As leaves continue to fall and the first flakes begin to fly, the oncoming cold weather seems to bring nature to a standstill. On the contrary, there remains a lot to be discovered in Vermont during this transitional period. Careful observers can witness the tail end of migration as waterfowl and hawks continue their journey south, a few hardy species of butterflies and moths remain to further brighten sunny days, and avian visitors from even further north will begin to raid feeders across New England. Learn more in our Field Guide to November.
By Emily Anderson
At this time of year, animals such as weasels and snowshoe hares are trading in their summer brown and red hues for winter white. These pearly coats are thicker than their summer fur, helping them stay warm throughout the long, cold months. They also come with the added advantage of helping these critters blend in, camouflaging them from predators and prey alike. In Vermont, this transformation usually begins in late October and early November.
Although these animals are well-adapted to living in colder regions, they are struggling to adjust to the unique conditions climate change creates. Anyone who has lived in Vermont for more than a couple of years knows that winter is becoming a bizarre, unpredictable season here. Snowfall patterns are erratic, often happening much later than they did several decades ago. Snow cover is also quite fickle, frequently leading to brown bare stretches in previously powder-covered months.
The casual observer may not understand why these changes can prove so tricky for our frosty-coated friends. The secret lies in the conditions that trigger the change in their pelts. Contrary to what some may believe, it is actually the changing day length, not the drop in temperatures, which initiates the color shift. The waning hours of daylight trigger a response in the hypothalamus, commonly referred to as the “master gland”, and cause animals to undergo many changes that help them survive the winter, including changes in coat color and thickness. For a very long time, climate patterns up north were stable enough that these changes in day length served as an appropriate signal. However, the altered temperature and snowfall patterns related to climate change mean that these animals are now preparing for weather that may arrive much later, if it arrives at all.
Once the perfect shade for disappearing into the landscape, the weasels’ and hares’ white coats are a stark contrast to the dreary greys and browns that now dominate early winter in Vermont. This makes them vulnerable to predation and could overtime cause their populations to decline if recent trends hold. It could also favor the survival of individuals whose fur remains brown all winter, as is occasionally documented in long-tailed weasels. Through the Vermont Atlas of Life project on iNaturalist, you can help us monitor these changes by recording any sightings of weasels, snowshoe hares, and other animals who are becoming ill-suited to their environment due to climate change.
By Kent McFarland
No, not the turkey on your platter. We’re talking about Northern Shrikes, aka “butcher bird” – a predatory songbird that breeds in the far north and winters in southern Canada and the northern United States. Shrikes feed on small birds, mammals, and insects, and are known for impaling them on spines trees or barbed wire fences. Chris Rimmer and Chip Darmstadt discovered that they can return winter after winter to the same territory. Using band recoveries, they found 12 cases in which shrikes were recaptured at or near the same winter location one to three years later. You can see if there are any reported near you on Vermont eBird. Keep a lookout for these feisty songbirds and be sure to report your sightings to Vermont eBird, a project of the Vermont Atlas of Life.
By Nathaniel Sharp
The Shaggy Mane is no doubt an odd, yet accurate name for one of Vermont’s most well-known species of fungus. Also going by the names of ‘Ink Cap’ and ‘Lawyer’s Wig’, this mushroom tends to spring up after rainy autumn days singly or in clumps. Easily identified by their shaggy appearance, created by the peeling scales present on the oblong cap, this fungus undergoes a startling transition in late-fall in an effort to distribute its spores.
The tall, oblong shape of the Shaggy Mane gives it an advantage over other mushrooms, as it has much more room in its gills to store the spores that will go on to become new fungal bodies. The conundrum this fungi faces is how to distribute its spores when they are all hidden deep within the cap. Deliquescence is the answer. As the fungus matures, the cap slowly deliquesces, or appears to melt away. This is an ingenious method for spore distribution, as while the cap slowly liquefies from bottom-to-top into an inky sludge, the spores that were hidden deep within the cap are exposed to the wind and free to blow on to their next destination.
Before it has melted into an ink-covered stem, a Shaggy Mane might eat a couple of nematodes along the way. Nematodes are small subterranean worms, some of which can cause serious damage to plants. Occasionally they may come into contact with the Shaggy Mane’s mycelium, a filamentous appendage of fungi that spreads throughout their substrate, which devours the unlucky worm in mere hours. Microscopic ‘spiky balls’ produced by the Shaggy Mane’s mycelium pierce the membrane of the nematode, turning it inside out and pumping it full of paralyzing toxins, before it is digested and assimilated into the fungus.
Next time you come across one of these common fungi, remember to snap a photo and post it to the Vermont Atlas of Life on iNaturalist, and take a second to wonder about the microscopic battle going on beneath this fascinating fungus.
By Emily Anderson
This is a good mast year. It’s one of those phrases that many people hear, but may not know exactly what it means. This phrase commonly passed between Vermonters who live close to the land or spend a lot of time out in the woods, refers to the large crop of seeds or fruit produced by a particular tree population that year. There are two types of mast: hard mast and soft mast. Hard mast consists primarily of seeds and comes from trees such as oaks, beeches, and hickories. Soft mast refers to fruits and catkins, and comes from trees and shrubs such as apple, mountain ash, and birch. Not every year is a good mast year, though. Many tree populations can go two or more years with minimal seed production before their next bumper crop. Scientists are still unraveling the complex mechanisms driving seed masting in the hopes of better understanding how climate change may affect seed crop production in the future.
What scientists do know is that seed crop production is closely linked with certain animal populations that rely on these energy-dense food sources. Many seed predator populations rise and fall in relation to fluctuations in seed production. One species that has received special attention in recent years is the white-footed mouse, due to its status as a known reservoir for Lyme disease. Research from the Cary Institute of Ecosystem Studies shows that white-footed mice populations explode directly following good mast years. These higher mouse populations create more opportunities for ticks to feed successfully and get infected with Lyme and other tick-borne illnesses. Based on their studies, if this year is indeed a good mast year, then we will likely see an increase in Lyme disease infections in 2021.
While this may seem like an excellent reason to dread good mast years, their increased food production does benefit many other animals, including humans. Many people forage for acorns and process them into products such as flour. And of course, it wouldn’t be fall in Vermont without apple picking. Areas with clusters of these mast producing plants also make great places to see all sorts of wildlife feeding. So grab your camera or set up your trail cam and see what comes to visit your nearest fruiting or seeding tree!
By Kent McFarland
Black Bear aren’t true hibernators. Sure, their respiration and metabolic rate decrease during winter sleep, but their body temperature remains close to normal. A bear in a winter den can be easily aroused within moments, but an animal that is a true hibernator may take several hours to come to its senses.
For animals that are true hibernators – body temperature, respiration, and metabolic rates are all considerably decreased. Take the Woodchuck as an example. Their heart rate goes from 80 beats a minute when active to just 4 or 5 beats a minute when in hibernation. Their body temperature drops from 98 degrees to a mere 38 degrees Fahrenheit. A Woodchuck’s incisors grow continuously and are kept short through their constant gnawing. But during the winter hibernation, growth stops. True hibernators do wake up every few weeks to nibble on food, and in the case of the Woodchuck, use the underground outhouse.
Food supplies are the most critical factor determining when Black Bears den each the fall. When food is abundant, they’ll continue eating throughout the snows of November and into December. When autumn foods are scarce, most bears den by mid-November.
The den is commonly a brush pile. It may also be a pocket or cave in rocky ledges; a hollow in a large tree or a fallen log; a sheltered depression or cavity dug out at the base of a log, tree, or upturned root; or even a simple hole dug into a hillside. Male bears den up almost anywhere. Females, however, are more particular, selecting protected sites and lining them with stripped bark, leaves, grasses, ferns, or moss.
Listen to an episode of Outdoor Radio from last winter when we visited a den of a radio collared Black Bear to check on its health.
By Kent McFarland
On even the darkest, coldest days of November, there are still signs of lepidopteran life if one looks close enough. Two moth species of the genus Operophtera, known as the Bruce Spanworm Moth (O. bruceata) and the introduced Winter Moth (O. brumata) manage to survive in conditions that would kill most other moths and butterflies. Dressed in shades of light brown and as small as a penny, these moths are easy to overlook, but what they lack in visual appeal they make up for in their fascinating morphology.
Incredibly, these moths can fly with air and body temperatures ranging from just 27 degrees Fahrenheit up to a balmy 77 degrees Fahrenheit. Generating enough warmth to power their flight muscles and get off the ground is a tall order. How do these tiny moths fly in cold conditions that make flight muscles sluggish? Morphology appears to be the key.
The male Bruce Spanworm Moth has one of the lowest wing-loads (total weight divided by wing area) of any moth measured. This both reduces the number of wing beats and lowers the energetic cost required to sustain flight. These little moths also have one of the highest flight muscle to body size ratios. These surprisingly bulky muscles are able to compensate for the reduced muscle contraction associated with cold temperatures and continue to generate enough tension to power each wingbeat. Powerful muscles, combined with efficient wings allow these moths to operate in very low temperatures as they seek the scent of females wafting pheromones.
The female Bruce Spanworm Moth has also adapted to survive in low autumn temperatures, but in a completely different way. They are flightless. The female Bruce Spanworm Moth has no wings at all while the female Winter Moth retains vestigial, yet nonfunctional, wings on her back. When the females emerge in October and November, they laboriously crawl up the lower trunk of a host tree, where they solicit flying males with a chemical cocktail.
A flightless lifestyle holds several advantages for female Bruce Spanworm Moths. Without bulky flight muscles weighing them down, females are able to dedicate over 60% of their total body weight to egg production, holding an average of 143 eggs. A flight model by James Marden, a biologist at Penn State University, suggested that if a female were to retain enough flight muscle to sustain weak flight at optimal temperatures, she would experience a 17% reduction in egg-carrying capacity. In order to sustain powerful flight, an 82% reduction would need to occur in order to make room for the powerful flight muscles required.
Flying and crawling along through the woods during some of the coldest months of fall surely must have some advantage for these moths, right? It is likely that these adaptations occurred in response to a powerful natural selection force, predation. By late October and November, most of the insectivorous birds have migrated south and bats have migrated or gone into hibernation for the winter. With most significant moth predators out of the picture, these moths have free-reign of Vermont’s forests. If you happen to spot one of these fascinating moths, snap a photo and submit your sightings to the Vermont Atlas of Life on iNaturalist.