The Western Black-Legged Tick is a common tick found throughout the west coast of North America. This species of tick is a vector of both the Lyme disease spirochete and Equine Granulocytic Ehrlichiosis Rickettsia in California.

Immature stages (larvae and nymphs) feed mostly on lizards (e.g. Western Fence Lizard) and small rodents while the adults feed on large mammals such as deer, dogs, coyotes, horses and humans. This species is most active from late winter to summer, with the immature stages feeding primarily during the spring and summer months.

Widespread Californian Tick. Life cycle can be completed in less than one year but usually lasts about two years. Females overwinter, laying eggs in the spring on the undersides of brush and dried leaves. Eggs hatch during early summer. Nymphs and adults seek hosts (quest) from the tips of vegetation while larval ticks find hosts close to the ground. Most commonly encountered Ixodestick in California. Adults occur year-round but are most commonly found November through May. Nymphs are most commonly found March through June but can be found year-round.

Immature stages commonly found on Alligator Lizards, Fence Lizards, and ground inhabiting birds. Sometimes found on small rodents and rabbits. Large mammals are also important hosts for larvae and nymphs. Adults are common on deer and other large mammals (dogs, bears, cats, horses, humans, etc.).

Potential Diseases: Vector of Lyme Disease. Has caused tick paralysis in a dog. Bites can cause painful sores.