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Vermont hillsides in summer © Kent McFarland

Field Guide to June 2024

Here in Vermont, we dream of June during the darkest days of January. Verdant wooded hillsides glowing brightly under a robin egg sky. Warm afternoon breezes roll through the valleys as we lounge by the clear waters of a cold river. Choruses of birds wake us each morning. The smell of freshly cut grass wafts through the window. Enjoy this guide to some of the month's delights as the dream of June comes true.

By Vermont Center for Ecostudies June 13, 2024
Eastern Whip-Poor-Will © Kent McFarland
Eastern Whip-Poor-Will © Kent McFarland


By Kent McFarland

During spring and summer nights, the relentless chanting of whip-poor-will, whip-poor-will, was once heard throughout the Northeast; however, many of the Eastern Whip-poor-will’s former haunts have grown quiet, as abandoned farmland reverts to forest and development encroaches on dry woods with open understories.

The Eastern Whip-poor-will is a nocturnal, aerial insectivore found in the eastern United States and into Canada. Though whip-poor-wills are most commonly heard calling at dawn and dusk, they will forage and call on calm, clear nights when the moon is at least half full. Becoming active roughly half an hour after sunset, these birds fly silently out of forests with little or no underbrush into open areas, such as pastures, in search of insects. More than half of their diet consists of moths, though they are also known to eat beetles, ants, and wasps.

During the day, whip-poor-wills roost on the ground or on low-lying branches. Whip-poor-wills do not build nests. The female lays two eggs on the forest floor, usually in a shady, well-drained patch of ground amidst leaf litter. The eggs, chicks, and adults are well camouflaged, affording them some protection from predation.

Whip-poor-wills breed from Saskatchewan to the Maritimes, down the eastern seaboard to northern Georgia, then west to Kansas and into Minnesota. They are considered medium-distance migrants and arrive on their breeding grounds in March, then leave in September to overwinter in the southeastern U.S. and Central America.

The species was listed as Threatened in Vermont in 2011, following decades of population decline possibly stemming from forest maturation, development, loss of suitable edge habitat, and predation from cats, raccoons, and other predators associated with human settlement. Declines in large moth populations from pesticides and introduced parasitoids may also be a factor.

To better understand whip-poor-will habitat characteristics, identify important breeding locations, and obtain a more precise population estimate for Vermont, VCE is conducting surveys throughout the state. Learn more about how to participate in this project as a community scientist.

Canadian Tiger Swallowtail <i>(Papilio canadensis)</i> in Vermont. © Kent McFarland
Canadian Tiger Swallowtail (Papilio canadensis) in Vermont. © Kent McFarland

Flying Tigers are Confusing

By Kent McFarland

And you thought you had trouble telling one butterfly species from another. Tiger swallowtails, which are rather large, yellow butterflies with black tiger stripes, flutter over the hills and valleys of eastern North America each spring and early summer, sometimes in great numbers. But figuring out which tiger is which has baffled lepidopterists for more than three centuries.

The first New World butterfly to be painted by a European artist was a tiger swallowtail. John White painted one on Roanoke Island, North Carolina, in 1587 while serving as the expedition leader of Sir Walter Raleigh’s third trip to America. Despite exaggerating the wing shape, his details were relatively accurate.

Linnaeus, the father of modern taxonomic naming, classified tiger swallowtails as a single species in 1758 (Papilio glaucus). But Linnaeus had actually named the species from a black-colored female—a rarer version of the group that looks just like the more common yellow females, except for a darkly pigmented wing background. These dark females generally occur from Massachusetts to Florida, the southern portion of the tigers’ domain.

Eastern Tiger Swallowtail <i>(Papilio glaucus)</i> dark form female nectaring on Buttonbush in Maryland. © Kent McFarland
Eastern Tiger Swallowtail (Papilio glaucus) dark form female nectaring on Buttonbush in Maryland. © Kent McFarland

Why are there dark-colored females? They are thought to have evolved to mimic the dark color of the foul-tasting and poisonous Pipevine Swallowtail butterfly. When an otherwise palatable species evolves to closely resemble an unpalatable cousin, this phenomenon is called Batesian mimicry.

Linnaeus also observed the more common, yellow-colored female tiger swallowtail but decided it was another species altogether. Making matters even more confusing, a contemporary of Linnaeus documented a male tiger swallowtail, which is also yellow, but decided it, too, was its own species.
In the 1800s, biologists realized that the three species were only differentiated by color and lumped them together under the common name, Eastern Tiger Swallowtail. Starting in at least 1906, however, lepidopterists noticed that the more northern populations were smaller and had slightly different markings. Some began recognizing this as a subspecies of the Eastern Tiger Swallowtail and called it canadensis.

In 1991, biologists from Michigan State University announced that they had enough evidence to declare canadensis as a species of its own: the Canadian Tiger Swallowtail. Their evidence included genetic differences, color and size differences, caterpillar food-plant use, lack of black-colored females in canadensis, and only a very narrow hybrid zone between the two species. It is now widely accepted that Eastern Tiger Swallowtails are found southward and Canadian Tiger Swallowtails are found northward.

The range of the Eastern Tiger Swallowtail just barely makes it north into Vermont and New Hampshire. Most of the tiger swallowtails we see around here, therefore, are Canadian Tiger Swallowtails.

Generally, Canadian Tiger Swallowtails are flying around from the beginning of May until the end of June (later in higher elevations), while Eastern Tigers fly from June into October. So if you see a tiger swallowtail sailing over a meadow from mid to late summer, it just might be an Eastern. But even up close, they look very similar. The Eastern is larger, with the underside marginal forewing band broken into yellow dots separated by black borders. On the underside of the Canadian Tiger’s hind wing, the black line nearest the body is very wide. Minute details for sure. Even worse is that, in the hybrid zone between species, there are many that appear intermediate. In Vermont and New Hampshire, we are in the thick of the intermediate zone.

But the story doesn’t end there. In 2002, another potential tiger was described by two lepidopterists, Harry Pavulaan and David Wright. “When it became apparent that there were inconsistencies in the natural history of mountain populations versus lowland populations of tiger swallowtails, an intensive effort was made to study the field biology of the mountain populations,” said Pavulaan. They have named the new species the Appalachian Tiger Swallowtail and affectionately refer to it as “Appy.” So far, it is known only from the central and southern Appalachian Mountains. Finally, a fourth tiger swallowtail species—the aptly named Western Tiger Swallowtail—resides in western North America.

Appalachian Tiger Swallowtail <i>(Papilio appalachiensis)</i> at the Great Smokey Mountain NP -Oconalluftee Visitors Center. © Kent McFarland
Appalachian Tiger Swallowtail (Papilio appalachiensis) at the Great Smokey Mountain NP -Oconalluftee Visitors Center. © Kent McFarland

Why have tiger swallowtail identities been so hard to pin down? Probably because tiger swallowtails are comprised of sibling species—two or more populations that have become reproductively isolated from one another, yet so similar in outward appearance as to be lumped together even by experts. Careful, intense study of details such as anatomy, biochemistry, and behavior can bring sibling species to light. But there can be many dead ends and evolutionary tricks that confuse biologists.

If you want to wade into the world of tiger identification, now is the time! The lovely Canadian Tiger Swallowtails are flitting over meadows near you. Learn more about the details of tiger swallowtail identification in this blog post from Bryan Pfeiffer. And be sure to add your observations to


Common Loon <i>(Gavia immer)</i> © Susan Elliott licensed under CC-BY-NC
Common Loon (Gavia immer) © Susan Elliott licensed under CC-BY-NC

Loon Language

By Kent McFarland

For many northeastern lakeshore residents, Common Loons’ calls hold a special place in the summer soundscape. Their haunting cries—heard most frequently from mid-May through June—are perhaps one of the most fascinating things about loons. They use four distinct calls to communicate with their families and other loons.

The Mournful “Wail” – An “ooohh ahhhh” is often the sound of loons identifying or calling to each other. It can also signal initial signs of a mild disturbance.


The Laughing “Tremolo” – A trill or series of trills can be a sign of distress, alarm, or, occasionally, excitement.


The Crazy and Wild “Yodel” – This is the male territorial call, usually directed at unwelcome loons. Every male has a distinct yodel and uses it to transmit a lot of information, from how big the male is to his level of motivation to defend.


Hoots and Coos – On a quiet evening you can hear the loon family or group of loons in a “social gathering” communicating with each other.


Keep your ears perked for loons on bodies of water near you this summer, and be sure to report your sightings to Vermont eBird.

Wood Turtle <i>(Glyptemys insculpta)</i> © mellohrer (from iNaturalist) licensed under CC-BY-NC
Wood Turtle (Glyptemys insculpta) © mellohrer (from iNaturalist) licensed under CC-BY-NC

A Slow and Stealthy Traveler

By Emily Anderson

When June’s heat starts to take hold, who doesn’t want to take life a little slower? When it comes to masters of slowing down, look no further than the humble turtle. Vermont is home to seven turtle species, including the secretive Wood Turtle. From June to September, Wood Turtles split their time between the streams where they overwinter and seek refuge and their upland foraging grounds. Wood Turtles are omnivores whose diet reflects their mixed habitat; they regularly consume fish, invertebrates, insect larvae, earthworms, and plants. By mid-June, females seek out nesting areas, at times traveling up to one mile to get there. They prefer to dig their nests in soft soils and often create several false ones before deciding where to lay their eggs.

Wood Turtles are important members of stream communities and can serve as indicators of stream health. To survive, they need clean water, relatively undeveloped upland habitat, and intact connections between their streams and foraging grounds. Many other Vermont animals, from trout to mink, require similar conditions and benefit from measures that protect Wood Turtle habitat.

“Where are all of Vermont’s Wood Turtles?” you may ask. They are naturally elusive—even people who frequently visit Vermont’s streams may never encounter one. You may not even guess that they are found in all 14 counties! Unlike other turtles, which often bask on exposed rocks and logs, they prefer filtered light and vegetation to screen them from view.

There is another important reason why they are difficult to find: they are rare. In fact, Wood Turtles are listed as a Species of Greatest Conservation Need in Vermont. Over the years, their slow speed and undeniable charm have made them victims of both human-driven land use change and collection. Their frequent journeys across the landscape also make them common casualties along roadways, where our desire for fast travel conflicts with their slow pace. In many cases, mortality from these sources far outpaces this long-lived species’ reproduction rate, making it difficult for populations to recover.

If you are interested in learning more about how you can help Wood Turtles, visit the Vermont Fish and Wildlife website. If you want to learn more about Wood Turtles, listen to this episode of Outdoor Radio or read this article from the Orianne Society. And remember to share sightings with the Vermont Atlas of Life on iNaturalist—all locations are automatically obscured, so rest assured that you can safely share your discoveries and contribute to Wood Turtle monitoring in Vermont.


The Hidden Life of Jack

By Kent McFarland

The green and purple spadix that holds the preacher in Jack-in-the-Pulpit (Arisaema triphyllum) is neither bright nor showy and is often hidden under a sheathing bract that resembles broad leaves (the spathe, in botanical parlance). Typical of the Arum family, the spadix is covered with tiny flowers hidden deep in the spathe. With a strange-looking flower like this, who is the pollinator that dives deep within?

Tiny flies, called fungus gnats, are attracted to the smell and heat of a male Jack-in-the-Pulpit flower. The flies drop down into the spathe only to become trapped. Pollen clings to them as they search for an escape route. Finally, they escape through a small space in the bottom of the spathe and fly away. Their next stop might be another nearby Jack-in-the-Pulpit, but this time, they enter a female flower. There is no escape hatch at the bottom of the spathe. The flies bounce about trying in vain to escape and in the process, they drop pollen onto the pistol of an inflorescence.

Jack-in-the-Pulpit grows very slowly in the shaded forest understory. It may take a plant a couple of years to garner enough energy to produce a male flower. After a few years as a male, they may have enough energy stored in the corm, an underground stem where the plant stores starch, to grow a female flower and set seed. Depending on soil and light conditions, it may take a seedling up to three years to form a flower. After a few more years, it may grow a flower with both male and female inflorescence. The male flowers mature and pass before the female flowers to avoid self-pollination. If the growing conditions have been good, when it is about 20 years old, it may finally produce female flowers. But if at any time conditions become poor, it may revert back to less energy-costly male flowers again. Some of these plants can live to be 100 years old.

Caution, this plant is poisonous. The entire plant contains calcium oxalate, the stuff you find in many meat tenderizers. These needle-shaped crystals are found in specialized cells throughout the plant and can even bother some people who simply touch a broken part of the plant. Calcium oxalate causes an intense burning sensation if ingested. It literally tenderizes your mouth. Also called Indian Turnip, Native Americans dried the corms to make them safe for eating. But there is something in the woods that eats it raw without apparent harm.

I was passing through a large wet area in a rich hardwood forest several years ago when I came across a place that was pocked with diggings in the mucky soil. It didn’t take me long to realize that each pit had bits of Jack-in-the-Pulpit left scattered about. Black bears love to eat Jack-in-the-Pulpit, and they had recently paid this patch a visit. What would turn our tongues raw doesn’t seem to bother the bears at all.

Comments (1)

  1. X22Epice says:

    Hey people!!!!!
    Good mood and good luck to everyone!!!!!

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