Officials: Avian flu to impact Spring migration
ALAMOSA — According to figures compiled by the USDA and Colorado Department of Agriculture, Colorado reported the loss of 6.26 million domestic birds in 2022 to the Highly Pathogenic Avian Influenza (HPAI), also known as avian flu.
But the devastation does not end there. HPAI is also killing wild birds in increasing numbers.
“This has been the largest outbreak in Colorado and the nation, ever,” Olga Robak, communications director for the Colorado Department of Agriculture, reportedly said in December.
And it is not likely to end soon.
In fact, according to Colorado State Veterinarian Maggie Baldwin, “With wild bird migration beginning soon, we anticipate that we will see an increase in virus activity through late winter and spring.”
With thousands of Sandhill cranes migrating to the San Luis Valley in about a month, the Valley Courier reached out to the Colorado Parks and Wildlife (CPW) to see what impact HPAI might have on the birds who are a celebrated part of the Valley landscape every spring along with the abundance of other birds who grace the Valley’s skies.
“Unlike prior strains of HPAI in North America, this particular strain is causing widespread mortality in some species of wild birds, particularly in snow geese, raptors and vultures,” says John Livingston, CPW’s Southwest Region Public Information Officer. “Across the state, we’ve seen a variety of hawks, ducks, geese, magpies, crows, and turkey vultures test positive. We have yet to detect HPAI in Sandhill cranes, at this time.”
As Livingston describes it, an outbreak of HPAI involving a new strain of H5N1 emerged in North America in the winter and spring of 2021-2022. Now, almost a year later, avian influenza outbreaks in wild birds and poultry continue to rise at a national level, and the U.S. is approaching a record number of birds affected compared to previous bird flu outbreaks.
“To date, HPAI has been detected in all four North American migration flyways,” he says, going on to echo the state veterinarian. “It’s expected that the disease will persist through spring migrations.”
For context, a few months ago, there were several incidents that provide a sobering glimpse of what is possible with the virus.
In late November 2022, CPW began receiving increasing reports of sick and dead snow geese in northeastern Colorado associated with large-scale HPAI mortality events. Staff with CPW recorded the deaths of close to 2,000 birds on multiple waterways in Morgan and Logan counties.
Shortly thereafter, large-scale deaths began occurring in southeast Colorado in Kiowa, Bent, Otero, and Prowers counties. Livingston says there was a die-off of approximately 600 snow geese at John Martin Reservoir, and CPW has observed a lower level of die-off at most reservoirs in the Lamar area.
“We have continued to see positive cases of this avian flu in every corner of the state, though in fewer numbers than those other mass events,” he says.
HPAI is also largely fatal to raptors — such as eagles, hawks, and owls — who become sick after feeding on the carrion of infected birds or by coming in contact with their feces or saliva.
Bald eagle deaths caused by HPAI have been found in four Colorado counties, including Adams, Boulder, Douglas, and Larimer.
When asked about the impact on raptors in the San Luis Valley, Livingston — who is stationed in Durango — offered a slightly brighter picture of the current situation.
“So far, we’ve felt pretty lucky in the Valley and across Southwest Colorado in that we’re not seeing a high-level of raptor mortality related to HPAI,” he said. “While folks have seen bald eagles eating the carcasses of Canada geese that have died of avian flu, we have yet to find or have reported to us a bald eagle death related to HPAI in our area.
“But we did have one great horned owl in Rio Grande County test positive for HPAI. Our only other HPAI positives in the Valley have been from Canada geese,” he added.
When asked to speculate about the coming months, Livingston declined, saying that is difficult, “especially in populations such as snow geese where populations have been thriving and absolutely booming in some areas.”
The wild birds CPW staff see most affected continue to be snow geese, vultures, and raptors.
“But, as the sandhill cranes migrate through the Valley this spring, we’ll certainly monitor to see if there are any impacts and what kind of effects HPAI has,” he said.
Livingston continues to look at the bigger picture.
“As the state wildlife agency, we manage with the best available science and will make fact-based decisions and avoid making speculations,” he said. “While it’s difficult to see any dead animal, Colorado and North America as a whole have made incredible strides in wildlife conservation to bring numerous species back from the brink of extinction in the 1800s and early 1900s to the place where wild birds and wildlife thrive and expand their population every year. Sound conservation practices and laws related to the protection of wild birds will be of benefit as we navigate the HPAI situation.”
In the meantime, Livingston offers some general instructions to the public.
“If you find three or more dead wild birds in a specific area within a two-week period or if you see live birds showing clinical signs of disease, please contact the local Colorado Parks and Wildlife office in Monte Vista. Please be aware that CPW will not be able to respond to all calls and is focusing responses based on surveillance and management priorities,” he said.
There has only been one documented case to date of a person becoming infected by the virus. That case, which happened in Colorado in April of 2022, was detected in a man who was working with infected domesticated birds. He suffered only mild symptoms and recovered fully.
Even so, Livingston offers a precaution.
“Although rare, some HPAI strains can infect people, so it’s important to protect yourself,” he said. “The main protection for the general public is to avoid handling sick or dead birds and keep your distance from wildlife.”
According to a fact sheet on the CPW website, the current strain causes disease in many species including swans, gulls, geese, grebes, pelicans, raptors, vultures, cranes, some species of ducks, turkeys, and other game bird species.
Typical symptoms include swimming in circles, moving slowly, incoordination (may appear drunk), and head tilt or inability to lift the head. Most affected birds are seen on the ground, but occasionally sick birds may be seen flying low and alone.
Additional background information and precautionary measures can be found by going to https://cpw.state.co.us/Documents/Wildlife-Health/HPAI-highly-pathogenic-avian-influenza.pdf.