California Condor HPAI Response Update - May 26, 2023

The U.S. Fish and Wildlife Service’s Incident Command Team, in collaboration with partner agencies, continues to respond to Highly Pathogenic Avian Influenza (HPAI), also known as bird flu, in the Southwest flock of California condors.

Partners and stakeholders have initiated vaccine trials and are working to improve the ability of flock managers in swiftly responding to potential future HPAI outbreaks through management of the flocks, and facility and infrastructure improvements. The Incident Command will provide updates on the incident in this format on a routine basis until further notice.

Incident Update

On May 16, HPAI vaccination trials began with 20 vultures and eight controls as surrogates for the condor to determine safety and effectiveness of the vaccine. All vultures that received the vaccine appear to be in good health with no vaccine site reactions. A blood draw was conducted this morning, May 26, as part of a preliminary check and will be analyzed at the USDA’s Southeast Poultry Research Center for HPAI antibodies to evaluate immune response. It is too early to detect effectiveness of the vaccine, but we hope to observe some level of immune response.

Depending on the results of this trial, the second step will be to implement the trial on 25 captive California condors. Trial design was collaboratively developed by the Service, USDA APHIS and U.S. Geological Survey.

Status of HPAI in the Southwest Flock as of May 26, 2023

Changes are indicated in bold in our reporting below.

  • Total mortality: 21 condors
  • Deceased and recoverable: 17 condors
  • Deceased and unrecoverable: four condors
Breeding pairs impacted:
  • Eight breeding pairs (13 individuals deceased)

  • Number of condors in care: five condors
HPAI Results:
  • Total condors tested: 21 condors
  • Confirmed HPAI positive: 19 condors (17 deceased, two in care at Liberty Wildlife)
  • Confirmed HPAI negative: two condors in care at Liberty Wildlife
Vaccination trials:
  • Birds vaccinated: 20 vultures


Field Operations

Field monitoring continues to ensure the Arizona-Utah flock remains healthy.

Rescued condors 757, 982, 1061 and 1108 are in care at Liberty Wildlife and partners will determine when it safe to release them back in the wild.

Flock managers across the range of the California condor are adapting strategies to avoid congregation of birds through discontinuation of communal feeding sites and watering areas.


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