Adult activity peaks in the summer months. Breeds in natural and man made polluted waters. Feeds primarily on birds but may rarely bite humans. May transmit St. Louis Encephalitis.
Adults are active in June and July. Breeds in fresh water with cattails and tules. Feeds on large mammals, including humans, after sunset. Transmits encephalitis viruses.
Adult activity peaks August–September. Larvae live in hollowed out tree cavities and man-made containers. Prefer to feed on birds. Not considered a vector or a pest due to its limited distribution in San Mateo County.