In late May, wildlife managers in the District of Columbia, Maryland, Virginia, West Virginia, and other states began receiving reports of sick and dying birds. Several passerine bird species have been affected. No human health or domestic animal (pets, livestock, and poultry) issues have been documented. As of mid-August, reports have decreased in many jurisdictions and the Maryland Department of Natural Resources is lifting its previous recommendation to cease feeding birds.
The natural resource management agencies in the affected states and the District of Columbia, along with the National Park Service, continue to work with diagnostic laboratories to investigate the cause(s) of this event. Those laboratories include the USGS National Wildlife Health Center, the University of Georgia Southeastern Cooperative Wildlife Disease Study, the University of Pennsylvania Wildlife Futures Program, the Indiana Animal Disease Diagnostic Laboratory, and multiple state laboratories.
While no definitive cause(s) of illness or death has been determined, the following pathogens have not been detected, based on results received to date: Salmonella and Chlamydia (bacterial pathogens); avian influenza virus, West Nile virus and other flaviviruses, Newcastle disease virus and other paramyxoviruses, herpesviruses and poxviruses; and Trichomonas parasites. Transmission electron microscopy, metagenomics work, and additional diagnostic tests are ongoing.
Residents who choose to resume feeding birds and providing water in birdbaths should remain vigilant and consider the following standard guidelines:
- Clean feeders and bird baths with soap and water at least once a week, then disinfect with a 10% bleach solution to prevent potential infectious disease spread between birds and other wildlife. After cleaning, rinse well with water and allow to air-dry. When handling bird feeders and baths be sure to wear disposable gloves and wash your hands when finished.
- When feeding birds follow expert recommendations such as those listed in the Audubon International Guide to Bird Feeding.
- Avoid handling birds unless necessary. Dispose of dead birds in a plastic bag, seal, and discard with household trash, or alternatively, bury them deeper than 3 feet to prevent disease transmission to other animals. If handling is necessary, wear disposable gloves or use plastic bags on your hands to avoid contact with carcasses.
- Keep pets away from sick or dead wildlife.
- Report sick or dying birds to the Maryland DNR / USDA Wildlife Services Call Center at 1-877-463-6497 (410-349-8130 for out-of-state phone numbers). Licensed wildlife rehabilitators can be found on the DNR website.
Maryland DNR greatly appreciates the assistance of the public and wildlife rehabilitation facilities during this outbreak. Wildlife disease investigations take time and can be inherently challenging. Additional information and guidance will be shared as more results are confirmed.