Avian influenza (AI) is an influenza type A virus that occurs naturally in wild aquatic birds, including ducks, geese, and gulls. Mild forms of avian influenza (known as low pathogenic avian influenza, or LPAI) are routinely found in wild birds and don’t cause serious illness.
From time to time, a mild strain changes through mutation or mixing with other flu viruses into a more severe type of the virus (highly pathogenic avian influenza, or HPAI). HPAI historically has caused 75-100% mortality in poultry, like chickens and turkeys, as well as some wild birds.
Avian influenza is transmitted between individual birds by ingestion or inhalation and between farms by breaches in biosecurity practices. Infected birds shed avian influenza virus in their saliva, mucous, and feces.
Since late 2024, the highly pathogenic avian influenza virus H5N1 has been spreading rapidly through wild bird populations. Waterfowl and seabirds have been hit hard. Raptors and corvids are increasingly becoming victims—including Bald Eagles, Turkey Vultures, and American Crows.
Infections in waterfowl spread easier because they gather and forage in large flocks. Raptors can pick up the virus when they prey on infected birds. The current outbreak also has spread into dairy cattle, domestic cats, many species of wildlife and also a small number of people. Cases in songbirds are uncommon at this time.
Because cases in songbirds are uncommon, bird feeders are not a top concern at the moment, though experts emphasize that cleaning feeders regularly is crucial to prevent the spread of all kinds of avian disease. Every other week is a good starting point for cleaning seed and suet feeders. Hummingbird feeders need more maintenance because sugar solution is a petri dish for bacteria. Empty and clean every few days (or even more often when it’s warm out). Scrub most feeders with soap and water (for hummingbird feeders, you can skip the soap), followed by a 15-minute soak in a 50-50 vinegar-and-water solution (or 10% bleach solution) to sanitize. Remove any residue with a thorough water rinse. If your feeder is dishwasher-safe, let your appliance’s soap and hot water do the work. No matter how you clean, it is key to completely dry a feeder before refilling it with food. Leaving moisture inside is a sure way for fungus or bacteria to flourish.
It’s also worth weighing what kind of environment your feeders are in and their possible proximity to the species that are most impacted by avian flu—like poultry if you live near a farm, or shorebirds if you’re on the coast. The US Department of Agriculture (USDA) recommends that anyone who cares for poultry “should prevent contact between wild birds and poultry by removing sources of food, water, and shelter that attract wild birds,” according to a USDA spokesperson.
Experts suggest that if you see potential signs of illness—like birds that are acting weirdly with a head tilted back, or walking in circles, or looking disoriented —you should keep your distance. Wear protective equipment like gloves and a mask if you need to handle them. Treat anything that’s sick as if it could be positive, even though there’s a good chance it’s not.
Right now, the risk to humans from the current outbreak of H5N1 is still very low. Since 2024, the Centers for Disease Control (CDC) has reported the number of infections in human cases of HPAI in the United States, and there is no evidence of person-to-person transmission at this time. As of March 6 2025, there are 70 reported human cases in the US, none of which are in PA or NJ. Sixty-five of these cases are from poultry or cattle exposure and five cases did not have an exposure source determined.
The consumption of raw foods, including raw milk and raw milk products, poses known risks of transmission and should be avoided by domestic cats and people.
Although the risk to the general population is low, the CDC states that individuals who work on farms, or closely with domestic animals or wildlife – whether backyard poultry owners, veterinarians or those with recreational exposures – are at increased risk.
It’s important to stay up to date with the latest guidance from local, state, and federal wildlife authorities. As officials monitor the virus, they may recommend temporarily removing feeders, avoiding certain habitat areas, reporting sick or dead birds, or taking other precautions.
Sources:
https://www.vet.cornell.edu/highly-pathogenic-avian-influenza-bird-flu-resource-center/avian-influenza-bird-flu-fact-sheet (Updated Feb 26, 2025)
https://www.cdc.gov/bird-flu/situation-summary/index.html
https://www.audubon.org/magazine/what-does-avian-flu-surge-mean-your-bird-feeders
https://www.audubon.org/magazine/winter-2021/how-feed-birds-safely-winter
