Colorado Parks and Wildlife (CPW) is warning the public about the return of avian influenza across the state.
Also known simply as bird flu, highly pathogenic avian influenza (HPAI) is transmitted between bird species but can infect other animals, including humans.
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The virus spikes in the fall and early winter due to migrating birds moving through the area. It’s especially contagious among waterfowl like ducks and geese. Experts say this is because these birds tend to congregate near bodies of water.
Infected birds are known to act “strangely” and appear to be stumbling around, swimming in circles, struggling to fly or showing a swollen head. The virus is deadly.
“It can be really kind of scary to see birds acting in this unnatural way,” said Kara Van Hoose, CPW’s Northeast Region Public Information Officer. “We want people to know that this is something that happens to birds in Colorado. It's unfortunate that this strain has such a high mortality rate, but it's something that we're monitoring.”
While humans can contract the virus, it is rare. Since May 2024, the Colorado Department of Public Health and Environment has documented ten cases in the state. Health officials say the majority of those sick with avian flu experience flu-like symptoms. There were no reported deaths.
A larger impact seen last year was a hit to the production of eggs. Last year, Sen. Hickenlooper met with chicken farmers after avian flu killed off chickens and damaged more than 60% of egg production in the state.
The most recent strain of HPAI was found in 2022, and wildlife officials have tracked it ever since.
This year, CPW is focusing its messaging on domestic animals, such as people taking their dogs for a walk near a lake or pond.
“So you really have to be sure that you're keeping that distance between yourself and wildlife that looks sick or injured,” said Van Hoose. “This is something we tell you year-round: don't let your pets interact with wildlife because of the risk of disease transmission. Just keep up those same wildlife principles that you should already be practicing.”
While bird flu has been recorded across the country, the numerous rivers and watersheds in Northern Colorado attract large numbers of migratory birds and, as a result, lead to more positive detections of avian flu.
“We all see the geese that stay and the ducks and so on that move through, and for the last four years, it's been fairly extensive,” said Jackson Davis, a CPW district wildlife manager in Weld County. “This year, once we had that cold snap around Thanksgiving, we really started seeing an uptick in cases to the point where just in the Greeley Windsor area, it's pretty common for me to get four to five calls a day right now, if not more, on a sick or dying goose. And that will continue to compound as the migration continues.”
Wildlife managers are the people in charge of responding to calls of sick or injured wildlife. They test dead birds for avian flu when they think it is necessary or if there is a large number of dead birds in one area. They say that while they appreciate people’s efforts to help sick wildlife, they recommend keeping a safe distance and calling a professional.
“We've had plenty of zoonotic diseases that are transferred into humans in the last handful of decades, let alone the last handful of years,” said Davis. “If you’re noticing something odd or off or something just doesn't seem right, give us a call before you try and get hands on it, because the last thing we want to happen is have someone get sick.”
CPW’s wildlife number is 303-297-1192. You can also reach out to local offices on the agency’s website.
