(WFXR) — The Virginia Department of Wildlife Resources (DWR) is continuing to work with various wildlife health labs to determine the cause of birds dying across the Commonwealth. Investigators and experts are looking at all avenues for the cause of illness or death, such as toxicology (herbicides and pesticides), viral, bacterial, and parasitology.

The DWR started seeing reports of sick and dying birds with eye issues and neurological symptoms in late May. These symptoms were seen in young common grackles, blue jays, European starlings, and American robins. Songbirds also showed signs of avian sickness but the numbers reported were low.

In early June, the department was able to pinpoint the areas that would be most likely affected by this mortality event throughout Virginia. That included Alexandria, Arlington, Clarke, Fairfax, Falls Church, Fauquier, Frederick, Loudoun, Manassas, Prince William, Shenandoah, Warren, and Winchester counties.

The DWR says that those affected areas saw a decrease of 50 percent of reports of dead or sick birds. The Animal League of Arlington (ARLA) also reported a drop of an average of 17 reports per day during early June to 1.5 reports per day in July.

Virginia wildlife officials recommend that people continue to not use bird feeders in the affected areas until further notice. To prevent the possible spread of the mortality event, they advise the rest of the Commonwealth to remove bird feeders if there are reports of multiple dead birds observed on a property over a short period of time.

Feeders and birdbaths should also be cleaned and disinfected. The DWR recommends a 10 percent bleach solution (one-part bleach mixed with nine-parts water), then rinse with water and leave it to air dry. To keep wild birds healthy, it is best to clean bird feeders and baths at least every two weeks.

However, if you encounter a sick or dead bird, you are asked to report it to the DWR by clicking here.

The department also states that to dispose of the dead bird properly, place it in a plastic bag, seal it, and discard it with the trash. On the other hand, you can bury the bird three feet in the ground.

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