Friday, August 28, 2009

Secretive Summer Residents: Bald-Faced Hornets in the Backyard

Last week, the setting sun illuminated secretive tenants hidden among the trees of my backyard. I was sitting with the sun behind me, watching the dusk clouds in the east. That’s when I suddenly noticed a large, pendulous, white football suspended in the branches of the young hemlocks growing among the garden beds.

Apparently, even though I walk around (and occasionally crawl under and through) these very trees, I never noticed my quiet new neighbors who crafted a summerhome above the dog trail to the water-bucket. I’m guessing they’ve been working there since Spring, and I suspect that the tipping point of their decision to set up shop was the hot weather, which heralded the arrival of a kiddie pool.

My new friends are the Bald-faced hornets (Dolichovespula maculata), closely related to the yellow-jacket wasps. Bald-faced hornets are impressive, and intimidating (hence why I don't have a close-up shot of an individual to share). I’ve seen them playing in the mud around the kiddie pool, and they share space with the local wild bumblebees and honeybees on the sunflowers and other blossoms.

I’ve noticed that they like the yellow ragwort (genus Senecio), the delicate Queen Anne’s lace (wild carrot, Daucus carota), and another white wild flower whose name I don’t know yet, but I encourage in the gardens (if you know its identity, please tell us in the comments).

Bald-faced hornets are amazing to watch at work: every few seconds someone flies in, and someone flies out. Sentries sit as inconspicuous bumps on the perimeter of the nest. In total, the nest is probably about 40-50 cm long, with at least one opening (visible in these photos).

According to articles I’ve read, the bald-faced hornets will ignore me if I keep my distance and do not disturb the nest - which seems to be their preference considering how long they've gone unnoticed. Now I’m taking advantage of the opportunity to watch them work.

Once the snow sets in this winter, I’m going to carefully cut down the nest so I can examine it up close. According to my research the bald-faced hornets will be finished with their mating cycle in the autumn, and they should leave the nest with plans to build a fresh home next season (so I won't have to feel bad about robbing them of their hard-earned resources in order to satisfy my curiosity).


  1. I just wanted to say that I am new to your blog and had gone and read some past posts. What caught my eye is that we became keenly aware of the importance of trees after a fall ice storm took down or damaged thousands of trees in Buffalo including trees on our property.

    Unlike many who hired any guy with a chain saw, we got a certified arborist to help and 3 years later, you can see the difference. We are now trying to see if we can save some of our ash trees from the ash borer with injected treatment. People don't know yet that this is going to be devastating.

    Sorry..I went on. Anyway, I am going to follow your blog as I want to learn more.

  2. Hi Michelle, and welcome! Thanks for sharing a bit about your personal process of connecting with your local environment.

    It's amazing to see how much activity occurs in our backyards, and to learn to actively engage with the ongoing process of destruction and renewal (of which trees are a crucial part).

    Of course, I've found that blogs are an especially a cool way to create a sort of virtual-back-yard-network! Thanks for visiting Arboreality, stop by any time.


  3. Bald face hornets are not a good thing for my work, in the Portland landscape scene. I see them maybe once a year. But it's still amazing how they build their homes and have their part in nature. They just need their space.

    M. D. Vaden Portland Landscape Design & Trees


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