California Condor HPAI Response Update - April 28, 2023

On April 15, the U.S. Fish and Wildlife Service established an Incident Command Team to respond to the outbreak of Highly Pathogenic Avian Influenza (HPAI), also known as bird flu, in the Southwest (Arizona-Utah) flock of California condors. The Incident Command structure structure
Something temporarily or permanently constructed, built, or placed; and constructed of natural or manufactured parts including, but not limited to, a building, shed, cabin, porch, bridge, walkway, stair steps, sign, landing, platform, dock, rack, fence, telecommunication device, antennae, fish cleaning table, satellite dish/mount, or well head.

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facilitates additional support staff and promotes increased coordination amongst partner agencies. This structure is regularly used to respond to natural disasters and oil spills and allows officials to more nimbly and efficiently respond to such events. The Incident Command will provide updates in this format on a routine basis until further notice.  

Incident Response 

The Service, in collaboration with partner agencies, continues to monitor and respond to bird flu in condors. At the time of this information update, all confirmed HPAI positive condors have been found in northern Arizona. Bird flu has not yet been confirmed in the condor populations in Utah (the Southwest flock spans the Arizona-Utah border), California or Baja California, Mexico.   

Field teams have not collected a deceased or distressed condor in northern Arizona since April 11, 2023. New cases of HPAI appear to be in a downward trend in the Southwest flock, however officials continue to closely monitor the condors and are developing long-term strategies to protect the endangered species as the virus becomes more prevalent across the globe, with spikes expected during bird migration seasons.  

The Incident Command Team, along with partners and stakeholders, is working to enhance supportive care facilities, maintain sufficient support for field operations and monitoring, coordinate with USDA regarding potential vaccination of condors, and develop long-term strategies for potential future HPAI outbreaks.  

Status of HPAI in the Southwest Flock as of April 28, 2023 

To ensure maximum transparency and until further notice, the Service will disclose and report all deceased condors in the Southwest flock found on or after March 30, 2023, prior to necropsy and preliminary testing. As results are confirmed at the U.S. Department of Agriculture’s National Veterinary Service Laboratory, we will update their status as "confirmed HPAI." This information will be accessible at  We are not releasing individual identities of any deceased or recovering condors at this time. 

As we continue to share these numbers, we also want to provide some additional information to clarify why the number of deceased and confirmed birds will ultimately not match. The mortality count includes birds that are unrecoverable and will not undergo necropsy or testing for HPAI. Condors can be unrecoverable for various reasons including failing radio tags, difficulty pinpointing the exact location of a mortality signal, or inaccessible terrain. Additionally, rescued birds that are confirmed as HPAI positive will be included in the “confirmed HPAI positive” count. 

  • Total mortality: 20 condors  

  • Deceased and recoverable: 17 condors  

  • Deceased and unrecoverable: three condors 

  • Number of condors in care: four condors  

HPAI Results: 
  • Total condors tested: 21 condors  

  • Confirmed HPAI positive: 15 condors (four samples pending) 

  • Confirmed HPAI negative: two condors in care at Liberty Wildlife  

Breeding pairs impacted by HPAI:
  • Seven breeding pairs (11 individuals deceased) 

Response Tactics

Partners are caring for recovering birds, evaluating current care and quarantine facilities, identifying where improvements are needed and continuing to refine safety procedures for field crews.  

The four birds at Liberty Wildlife in Phoenix, Arizona, are showing signs of improvement. 

  • The first condor transported and admitted to Liberty Wildlife alive was ill with clinical signs consistent with possible bird flu. However, initial tests did not confirm the presence of the virus and subsequent testing using other laboratory techniques indicated this bird had been exposed to the virus.  

  • HPAI is no longer being detected in two birds initially confirmed with the virus, indicating they are recovering.  

  • One condor that was captured out of an abundance of caution after exhibiting lethargic behavior has never tested positive for HPAI. 

Partners are developing criteria to determine when it is safe to return the rescued birds to the wild based on their disposition and the current conditions of the flock. Captured birds are being tested for antibodies to determine if they develop some level of immunity to HPAI. 

The Peregrine Fund continues to lead daily operations of monitoring and management of the flock throughout the range and at various known gathering sites including the release site on the Vermilion Cliffs National Monument. Grand Canyon National Park and Zion National Park are monitoring portions of the flock within their respective management areas and have offered additional support as needed. All will continue to conduct rescue efforts to try and locate distressed condors and recover deceased condors 1) to ensure they undergo necropsy and testing for HPAI and 2) to remove infected birds from the landscape in hopes of reducing available disease vectors in the area. The Peregrine Fund is also taking actions to avoid the congregation of birds through discontinuing communal feeding sites and watering areas for the foreseeable future. We are evaluating when conditions will allow for condor releases to resume. 

The Peregrine Fund, with support from Arizona Game and Fish Department (and National Park Service as needed) is scheduling flights on a bi-weekly basis to monitor and track radio tagged condors throughout the range. The most recent telemetry flight occurred on April 27; no new mortality signals were detected.  

Free-flying condors go missing regularly and telemetry flights are one way to look for birds that have not been seen or detected recently. Across the range of the California condor, 20 condors went missing between 2020 and 2022. Currently, one such bird is condor 409, a well-known and well-loved bird in Zion National Park. Condor 409 was known for her success in raising two condor chicks that successfully fledged in Zion. She was regularly seen at her active nest until March 26. Biologists have been attempting to locate 409, but due to an aging and failing tracking unit, they have been unable to do so. The telemetry flight on April 27 did not reveal any new information and although we will continue to look for her, it is likely we may never locate her. Cause of death cannot be determined for missing birds, and they are recorded as “unknown”. Unknown birds are typically considered deceased after 365 days, unless field-based observations suggest otherwise.  

Vaccine trials  

The USDA’s Animal and Plant Health Inspection Service is leading this discussion and released the following statement: USDA APHIS has confirmed highly pathogenic avian influenza in endangered California condors. To protect this critically endangered species, the U.S. Fish and Wildlife Service approached APHIS to discuss the possibility of vaccinating the birds against HPAI. At this time APHIS and Service, along with state animal health officials, are exploring the logistics and use of a vaccine in that population.