Bald-faced hornets are common across Michigan, active from spring through late fall, and known for building large, football-shaped paper nests in trees and on structures. Despite the name, they aren’t true hornets at all. They’re a type of aerial yellowjacket, and North America’s only true hornet is the European hornet, an accidentally introduced species. That distinction matters little when you’re staring at a nest on your eaves, but it helps explain their behavior: bald-faced hornets are closely related to the yellowjackets that crash your backyard barbecue, just with different nesting habits and a more striking appearance.
How to Identify a Bald-Faced Hornet
The most obvious feature is the ivory-white pattern on the face, which gives the insect its name. White markings also appear on the thorax, legs, and abdomen, creating strong contrast against the mostly black body. Workers range from about 13 to 20 mm long (roughly half an inch to three-quarters of an inch), with the queen at the larger end of that range. They’re noticeably bigger than common yellowjackets and lack the bright yellow banding most people associate with wasps.
European hornets, which also live in Michigan, look quite different. They’re brown and yellow, significantly larger (up to an inch), and tend to nest in protected cavities like hollow trees or wall voids rather than building exposed aerial nests. If you see a large, gray, teardrop-shaped nest hanging from a tree branch or under a roofline, you’re almost certainly looking at a bald-faced hornet colony.
Yearly Life Cycle in Michigan
Every bald-faced hornet colony lasts only one year. There is no carryover from season to season, and old nests are never reused. The cycle starts in April or May when a fertilized queen emerges from hibernation, selects a nesting site, and begins constructing a small paper nest on her own. She raises the first batch of sterile female workers by herself, feeding them chewed-up insects mixed with saliva.
Colony growth is slow at first but accelerates through the summer as each new generation of workers takes over foraging and construction duties. By late summer, the nest can house 100 to 400 workers. This is when the colony is at its most visible and most defensive. In the fall, the colony shifts its energy to producing new queens and males. These leave the nest to mate, and the newly fertilized queens find sheltered spots to hibernate through Michigan’s winter. Everyone else, the workers, the old queen, and the males, dies when freezing temperatures arrive. By December, the nest is empty.
Where They Build Nests
Bald-faced hornets are aerial nesters. They favor tree branches, shrubs, building overhangs, utility poles, and occasionally playground equipment or porch ceilings. The nest itself is made of paper, a mix of chewed wood fiber and saliva that dries into layered gray or tan sheets. A mature nest is roughly the size and shape of a football or basketball, with a single opening at the bottom. Inside, the paper layers create insulated chambers with horizontal combs where larvae develop.
Nests are often high enough that people don’t notice them until the leaves drop in fall, revealing a structure that’s been growing all summer. Early in the season, a new nest may be only the size of a golf ball and easy to miss.
Aggression and Sting Risks
Bald-faced hornets are extremely protective of their nests. They’re more aggressive than honeybees when defending the colony, though less so than fire ants or Africanized bees. The critical distance is roughly 10 to 15 feet from the nest. Within that range, vibrations from a lawnmower, footsteps, or accidental contact with the nest can trigger a coordinated defensive response from multiple workers.
Unlike honeybees, bald-faced hornets have smooth, straight stingers. They can sting repeatedly without dying, which makes a defensive encounter with several workers at once a more serious event. Each sting delivers venom that causes pain, swelling, and redness at the site. For most adults, even multiple stings are painful but not dangerous. The average adult can physiologically withstand hundreds of stings.
The real danger is an allergic reaction. People who are allergic to wasp venom overproduce certain immune antibodies in response, which can trigger anaphylaxis, a whole-body reaction involving hives, difficulty breathing, throat swelling, and a sudden drop in blood pressure. If you develop widespread hives or shortness of breath after a sting, that’s a medical emergency requiring a call to 911. For non-allergic people, a cold pack to reduce swelling, an over-the-counter antihistamine for itching, and hydrocortisone cream on the sting site are usually enough. Watch for swelling that doesn’t improve after a few days or a red line extending from the sting toward your heart, both of which warrant a call to your doctor.
Their Role in the Ecosystem
Bald-faced hornets are predators. They hunt other insects, including flies, caterpillars, and other yellowjackets, to feed their developing larvae. A colony of several hundred workers actively hunting through the summer makes a meaningful dent in local pest populations. They also visit flowers for nectar, contributing modestly to pollination. In areas where they’re not near foot traffic or doorways, a bald-faced hornet nest is genuinely beneficial to have nearby.
Dealing With a Nest on Your Property
The first question is whether you need to do anything at all. A nest high in a tree, well away from foot traffic, will die off on its own by winter. Michigan State University Extension recommends warning family members and visitors to avoid the area and simply waiting for the colony to end naturally. This is often the best approach.
If the nest is near a door, walkway, play area, or somewhere people and pets regularly pass, removal becomes more practical. Professional pest removal companies are the safest option for large, established nests. Bald-faced hornet nests can contain hundreds of defensive workers, and a DIY attempt on a mature colony at head height or on a ladder carries real injury risk.
For those who choose to treat a nest themselves, early morning is the best time, when temperatures are coolest and the colony is least active. Aerosol wasp sprays that shoot a concentrated stream up to 15 or 20 feet allow you to maintain some distance. Follow the product label carefully and wear protective clothing. One important rule from MSU Extension: never plug the entrance to a nest built inside a wall or structure. Blocking the opening forces the hornets to chew their way into the interior of the house.
If you find a small, early-season nest the size of a golf ball with just a queen and a handful of workers, it’s far easier to remove at that stage than waiting until August when the colony has grown to full strength. A garden hose on a jet setting can knock down a small exposed nest from a safe distance.