Yellow jackets are predatory social wasps, known for their black and yellow markings. These insects are often encountered during outdoor activities, particularly in late summer and fall. Understanding their nesting habits aids awareness and safety, as they become aggressive if disturbed.
Primary Nesting Environments
Yellow jackets adapt to various sheltered nesting sites. Many species, such as the Eastern yellowjacket, predominantly construct nests underground, often repurposing abandoned rodent burrows or other soil cavities. These subterranean nests are often hidden in dense ground cover, hollow logs, or beneath railroad ties and concrete blocks. The entrance to a ground nest can be a small, inconspicuous hole, sometimes only nickel-sized, making it difficult to spot.
Other species, such as the German and aerial yellowjackets, prefer above-ground sites. These nests are common in protected areas of human structures, including attics, wall voids, sheds, and under eaves. They also build nests in natural above-ground locations like trees and shrubs. Some species, like the aerial yellowjacket, build conspicuous football-shaped nests attached to tree branches or buildings.
Distinguishing Features of Their Nests
Yellow jacket nests are made from a papery material, created by chewing wood fibers and mixing them with saliva. This forms a grayish-white pulp, creating a smooth, often wavy exterior. The paper’s color can vary depending on the type of wood fibers available in the surrounding environment.
Nests vary significantly in size and shape, often round or oval, some growing to basketball size or larger. Unlike open-celled nests of other wasps, yellow jacket nests are enclosed by multiple layers of this paper-like envelope. A single entry/exit hole is common, especially for ground nests, where wasps are observed flying in and out of a small opening.
Environmental Factors for Nest Building
Yellow jackets select nesting locations based on environmental factors for colony success. Adequate shelter from elements like rain and wind is a primary consideration, which helps maintain the nest’s structural integrity and internal temperature. This drive for protection leads them to choose concealed spots like underground burrows or enclosed structural voids.
Protection from predators also influences nest placement. Hidden locations offer a defense against animals that might disturb or destroy the colony. Proximity to consistent food and water sources is crucial, as workers forage within a certain radius, typically up to 1,000 feet from the nest. Availability of suitable building materials, like weathered wood for pulp, also plays a role. Yellow jackets prefer warm, dry spots, and the queen will choose a site in spring to initiate the nest, with the colony expanding throughout the summer.