Highly pathogenic avian influenza was the primary underlying cause of the decline and death of Jackie, the Big Bear Valley bald eagle, according to a new necropsy and laboratory testing announcement from the California Department of Fish and Wildlife.
The findings add a medical explanation to a case closely watched by the public. Veterinary pathologists at the San Diego Zoo Wildlife Alliance conducted the necropsy, with additional diagnostic and toxicology work involving the agency and the Ojai Raptor Center.
What the necropsy found
Officials said the virus produced an uncommon presentation: a severe ulcer in Jackie’s ventriculus, the muscular part of a bird’s stomach often called the gizzard. The ulcer led to persistent internal bleeding, severe anemia and bacterial sepsis, according to the CDFW announcement.
Testing found HPAI genetic material in several tissues, including the ulcerated ventriculus tissue. Pathologists also identified severe inflammation and blood clot formation in the heart and major blood vessels. The agency described the illness as multiple severe, interconnected disease processes developing over time.
Testing was negative for West Nile virus. Lead and other heavy metals were within acceptable limits and were not associated with the disease progression. Brodifacoum, an anticoagulant rodenticide, and persistent environmental contaminants were detected in the liver, but the necropsy did not find the uncontrolled bleeding pattern associated with anticoagulant-rodenticide poisoning. Officials therefore did not identify brodifacoum as the primary cause of illness or death.
What it means for Shadow and the eaglets
Jackie’s mate Shadow remains in Big Bear Valley. Based on camera data, the agency said it had no evidence that Shadow or the eaglets were sick. That is not the same as a veterinary diagnosis, but it means the announcement did not report illness in the remaining nest family.
How can bald eagles be exposed to avian influenza? CDFW says waterfowl and shorebirds are natural hosts of avian influenza viruses, while eagles and other raptors may be exposed through contact with infected birds or by eating infected prey.
Jackie’s remains were cremated under established procedures intended to prevent HPAI transmission. The results also explain why her anemia persisted despite treatment: the underlying viral disease and the stomach injury were driving continued blood loss and secondary infection.