Bald-faced hornets are a common sight across North America, recognized by their distinctive black and white markings. While their name suggests they are true hornets, they are actually a species of yellowjacket. Understanding the dynamics of their nests, including the number of individuals they house, is important for safety due to their highly defensive behaviors. These social insects construct intricate paper nests that can house a significant population.
Understanding Bald-Faced Hornet Colony Size
The number of bald-faced hornets within a nest changes throughout their single-season life cycle. Colonies begin with a single queen in spring, and their numbers gradually increase. Colony growth accelerates by mid-summer as new workers emerge. By late summer and early fall, the colony reaches its peak population.
A mature bald-faced hornet colony typically contains between 400 and 700 workers. Some reports indicate even larger colonies, potentially reaching up to 1,500 to 2,000 individuals in rare instances. The final size of a colony is influenced by several factors, including the availability of food sources, favorable weather conditions, and the age of the nest. Adequate nutrition and suitable temperatures support a larger and more robust colony.
Nest Characteristics and Annual Colony Development
Bald-faced hornets build characteristic aerial nests that are gray, paper-like, and often pear-shaped or football-shaped. They construct these nests by collecting wood fibers from sources like weathered wood or fences, chewing them, and mixing them with their saliva to create a durable paper material. Inside, the nest contains tiers of hexagonal combs where the young are reared. A single opening, usually at the bottom, serves as the entrance.
The annual life cycle begins in spring when a fertilized queen emerges from hibernation. She selects a suitable location (e.g., trees, shrubs, eaves) and constructs a small starter nest. The queen lays her first batch of eggs, and once these develop into workers, they enlarge and maintain the nest. Workers forage for food and care for young, allowing the queen to focus on laying eggs.
In late summer and fall, the colony produces new queens and males, which leave the nest to mate. With cold weather, the original queen, workers, and males perish. Newly fertilized queens hibernate to start new colonies the following spring. Nests are not reused and are abandoned by winter.
Safe Approaches to Hornet Nests
Bald-faced hornets are defensive and aggressively protect their nests. They can sting repeatedly and spray venom, especially if their nest is disturbed. Approaching an active nest can provoke an attack, posing a significant risk. Their sting is painful and can cause swelling.
Do not attempt to remove large or active nests without professional assistance. DIY removal is dangerous, especially for those with allergies. Observe nests from a distance and avoid disturbing the colony. If a nest poses a threat, contact a professional pest control service. Experts have the equipment and training to manage these situations.