wild birds, and the deterrent could lead parents to abandon their fledgling offspring, leading to dead baby crows littering Shirlington sidewalks.

It may also not drive them away for good, as crows are adaptable and have to be outsmarted through variable and unpredictable deterrence strategies.

AWLA spokeswoman Chelsea Jones said the animal control agency became aware of the deterrent efforts after receiving several complaints from citizens and business owners about the volume of bird poop.

“We have spoken with the property managers to offer other humane deterrent methods, and have also been in contact with local and state agencies,” Jones said. “This is a legal deterrent method and we have been assured that there is no risk to human or wildlife health.”

Around this time, crows are set to begin their migration, so residents should see a natural, temporary decrease in the local crow population “very soon,” Jones said.

“We have not found any deceased or injured crows thus far, but our Animal Control team continues to monitor the situation,” she said.