Avian Flu Threatens California Peregrine Falcon Nests
The HPAI virus is linked to a significant decline in peregrine falcon nesting activity across the California Channel Islands.
Updated on Oct. 24, 2026 in Bird Watching
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Peregrine falcon nesting sites across the California Channel Islands have experienced a notable decline since 2016. Wildlife experts suspect the Highly Pathogenic Avian Influenza H5N1 virus, which appeared in California in 2022, is a primary driver of this trend.
Why it matters
Peregrine falcons are highly vulnerable to the H5N1 virus and currently lack the ability to develop antibodies against it. Because they hunt waterbirds that carry the virus, they face a severe risk of fatal infection.
A 2022 survey found that only 38 percent of 32 inspected nesting sites were active, compared to 51 sites observed in 2016. Infected falcons typically die within one to three days of symptom onset.
The players
Peregrine Falcon
These birds of prey are known for their high-speed dives and have faced significant ecological pressure due to avian disease.
The details
Researchers believe peregrine falcons contract the HPAI virus by preying on carrier waterbirds that interact with domestic poultry. Exposed birds currently show no ability to develop antibodies, leading experts to expect continued susceptibility until the virus mutates or the birds adapt.
Timeline
51 individual peregrine nesting sites were observed on the islands in 2016.
A full survey of 32 nesting sites was conducted in 2022.
Two newly fledged peregrine falcons were observed near Scorpion Anchorage in mid-July 2026.
Culture Shift
This decline reflects broader concerns regarding the intersection of domestic agricultural practices and wild bird health. The situation marks a departure from post-DDT recovery efforts for the species, as new viral threats reshape the survival landscape of the California Channel Islands.
Bird watchers and outdoor enthusiasts in the region should remain aware that sightings may be less frequent as nesting activity fluctuates. Visitors are encouraged to observe wildlife from a distance to minimize stress on bird populations during this period of ecological strain.
The takeaway
Wildlife biologists continue to monitor nesting sites for signs of resilience against the H5N1 strain. Until the virus evolves or the falcons develop a natural defense, the status of these populations remains fragile.
Further reading
Learn more about local bird populations in the California Bird Watching section.
Source note: This article includes information reported by The Santa Barbara Independent.
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