Because yellowjackets do not produce or store honey one might wonder why striped skunks, raccoons and black bears frequently dig up their underground nests. It is the young yellowjackets (larvae), not honey, that is so highly prized by these insect-eating predators. At this time of year it is crucial for them, especially black bears who go for months without eating or drinking during hibernation, to consume enough protein to survive the winter.
Whereas adult yellowjackets consume sugary sources of food such as fruit and nectar, larvae feed on insects, meat and fish masticated by the adult workers that feed them. This makes the larvae a highly desirable, protein-rich source of food. (Yellowjacket larvae reciprocate the favor of being fed by secreting a sugary material that the adults eat.)
Three to five thousand adult yellowjackets can inhabit a nest, along with ten to fifteen thousand larvae. Predators take advantage of this by raiding the nests before frost kills both the adults (except for fertilized young queens) and larvae in the fall. Yellowjackets are most active during the day and return to their underground nest at night. Thus, animals that raid them at night, such as raccoons, striped skunks and black bears, are usually very successful in obtaining a large meal. Occasionally, as in this photo, the yellowjackets manage to drive off predators with their stings, leaving their nest intact, but more often than not the nest is destroyed and the inhabitants eaten. (Thanks to Jody Crosby for photo op of yellowjacket nest (circled in red) dug up by a black bear – note size of rock unearthed.)
When your quest is to find out as much as you can about the identity, activity, diet and territory of your four-footed neighbors, it is logical to make the most of all your senses. Tracks can be seen, scrapings and bite marks on a tree can be felt and yes, one’s sense of smell can enhance any tracking expedition. Just as the tracks and scat of different species of animals have distinctive characteristics, so does the urine of different animals. Scent marking, including urination, is a behaviour used by animals to identify their territory, and therefore a highly visible sign in winter.
At this time of year, foxes are breeding, and without even putting your nose near where a fox has marked his territory with urine, you can detect its skunk-like odor as you pass by. If you’re so inclined (and I realize many readers may not be) you can heighten your sensory experience as well as your identification prowess by sampling the smell of other animals’ liquid waste. White-tailed deer urine has a pungent, piney smell, quite pleasing to this naturalist’s olfactory receptors. You can detect a porcupine den from a considerable distance by the pungent, very distinctive but hard to describe odor of its urine (which spills out onto and coats the bark of a tree den, thereby advertising the porcupine’s presence). Coyote urine smells very much like a domestic dog’s, and members of the weasel family often have musky-smelling urine, though a recently-sniffed fisher marking had very little scent.
Needless to say, it’s a lot easier to discover and sample urine when there’s snow on the ground and it is more evident. Virginia opossums, snowshoe hares, red and gray squirrels, eastern coyotes, red and gray foxes, raccoons, fishers, mink and striped skunks are all in or entering their breeding seasons, when scent marking is more frequent. Snow is currently on the ground, at least in northern New England. It’s prime time for olfactory activity, if you’re game. (Photo: stump marked by a red fox)
Winter’s coming and in the Northeast, Striped Skunks are preparing for the cold months ahead. Before they usurp the abandoned quarters of a Muskrat or Red or Gray Fox (or bunk with a willing Opossum or Raccoon), they spend a great deal of time foraging and putting on life-sustaining fat. Even though a state of torpor slows their metabolism down during the coldest months, skunks must bulk up in the fall, as they lose up to 65 percent of their body weight over the winter. Thus, they meander far and wide looking for food this time of year. In addition, this year’s young are still dispersing. For these reasons, you may have encountered the smell of skunk or the sad sight of striped roadkills in your travels lately.
When under dire stress, adult Striped Skunks will employ their two anal glands and anoint a perceived threat up to 16 feet away (with the wind’s help) with their potent musky spray of butyl mercaptan. (This same compound is used as an additive to natural gas (which is almost odorless) to enable its detection by smell when natural gas escapes or leaks from pipes.)
Often it is assumed that very young skunks do not have this capability, and for the first seven days of their life, they don’t. However, musk is present in a skunk’s anal glands at birth and can be emitted on day 8. The pictured skunk (and its three siblings) were rescued after their mother was killed by a car, and as you can see, thanks to a positive experience with the nurturing hands of its rescuer (Lou White), it is not interested in utilizing its defense mechanism to defend itself against an admiring naturalist. (Photo by Lou White)
Naturally Curious represents a passion for learning and teaching about natural history that I am fortunate enough to be able to pursue. If and when the spirit moves you to support my tiny contribution to your day, I would love for you to donate to a fund that was set up to support my recently-widowed daughter and her two-year-old. If you choose to contribute, you may go to https://www.plumfund.com/financial-hardship/sadie-brown-otis-brown-fund. Thank you so much.
Female Snapping Turtles spend a lot of time and effort finding suitable sandy soil in which to dig their nest and lay their eggs. Some turtles have been found laying their eggs as far as a mile from the nearest water source. Once she has laid her eggs and covered them with soil, the female snapper returns to her pond, leaving her eggs to hatch on their own, and the hatchlings to fend for themselves.
It is estimated that as many as 80 to 90 percent of all turtle nests are destroyed by predators, weather conditions and accidental disturbances. Most of the damage is done by predators – skunks, raccoons, foxes, crows, among others. Most nests are discovered by smell, and most are raided at night. The fluid that coats the eggs, that is lost by the mother during egg laying or is lost through breaks in the eggs, produces a smell that is easily detected by predators. While a majority of nest raids happen within the first 48 hours of the eggs being laid, studies have shown that predation occurs over the entire incubation period (June – September). The pictured Snapping Turtle nest was dug up and the eggs consumed 10 days after they were laid.
If you are aware of a spot where a turtle dug a nest and laid eggs, you can try to protect the nest from predators by placing either a bottomless wire cage or an oven rack over the nest site, and putting a heavy rock on top. The tiny hatchlings will be able to escape through the openings but hopefully, if the rock is heavy enough, raccoons and skunks will become discouraged and give up trying to reach the nest.
The next Naturally Curious post will be on 7/5/17.
Striped Skunks are on the prowl, as your nose may have told you recently – males are eagerly seeking out the company of females at this time of year and are often hit by cars traveling at night. The peak of the Striped Skunk breeding season — the third week of March — will soon be upon us. Males will mate with several females in succession and then they often protect their harem against other males by hitting them (other males) with their shoulders or biting their legs. Once a female has been successfully bred, she will not allow further mating activity and will viciously fight any male that attempts it.
Striped Skunks do have predators other than Great Horned Owls (bobcats, foxes and coyotes-fishers have been known to prey on skunks, but very infrequently), but these predators have to be pretty desperate before they will prey on a skunk. Automobiles and disease kill more skunks than all of their predators put together, but Great Horned Owls have the distinction of being the primary predator of Striped Skunks.
Being a nocturnal hunter, a Great Horned Owl necessarily consumes prey which are nocturnal. Striped Skunks are active at night and are consumed by Great Horned Owls with regularity, even though a skunk can weigh up to three times as much as a Great Horned Owl (average GHO weighs a little over 3 pounds) and has a potent way of defending itself.
For many years scientists assumed that birds had a poor sense of smell because the area of a bird’s brain involved in smell is relatively small compared with the area found in mammals. However, recent research reveals that birds have a high number of active genes that are associated with smell, and many species may have an excellent sense of smell. It’s fairly safe to assume, however, from its consumption of skunks, that the Great Horned Owl’s sense of smell is not very well developed. In addition, if a skunk sprays, much of the odor is absorbed by the Great Horned Owl’s leg feathers, which extend down to its talons.
A favorite memory of mine is walking through a field at dusk and suddenly noticing a strong skunk-like smell coming from above, not below, me. A Great Horned Owl silently flew overhead, with only the tell-tale smell of a recently-captured skunk announcing its presence.