Winter Searching for Paper Wasp and Yellow Jacket Nests
An aerial paper nest made by yellow jackets. (Photo: Karen McDonald)
Exploring Paper Wasp Nests (and yellow jackets too!)
Winter is the perfect time to look for things that are typically hard to see when trees are in leaf. This includes birds, mistletoe, and wasp nests. It's not unusual to see yellow jacket nests that are grey, round, and large in the upper branches of trees, but how much do we really know about paper wasps and yellow jackets? Are they still in there over the winter? Is it safe to approach? Let's look at these fascinating creatures in more detail.
Both yellow jackets and paper wasps are arthropods (joint-foots), in the order Hymenoptera along with ants and bees. They are also in the same Family Vespidae but in different genus and species. There are about twenty two species of paper making and building wasps in North America but it's thought that there are over 1,000+ world wide. This includes bald-faced hornets, which are a genus of yellow jackets also found commonly in North America.
The key characteristic of paper wasp and yellow jacket nests is that they are made out of plant fibers collected by chewing leaves with their mandibles (mouth parts) and carrying the fiber in their mouth and digestive tract. These plant fibers are laid down with a type of sticky adhesive in their saliva. This saliva is water-proof and makes the nests very strong and water repellent. Each nest starts with a petiole, or stalk, from which the hexagonal comb shaped cells are developed, much like bees. If you look closely at the cells, or for those that encase their nests with paper (aerial yellow jackets) at the outside of the nest, you'll notice beautiful layering of white, brown, and grey. These are simply layers of plant fibers that are being added by the worker wasps. You can often find wasp nests in the eves of houses, around window overhangs, or under bird boxes. Yellow jacket nests can be found above ground, hanging in trees (aerial yellow jackets), in wall or tree cavities (German yellow jackets), or below ground in excavated chambers. The underground chambers of yellow jacket nests are fascinating because they look exactly like the roundish aerial nests, complete with paper covering, only underground. Check out this PDF from Washington State University Extension for a nice cross sectional drawing of an underground nest. There's an old wives tale that suggests that the higher the yellow jacket nest is in the tree, the worse snow you'll get for winter. This has yet to be proven though!
Winter is a great time to check out the wasp's nests up close and personal, or to remove them. This is because all of the workers (females) and males die off with the first hard freeze. The fertilized queens are the only ones to survive by overwintering in cracks in trees and wood, in the external openings of houses, under leaf litter or bark. In the Spring the wasps will build a new nest starting with a nucleus of eggs and workers laid by the emerging queen. Most of the paper wasps do not re-use old nests. This may be because the paper does not over-winter well in the elements or to decrease parasite loads. You can safely remove wasp nests in the winter and during the coldest months. The paper can also be used for art or decoration (I made a particularly lovely Valentine one year with paper wasp paper). In the warmer months do not remove the nests yourself and certainly don't use gasoline!
Unfortunately for the paper wasps they are often confused with their more aggressive wasp cousins the yellow jackets. See the pictures below for a comparison.
Paper wasps are about the same size, if not a bit larger, than yellow jackets (.5" long), however paper wasps are not aggressive unless disturbed around their nests. Both can sting multiple times when provoked and the two species can look incredibly similar. Because of this similarity it's best to leave them all alone and give them a wide berth. Yellow jackets are the ones with a temper, especially the invasive German Yellow Jacket which is most prevalent in the US. I've been chased and stung more than once when weeding the garden on top of a hidden nest!
On the bright side, the two species are alike in that they feed mostly on nectar, fruit juices, and garden pests such as biting flies, harmful caterpillars, beetle grubs, and blow flies. They are known as extremely beneficial pollinators and biological pest control. Unlike paper wasps yellow jackets are also opportunistic and will feed on protein such as roadkill or fish when available during early Spring months. This acts as a supplement of protein for their young. Despite the potential for stings, if you can leave a nest in your garden or home without threat to people then their benefit may outweigh their threat, especially for gardeners.
If you need to control wasps, there is one tried and true method that I've found quite successful, and that works without chemicals or calling an exterminator. It's called the Waspinator or Beee Free wasp nest. It works on a very simple principle. Wasps have been proven to have facial recognition abilities that equals that of humans, they're very visual creatures. When they see another "wasp" nest in the area they will automatically assume it's another competitor and not build there. The Waspinator is especially effective on boats and in high areas. I've even seen crocheted ones offered on Etsy!
If you're out walking this winter, and you happen to see a paper wasp nest, take a moment to look more closely at the beautiful architecture and paper striations in the construction of the nest. It's quite a treat that you will not get come spring. However, remember that even though they can sting wasps are beneficial pollinators and helpful in controlling pests in our gardens and around our homes.