Wasp Nests

By Natural Resources Commissioner Pam Otto

What comes to mind when you think of a good neighbor? State Farm? The folks next door? Bald-faced hornets?

Okay, that last one may sound like a stretch. After all, aren’t hornets the critters people get “mad as”? Isn’t “stirring up a hornet’s nest” the last thing you want to do?

At this time of year, many St. Charles residents are seeing those nests—gray structures the size of a football, basketball or beachball—and worrying that they will indeed begin to stir again in springtime. Fear not! The insects that lived there peaceably throughout spring, summer and fall have perished, frozen by winter’s chill.

The nest and its contents, though, provide great benefit to other wildlife. Here’s a quick look at the facts about this common yet greatly misunderstood feature of our local landscape, and the architects that build them:

  • Bald-faced hornets aren’t hornets, but rather a type of paper wasp. They measure around 3/4 inch in length, and their markings are black and ivory (“bald” in this sense means white).
  • At their peak in summertime, the nests hold about 400 adult wasps—less than 1/10 of the population of a typical honey bee hive.
  • The nest will not be reused by the wasps, nor will any wasps survive the winter.
  • The frozen larvae and adults are a great source of winter protein for birds like chickadees.
  • Once torn open for food, the nest will start to break down and wear away in the elements.
  • Birds like red-eyed vireos use the paper from old nests to construct their own nests in spring.
  • In warmer months, bald-faced hornets help keep insect populations in check. They feed many types of insects to their developing offspring, and are especially fond of flies and even other species of wasps.
  • Adults feed primarily on nectar. In the process, they pollinate the flowers where they are feeding.

Next time you’re out and about, scan the bare branches of nearby trees for large, gray sportsball-shaped objects. When you see one you’ll know that, like a good neighbor, the bald-faced hornet was there.