Hanalei National Wildlife Refuge

Avian influenza has been recognized globally for decades and includes a range of virus strains, some of which have caused significant die-offs in wild and domestic bird populations and pose potential risks to human health. In recent years, a highly pathogenic form of avian influenza (HPAI) has spread widely across North America. Although the virus had been circulating extensively in the continental U.S. since its first detection in 2021 it had not been detected in Hawaiʻi until November 2024, leaving uncertainty in how Hawaiʻi’s endemic and native bird species would respond to this circulating strain of the virus. Since it’s first detection in Hawaiʻi, a total of 11 cases have been recorded in various duck species on Oʻahu and Maui, and fortunately it has not resulted in widespread deaths/outbreaks within the Hawaiian Islands thus far. While HPAI H5N1 originates from wild birds like waterfowl, domesticated birds remain the most impacted by the current strain.  This is consistent with what we have seen from the several detections of the virus in Hawaiʻi. 

A different disease, avian botulism, is a naturally occurring soil bacteria that produces a toxin that can be fatal for waterbirds. Since 2011, more than 1,600 sick or dead birds have been affected by avian botulism at Hanalei NWR and as such, our surveillance program consists of 30+ weekly surveys conducted by USFWS staff and volunteers. 

A sick koloa maoli (Hawaiian duck) was found on November 25, 2025 by a USFWS volunteer during a routine botulism survey in an area where we were responding to a botulism outbreak. The bird was treated for avian botulism and tested for avian influenza but died within 24 hours while in quarantine. The initial test result came back as “non-negative” for avian influenza and was sent to the National Veterinary Services Lab for confirmatory testing and to determine the exact strain of avian influenza. In early January, the final test results came back as positive for avian influenza, but there was not enough genetic material to determine the exact strain of avian influenza or if it was a form of HPAI. Given the botulism outbreak in the area at that time and similar paralytic symptoms, it is suspected that the duck died from botulism, while carrying avian influenza.  We are continuing to monitor for avian influenza by testing sick and dead birds, as well as live koloa maoli. The positive test result from the duck in November is the only positive result we have had since we began testing for avian influenza late last year.