Actual Size: ½” to 1”

Characteristics: Black or dark brown, usually with yellow markings.

Legs: 6

Antennae: Yes

Habitat: Paper carton nests made up of chewed cellulose found in the ground, eaves, or attics


  • Social insects that live in colonies with up to 4,000 workers
  • Most active and aggressive in late summer when colony populations peak
  • Can be attracted to sweet, sugary foods as well as fragrant perfume

Yellowjackets in The North Bay and East Bay of California

Yellowjackets are aggressive stinging insects that are commonly encountered in the summer and fall. They are likely the most known wasp. The coloration varies by species, but the most commonly encountered yellowjackets typically have abdomens that are banded with yellow and black. Their legs are yellow in color. They feed on insects including caterpillars, flies, and other flying insects. As colonies increase, they are attracted to sweet foods consumed by humans. These beneficial wasps live in colonies with thousands of individuals and would be a lesser threat to humans were it not for their opportunistic behavior of nesting in structural voids, attics, and cavities associated with landscaping features.

Yellowjacket Habitat

These wasps nest both below and above the ground. Yellowjackets can be found anywhere humans are found, and nests are constructed of layers of comb made of tiny bits of wood fiber chewed into a paper-like pulp. Yellowjacket nests can be found in many different places in or around a home, including the ground, hollow trees, shrubs, bushes, or internally in attics, hollow walls or flooring, sheds, under porches, or eaves of buildings. Their underground nests can be in abandoned burrows from other types of animals and insects. Thousands of yellowjackets can be underground! When disturbed, yellow jackets are quite aggressive and can attack in large numbers.

Yellowjacket Behaviors, Dangers or Threats

Yellowjackets are capable of stinging repeatedly and will do so when they feel threatened or defending their nest. They get especially aggressive in the late summer and fall months when their colonies grow and resources begin to dwindle. This is when they are especially attentive at outdoor barbecues, picnics, and more, searching for sweet substances to feed on. Some individuals are more sensitive than others, due to allergic reactions, and should seek medical attention when stung.

If you notice a yellowjacket problem in or near your Bay Area home, always contact your local wasp removal experts.