Due to the presence of a hard plate or scutum that completely covers the dorsal side of the male, they are unable to feed in large quantities.

[7][8] An unfed adult female is around 3.18 mm in size, has a brown-black scutum on the anterior back, an orange abdomen, and forward-projecting mouth-parts which enable feeding.

[10] Nymphal stage ticks prefer a habitat consisting of dense woodlands with many leaves and areas littered with fir needles.

It is most common to encounter western black-legged tick nymphs in areas with large amounts of shed leaves on the ground.

This life stage of the tick may be encountered when humans are in direct contact with logs, branches, and shed leaves.

As such, these ticks are commonly encountered in open grasslands, at the border of trails in parklands, and in areas that are able to maintain a deer population.

[11] Larvae, which emerge from eggs after approximately 53–55 days, take blood meals from vertebrates, such as lizards and birds.

[7] In order for the nymph to reach the adult stage, they continue to feed for 7–11 days on the blood of vertebrates.

Female adults will consume blood meals from medium and large-sized mammals, and then deposit eggs in areas of leaf litter or soil.

Due to the smaller size of the nymphal stage ticks, approximately 2 mm, they are more likely to go unnoticed when attached to a human.