Highly pathogenic H5N1 avian influenza is killing black vultures at alarming rates across the southeastern United States, with a new University of Georgia study finding that more than four out of every five dead vultures tested positive for the virus. The research, which examined 134 vultures collected from seven states, points to a species-level crisis driven by the birds’ own scavenging behavior. Because vultures feed communally on carcasses, including those of other infected vultures, the virus appears to cycle through their populations year-round, raising concerns about both biodiversity loss and potential spillover to other species.
An 84 Percent Infection Rate in Dead Vultures
The peer-reviewed study, published in Scientific Reports, tested samples from 134 black vultures found dead across seven southeastern states. Of those, 113 tested positive for highly pathogenic avian influenza, an infection rate of 84.3 percent. That figure is far higher than detection rates typically seen in other wild bird species during the ongoing H5N1 outbreak, and it suggests that black vultures face a uniquely severe threat from the virus.
The study was led by researchers at UGA’s Southeastern Cooperative Wildlife Disease Study, part of the University of Georgia and its College of Veterinary Medicine. Researchers warned that the actual toll on black vulture populations is likely exponentially higher than the sample reflects, since the 134 birds represent only a fraction of vultures dying undetected across the region. Tens of thousands may have been affected since the outbreak began spreading through North American wild bird populations in early 2022.
Scavenging Creates a Self-Reinforcing Cycle
What makes black vultures especially vulnerable is the same behavior that makes them ecologically valuable. As obligate scavengers, they clean the environment by consuming dead animals, but that diet also puts them in direct contact with infected carcasses. The UGA study found that year-round mortality occurred in black vultures in 2022, a pattern that may have been maintained by conspecific scavenging, meaning vultures feeding on the bodies of other vultures that had already died from H5N1.
This creates a feedback loop that most other bird species do not experience. Waterfowl, for instance, can carry H5N1 with lower mortality rates and spread it through shared water sources. Black vultures, by contrast, congregate in large communal roosts and feed together in tight groups on single carcasses. When one bird in a roost dies from the virus, others are likely to consume the remains, ingesting a high viral load. The Maryland Department of Agriculture flagged this exposure route as early as 2022, when sick and dead vultures in Harford County tested positive for H5N1 at a federal lab. State officials at the time noted that the birds had likely been exposed through scavenging infected material.
The vultures’ role as nature’s cleanup crew means they are repeatedly exposed wherever the virus is circulating in wild birds or backyard flocks. In landscapes where poultry operations, waterfowl habitat, and vulture roosts overlap, carcasses from one outbreak can quickly become a source of infection for another species. That connectivity is part of what has turned this H5N1 strain into a multi-year crisis for wildlife managers.
A Virus That Keeps Changing
The threat to black vultures exists within a broader pattern of H5N1 evolution in wild birds across the country. The U.S. Centers for Disease Control and Prevention tracks detections in wild birds and has documented the virus in every major flyway. Meanwhile, the USGS National Wildlife Health Center reported that two different genetic versions of the virus were identified in dead birds found in September 2025 at Horicon and in late September 2025 at Great Salt Lake. The identification of multiple genetic variants in separate locations signals that the virus is not static. It is evolving as it circulates through different bird populations and geographies.
For black vultures specifically, this ongoing evolution raises a question that current surveillance has not yet answered: whether the strains circulating in communal vulture roosts are diverging from those found in other wild bird populations. The UGA study documented infection across seven states but did not include detailed genomic sequencing comparing vulture-derived strains to those in other species. That gap matters because vulture roosts concentrate large numbers of birds in close contact, conditions that can accelerate viral mutation. No federal agency has yet published vulture-specific genomic data from the Southeast, leaving this risk poorly characterized.
Wildlife disease experts say that without sequencing from vulture carcasses, it is difficult to know whether the virus is adapting to this species in ways that might change its lethality or transmission dynamics. A strain that becomes slightly less deadly but more transmissible within vulture roosts, for example, could keep the virus entrenched in the population for years, with periodic die-offs instead of a single catastrophic crash.
Half May Survive, but Population Pressure Builds
One finding from prior research offers a partial counterweight to the grim infection numbers. Previous work from UGA scientists suggests that about half the vultures infected with bird flu survive. If accurate, that means the species has some capacity to weather the outbreak without collapsing entirely. But a 50 percent survival rate still represents enormous population pressure when applied to a species experiencing year-round exposure.
Black vultures are not endangered, and their populations had been growing across the eastern United States for decades before H5N1 arrived. That growth, however, does not guarantee resilience against a novel pathogen that kills at this scale. The UGA researchers’ warning that the true death toll is likely exponentially higher than the 113 confirmed positives in their sample should be read in that context. Wildlife disease researchers rarely have the resources to test every dead bird in a region, and vultures that die in remote areas or are quickly consumed by other scavengers may never be counted.
Even if overall numbers remain relatively high, repeated local die-offs can have ecological and social consequences. In some rural communities, black vultures are already a point of tension because of their occasional predation on newborn livestock. Large mortality events near farms or roosts can shift those dynamics, altering how people perceive and respond to the species. At the same time, losing vultures means losing a critical sanitation service, which can leave more carcasses on the landscape and potentially increase risks for other scavengers and domestic animals.
Federal Tracking and Its Limits
The federal government tracks H5N1 detections in wild birds through a system maintained by USDA APHIS, with data accessible through an online dashboard and periodic situation reports. These tools help identify where the virus is circulating but are not designed to provide detailed population-level assessments for specific wildlife species. Most entries simply record that a bird of a given species at a particular location tested positive, without follow-up on local mortality or long-term trends.
State agencies fill some of these gaps. In Maryland, for instance, information on avian influenza events is shared through official portals such as state government websites and the state agriculture department, which coordinate with federal partners on surveillance and response. But even with this layered system, the monitoring network relies heavily on reports from landowners, hunters, and members of the public who happen to encounter dead birds.
For black vultures, that means many outbreaks are likely going unnoticed unless they occur near populated areas or high-profile sites like wildlife refuges. A roost that experiences substantial mortality on private timberland, for example, might never be documented if carcasses are quickly scavenged or decay out of sight. The UGA study underscores this limitation by showing how much can be learned when researchers systematically collect and test carcasses across a wide region, work that is costly and difficult to sustain over multiple years.
What Comes Next for Black Vultures
Researchers say that protecting black vultures from H5N1 is not as simple as vaccinating a domestic flock or culling a confined group of birds. These are wide-ranging scavengers that cross property lines and jurisdictional boundaries daily. Any management strategy must balance disease concerns with the essential ecological role vultures play in removing carrion and limiting the spread of other pathogens.
For now, scientists are urging continued surveillance, better genomic tracking, and close collaboration between wildlife agencies, veterinarians, and landowners. They also emphasize the importance of reporting unusual numbers of dead vultures or other wild birds to local authorities, so that carcasses can be tested and emerging hotspots identified. As the virus continues to evolve and circulate among wild birds, the fate of black vultures in the Southeast will depend on how quickly researchers and managers can detect changes, and whether the species’ natural resilience is enough to withstand a pathogen that has already reshaped avian populations across the continent.
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*This article was researched with the help of AI, with human editors creating the final content.
