Colorado winter bird migration carries increased risk of avian flu exposure to wildlife, domestic animals
State wildlife agency warns people to avoid sick wildlife
Colorado Parks and Wildlife/Courtesy Photo
As migrating bird populations begin to travel through Colorado during late fall and winter, Colorado Parks and Wildlife expects an increase in wild birds infected with highly pathogenic avian influenza.
The state wildlife agency issued a press release on Dec. 10, warning Coloradans to avoid sick wildlife.
Waterfowl and shorebirds are particularly susceptible to avian influenza transmission, as they will gather in large numbers around bodies of water, which facilitates the spread of the virus.
High path avian influenza has been a concern among domestic and wild birds in the United States since 2022, when it was detected in a commercial U.S. flock. By the end of 2022, there were detections in all lower 48 states, whether in wild birds, commercial flocks or backyard flocks.
It has impacted nearly 10 million domestic birds in Colorado since 2022 and 127 million nationwide, according to the state’s Department of Agriculture. The strain detected causes high mortality rates in wild and domestic birds with no known cure or treatment.
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Colorado had a spike in outbreaks last summer, with confirmed cases in poultry, dairy cattle and humans. This year, the state has not seen domestic poultry detections since March; however, there have been multiple detections of high path avian influenza in Colorado wildlife this fall.
In the press release, Peach Van Wick, Colorado’s state wildlife veterinarian, said that Parks and Wildlife has confirmed cases of the disease in fewer than 20 birds, one black bear and one bobcat.
Van Wick added that these confirmed cases are “likely an underestimation of the number of affected animals on the landscape.”
“This strain of HPAI has the potential to cause large-scale die-offs in wild bird populations as we progress into winter,” Van Wick said.
Birds infected with high path avian influenza may be moving slowly, swimming in circles, unable to fly, or found dead. They may also demonstrate a lack of coordination or have a swollen or tilting head.
Parks and Wildlife will test sick or dead birds for the presence of avian influenza when appropriate or when large die-offs are found in a new location. The public is encouraged to contact Parks and Wildlife if three or more birds exhibit symptoms or are found dead in the same localized area.
Similar symptoms are found in wild mammals that have tested positive for this strain of bird flu. This includes walking in circles, demonstrating a lack of coordination or appearing lethargic. As these neurological symptoms are consistent with rabies — a significant public health risk — Parks and Wildlife issued a warning that humans should never approach a mammal acting abnormally and report the behavior.
High path avian influenza can spread to domestic animals, including poultry, livestock and pets. To avoid infection, Parks and Wildlife reminds individuals to prevent pets from consuming or interacting with sick or dead wildlife and contact a vet if exposure is suspected.
Although extremely rare, humans may be infected with high path avian influenza. To avoid exposure to the virus, never handle sick or dead wild birds and do not approach wildlife.
Parks and Wildlife encourages waterfowl hunters to wear proper protection while handling or processing wild game, disinfect equipment thoroughly, keep wild carcasses away from domestic poultry and pets and cook game to an internal temperature of 165 degrees.
Veterinarians, producers and hobby poultry owners should report any suspicious disease events in domestic poultry flocks to the Colorado state veterinarian’s office at 303-869-9130.
