Western Yellowjacket

Western Yellowjacket (Vespula pensylvanica)

This species is known for massive colonies that can reach 1000 to 5000 workers at peak size.
 

Geographic Region

Western yellowjackets are native to the western half of North America.
 

Natural Habitat

The majority of Western yellowjacket nests are found in abandoned rodent burrows, but have also been found in attics and building walls.
 

Weather Conditions

In warmer climates, entire colonies of Western yellowjackets can overwinter -- not just the queen.
 

Behavior

Western yellowjackets will scavenge for protein and sugar, becoming “picnic pests”. This species is known to create severe problems for loggers and fruit growers, as well as those engaging in outdoor recreational activities.
 

Unique Characteristics

Western yellowjackets share the same basic yellow and black pattern as other yellowjackets; however, sometimes they can be differentiated by a continuous yellow ring (called an “eye-loop”) around each eye.