Highly Pathogenic Avian Influenza (HPAI) in Wild Birds, including Owls and other Raptors
What we know as of April 15, 2022
by Lauren Smith
You may have been hearing and reading about a very contagious strain of avian influenza that is currently spreading across North America. I have been reading heartbreaking articles about raptors and owls being brought to wildlife rehabilitation centers in distress, suffering from extreme neurological symptoms and either dying suddenly or needing to be humanely euthanized.
Some recent examples:
The disease is 90 to 100% fatal in raptors, according to the University of Minnesota’s Raptor Center. Raptors may not show any symptoms or signs of infection until right before they die.
HPAI has been confirmed in Montana (on April 8, 2022) and all our neighboring states: Idaho ( on April 15, 2022), Wyoming and North Dakota (on March 30, 2022), and South Dakota (on March 6, 2022). It has also been found in wild birds in every province in Canada including British Columbia, Alberta, and Saskatchewan, which border Montana to the north.
We here at ORI have not yet (as of April 15, 2022) seen anything that makes us suspicious in any of the owls we study in the wild here in NW Montana, but we are keeping a close eye out for anything unusual. When we do handle wild birds, our research protocol includes measures to mitigate the potential contamination or spread of disease between birds. All of our research is done on wild birds; we are not a rehab facility and do not keep or care for any captive birds.
ORI has close relationships with several raptor and wildlife rehabilitation centers in the area, and if we find a bird we suspect is ill we will immediately take it to receive care, if possible.
What is HPAI?
Highly Pathogenic Avian Influenza (HPAI) is a virus. There are many different strains, and some of them are more dangerous than others. The different strains of the virus are classified as either ‘low pathogenic’ or ‘high pathogenic,’ depending on how good they are at making domestic poultry sick.
The current strain affecting all of North America is “Eurasian strain (EA) highly pathogenic avian influenza (HPAI) H5N1.” Most of the coverage you’ll read about it may call it simply avian flu, or HPAI.
The different strains of avian influenza are found mainly in waterfowl, like geese, ducks, and swans. Normally, these birds can carry the virus without any symptoms, and don’t seem to be badly affected by it. However, when poultry become infected, it causes high mortality.
How is it spread?
HPAI spreads in the feces and respiratory secretions of infected birds. It can also be easily transmitted on contaminated objects (an issue for poultry farmers, who can carry it on boots, clothes, or equipment). According to The Raptor Center at the University of Minnesota, HPAI can survive in aquatic environments as well as in cold and freezing temperatures.
Wild songbirds can carry the disease, but that may or may not mean you need to take down backyard bird feeders. This article by Korie Dean in The News & Observer in North Carolina is a good read for more information: “With avian flu in NC, is it safe to put out bird feeders? The answer is complicated.”
However, this article doesn’t mention that raptors can and often do hang out by bird feeders to catch songbirds. If you know you have local raptors that like to stake out your birdfeeders, you may want to take that into consideration.
Side note: Remember that right now (April) is the time of year when bears are coming out of hibernation, so if you live in bear country like we do here in the Mission Valley of Montana it’s a VERY good idea to take down and secure anything that a bear might find tasty, including bird seed. Avoid creating food-conditioned bears, which is leading to more and more human-bear conflict. See: “The problem of the urban bear,” by Amanda Eggert for the Montana Free Press, October 27, 2021).
Raptors, owls, and scavenging birds like gulls, ravens, and crows can become infected after eating infected birds. HPAI is often fatal for raptors and scavenging birds.
Symptoms of HPAI in raptors
The most common symptoms are neurological signs. Some of these are:
Apathy
Difficulty breathing
Head tilted at an angle
Leg/wing paralysis
Tremors
Inability to stand or fly
Arching of back
In infected raptors, symptoms may not appear until right before death.
This information comes from The Raptor Center. See their Avian Influenza website for a curated list of resources, commonly asked questions, and webinar recording for more information.
What we know- some stats:
According to data on the CDC website that was last updated on April 8 (see: Bird Flu Current Situation Summary), HPAI has been detected 637 times in wild birds (including raptors and owls) in 31 states.
This map from the National Wildlife Health Center is more updated (April 14, 2022), but it’s missing data (such as this data from the wild birds tested in Wyoming). However, the CDC makes it easy to download the data in an Excel, which I did because I was curious about a few things and wanted to poke around in the data.
Note: I downloaded and looked at this data on April 15, 2022.
Wild Bird Mortalities reported to USDA and APHIS (last updated April 8, 2022)
Species | number dead | states reported
Bald Eagle | 36 | Florida, North Carolina, South Carolina, Kansas, Pennsylvania, Minnesota, Vermont, Maine, Ohio, Wisconsin, Nebraska, Georgia
Cooper’s Hawk | 2 | Wisconsin, New York
Great Horned Owl | 5 | Minnesota, North Dakota, South Dakota, Florida (this number should be much higher, and also include at least Wyoming, if not more states)
Red-Shouldered Hawk | 1 | North Carolina
Red-tailed Hawk | 5 | Massachusetts, Iowa, Wisconsin, South Dakota, Kansas
Snowy Owl | 5 | New Hampshire, Michigan, New York, North Dakota,
Turkey Vulture | 1 | Massachusetts
Black Vulture | 32| Florida
Total: 84 birds
The other 581 birds in the data were waterfowl or water-associated birds: ducks, swans, pelicans, geese, heron, gull, sanderling.
For more information:
Avian Influenza- a website put together by The Raptor Center at the University of Minnesota with
NPR, April 9, 2022- “A worrisome new bird flu is spreading in American birds and may be here to stay”
How do scientists study avian influenza in wild birds? – FAQs and more information from the United States Geological Survey
Avian Influenza- information from the USGS National Wildlife Health Center
Data
Highly Pathogenic Avian Influenza (HPAI) in Wild Birds in Wyoming- map from Wyoming Game and Fish Department- Wildlife Health Laboratory showing locations and some basic information about HPAI positive birds
2022 Detections of Highly Pathogenic Avian Influenza in Wild Birds- USDA Animal and Plant Health Inspection Service
Bird Flu Current Situation Summary- information from the CDC. Includes data on detections in wild birds, poultry, and humans, and more useful information such as protective actions, what to do if you find a dead bird, and more.
