UPDATE: LA County Veterinary Public Health ceased testing dead birds for West Nile Virus in 2020, but other agencies continue to test them. Learn more about reporting dead birds for WNV testing here. 

Did you know?

• 66% of dead birds tested for WNV in Los Angeles County in 2016 were positive for the virus (124 out of 188)
• The number of WNV-positive birds was highest in August, the peak of the WNV season.
• Most WNV-positive birds were in the western half of Los Angeles County (see map).
• The WNV season lasted from May to November, as shown by the number of WNV-positive birds increasing and decreasing in whose months, respectively (see graph).

What kinds of dead birds should I report for WNV testing?

Freshly dead crows, ravens, and birds of prey may be tested for WNV. 

How do I report a dead bird?

• Click here to read about reporting individual dead birds for potential WNV testing.

• Click here to read about reporting clusters of three or more sick or dead birds (or other animals) for potential testing here.

Why test dead birds for WNV?

Tracking WNV in dead birds helps show where the virus is most active in the county. It also helps show the start and end to the WNV season.

Learn more about WNV

• WNV in humans in LA County
• WNV in birds in LA County
• 2015 LA County dead bird WNV data
• 2016 West Nile Virus in Birds and Humans- combined - Epidemiology Report
• WNV throughout California

 Where does this data come from?

Members of the public report dead birds to various agencies in LA County and in California. Each dead bird is tracked, even when they cannot be tested for WNV. The Veterinary Public Health Program graphs and maps the LA County data from all participating agencies and shares it on this page. The dead bird testing effort has been in operation since 2004, the year after the virus first appeared in LA County. It has helped reveal shifts in the environmental epidemiology of the virus over the years. Testing was significantly decreased in mid-2013, and began to increase again in 2015. A vibrant dead bird testing program is an essential part of tracking the virus in our environment in LA County.

Last updated: January 25, 2024