Jeff Hahn, University of Minnesota
Size: 1/2 - 3/4 inch long
Description: Slender black wasps; smooth bodies with few hairs.
Where/When: Bird-nest wasps are associated with window cases, constructing nests made with grass. Nests are provisioned with katydids or crickets. They are active mid-summer to fall. Their nests may also be noticed during winter.
Significance: They are only a nuisance. They do not harm people or damage windows. They do not necessarily come back to nest in the same site the following year.