Field Guide to August 2022

Timber Rattlesnake Breeding

By Julia Pupko

A rapid staccato sound, like an egg shaker, rattles through the trees on a rocky hillside near West Haven, Vermont. That sound can only mean one thing in this state—a Timber Rattlesnake (Crotalus horridus). Once ranging from southern Vermont through the Champlain Valley, Timber Rattlesnakes were nearly eradicated—bountied and killed on sight, until 1971. Currently, the only known breeding populations exist in Rutland County, and the snake has been listed as Critically Imperiled in the state. Recovery for this species has been difficult because of their breeding habitats. They are a “K” selected species, so they live a long time (20-25 years), don’t produce too many young, and populations change slowly. Additionally, Timber Rattlesnakes take multiple years to reach sexual maturity and begin reproducing (around 5 to 7 years for males and 6 to 11 years for females).

August is the peak of these snakes’ breeding and birthing season. Once females have undergone their annual shed between June and July, they begin to release pheromones, attracting male rattlesnakes. However, fertilization does not occur immediately. Females store the sperm over winter and do not release it until May. After about 90 days, they give birth to live young. Babies are usually born from mid-August until the end of September. Females only reproduce every three to six years, so those who give birth do not mate again in the same season.

Timber Rattlesnakes are unique in the reptile world because mothers stay with and care for their young until they complete their first shed, which occurs around 10 days after birth. Young rattlesnakes can care for themselves immediately after birth and follow their mother’s pheromone scent back to their den when they venture out to hunt.

Soon after their breeding season ends, Timber Rattlesnakes begin migrating to their winter hibernaculum—cavities on southern-facing rocky slopes—where they overwinter in groups. Timber Rattlesnakes typically use the same hibernaculum each year for generations.

Although these snakes are venomous, Timber Rattlesnakes are not aggressive and do everything they can to avoid humans. Even when threatened to the point of biting, they usually employ “dry” bites, meaning they do not inject venom. Timber Rattlesnakes can choose whether or not to utilize venom when they bite and individually push out or retract their fangs. While it is unwise to attempt handling one of these snakes, they are not a “horrid” species to be feared, as their scientific name C. horridus, suggests.

Bee of the Month

By Spencer Hardy

August brings an explosion of goldenrods, asters, and sunflowers—each with a unique suite of specialist bees. However, one bee is about to emerge that will completely ignore all these tall and showy flowers. Instead, the Parnassia Miner (Andrena parnassiae) is singularly focused on a small, white flower growing in certain fens and a few rocky floodplains. Fen Grass of Parnassus (Parnassia glauca) is limited to alkaline soils and seems to do best with regular disturbances like flooding, grazing, and even mowing. It is threatened by development, invasive species, and nutrification. While its host plant is absent from large portions of the state, Vermont may be one of the major strongholds for this bee, a species that remained largely a mystery until the last decade. Recent work has shown serious threats to the flower, and we still have much to learn about the distribution, natural history, and conservation of what may someday become an iconic Vermont species. Read more about both the flower and the bee on Bryan Pfeiffer’s blog.

A Chipmunk Story

By Julia Pupko

A slight rustle at ground level echoed to my left, indicating that I was not alone on the wooded trail I was exploring. I froze, hoping that the rustler would make themselves known. I was not disappointed—mere moments later, a small rusty-brown form, complete with black and white stripes, emerged from the underbrush. Pausing in the middle of the trail, the Eastern Chipmunk (Tamias striatus) began to snack, dropping some of their cheek-fillers in the process. After a few minutes, the chipmunk departed, leaving some unfinished food on the trail. Upon inspection, I recognized False Solomon’s-seal (genus Maianthemum) berries.

Eastern Chipmunks breed twice a year in Vermont, once in early spring and once in July. Young are born after a 31-day gestation period, making August the second month for baby chipmunks. They are born blind, naked, and helpless in their underground den (or burrow). A burrow is less than a meter from the soil surface and can have up to 10 meters of interconnected galleries. Dens have two primary chambers: one containing a nest made of crushed leaves and the other storing food. Chipmunk young mature rapidly, gaining their stripes at eight days of age, opening their eyes at one month, and leaving the den at around six weeks of age. After two months, the young are fully independent and disperse, with males dispersing farther than females.

Because Eastern Chipmunks store food in large caches up to a meter underground, many seeds don’t disperse. Some chipmunks occasionally cache seeds and berries outside their den, which can lead to the successful establishment of seedlings. However, Eastern Chipmunks do play a crucial role as spore dispersers for Truffle mushrooms. Truffles are mycorrhizal fungi—they form symbiotic relationships with trees, expanding their root network, capturing nutrients, and creating communication systems between different trees in exchange for photosynthetic sugars from the tree. Truffles fruit underground and therefore cannot rely on the wind to disperse their spores, as many mushrooms do. When a chipmunk digs up a truffle, it spreads the spores as it carries the mushroom away and eats it. The truffles emit a strong odor that chipmunks and other animals can detect, signaling that they are ready to be dug up and consumed. To learn more about this fascinating ecological web dependent on truffle mushrooms, check out this Northern Woodlands article.

Ruby-throated Hummingbird Migration

Julia Pupko

As I sit quietly in a folding chair, reading a book, I hear a loud buzz rapidly increasing in volume as its source zips towards me. I look up, ducking slightly in anticipation—a massive Carpenter Bee keeps getting confused by my floral shampoo and brightly-colored shirt. I assume she has not quite given up her pollination attempts yet. However, I quickly realized it was not a bee but a Ruby-throated Hummingbird (Archilochus colubris).

The Ruby-throated Hummingbird is Vermont’s only breeding hummingbird species. Weighing a mere 2.8 to 4 grams, they can beat their wings around 50 times per second and manage to migrate from North America to Central America and the Caribbean twice a year for their whole life. By early August, some male Ruby-throated Hummingbirds have already begun their fall migration. Females soon follow, and migration peaks in September. By October, the final birds have reached the Gulf coastline of the southeastern United States and are preparing to make the last leg of their journey. They will either follow the coastline and enter Mexico by land or fly straight over the Gulf of Mexico. During the fall, most follow the land to avoid hurricanes and other storms over the Gulf. Ruby-throated Hummingbirds fly low over the treetops during the day, so they can easily stop to fuel up on nectar and insects as they travel. They usually feed in the morning, travel midday, and forage again in the late afternoon before hunkering down for the night.

Be sure to upload observations of Ruby-throated Hummingbirds to Vermont eBird!

Turtle Time!

By Julia Pupko

The sediment along rivers, lakes, and streams tells many stories. It captures the comings and goings of mammals, reptiles, birds, amphibians, invertebrates, people, and others as they flow to and from the river. Then a storm comes, erasing the storyboard surface and paving the sediment for a new novel to be recorded. In August, you may find turtle tales scrawled along the sides of Vermont’s water bodies.

In Lake Champlain and its tributaries, August is an exciting time for Eastern Spiny Softshell Turtles (Apalone spinifera)—their eggs begin to hatch. Spiny Softshells become sexually mature at about 12 years of age and typically mate in May. They lay their eggs in sandy or gravelly substrate in June, which hatch 82 to 84 days later. Hatchlings emerge between late August and October and must swiftly find a suitable underwater resting place for their winter hibernation. Spiny Softshells can live over 50 years, and females can reach 21 inches long. These turtles can also weigh up to 25 pounds—hefty considering their shells are ultralight and thin.

Like Spiny Softshells, Snapping Turtle (Chelydra serpentina) young also begin to hatch in August. Their nesting season lasts from April through November, but most egg clutches in New England are laid between May and June. Snapping Turtles have temperature-dependent sex determination, meaning the temperature of incubation determines whether the offspring are male or female. Eggs incubated at 68 degrees Fahrenheit yield females, those incubated between 70 and 72 degrees Fahrenheit yield both sexes, and those incubated at 73 – 75 degrees Fahrenheit produce only males.

Other turtle species, such as the Northern Map Turtle (Graptemys geographica), and the Eastern Box Turtle (Terrapene carolina), begin to hatch at the end of August but usually don’t emerge from eggs until September.

Many turtle species, including the four described here, experience high nest mortality from predation or human disturbance. If you see a turtle nesting, please give the area a wide berth and do your best to keep others away from the site! Be careful who you share details of the nest with—several native species, including Map Turtles, Box Turtles, and Wood Turtles, risk being poached. They are often sold in the exotic pet trade, a practice that can quickly decimate wild populations. Sharing nesting information about turtles on social media can often lead to the nest being poached, so be cautious!

However, please share your turtle sightings to the Vermont Atlas of Life on iNaturalist—even the vulnerable species! iNaturalist has special protections to ensure that a species’ whereabouts remain obscured if it’s at risk. By submitting your observations of Vermont’s turtles, you can help biologists better understand how their populations are fairing.

Flowers of the Month

By Julia Pupko

Keep your eyes out for these flowers this month as you explore Vermont’s meadows and forests!

Black-eyed Coneflower (Rudbeckia hirta)
Commonly called Black-eyed Susan, this striking plant has yellow petals, a black center, and simple, alternate leaves. You can typically find Black-eyed Susans in fields, disturbed habitats, and woodland edges. According to GoBotany, two varieties of this plant inhabit New England. One (Rudbeckia hirta var. hirta) is a rare native flower found in Massachusetts and Vermont. The other (R. hirta var. pulcherrima) is introduced and found throughout New England.

Rattlesnake Plantain (Goodyera pubescens)
This evergreen plant is not a plantain but an orchid species. Found in the moist upland soils of coniferous and deciduous forests, this plant has dark green, pubescent leaves with white veins. The leaves grow in a basal rosette, meaning they only grow at the base of the plant from the central stem and surround the center point to form an overlapping circle of leaves. Their flowers are small and white, clustered around the top portion of the stem.