Birds play a central role in the WNV transmission cycle. If an infected mosquito feeds on a bird and transmits WNV, the infected bird can then serve as a reservoir of WNV to other mosquitoes. Many bird species are susceptible to WNV and die as a result of infection; for example, American Crows and California Scrub-jays have a high mortality rate once infected. A positive dead bird is often the first indication that WNV is present in an area.

To report a dead bird, please call the WNV and dead bird call center (toll free number: 1-877-968-2473; 1-877-WNV-BIRD) at the Vector-Borne Disease Section, California Department of Public Health (CDPH). Open five days a week during the WNV season (approximately mid-April to mid-October). Hours are 8 am t 4:30 pm, M-F, with Sundays added during peak season. The public can also report dead birds online: www.westnile.ca.gov.