Larvae found in tule swamps and ponds. Peak biting activity occurs in shaded or heavily vegetated areas during daylight hours and dusk. Flight range is less than two miles.

Primary hosts are birds and small mammals. Will bite humans if available.

Western Equine and St. Louis Encephalitis virus, and Turlock virus have been isolated from California populations. Calif. Encephalitis virus has been isolated from Utah populations. Secondary vector of West Nile Virus.