“Sweet Nectar” Delivers
Kevin “Sweet Nectar” Hemeon strikes again. This intrepid naturalist has chalked up yet another Vermont state record. Even though he lives in Hoosick, NY (not far from Bennington County), Kevin is a legend of sorts among Vermont lepidopterists. The guy is a state-record machine. During the Vermont Butterfly Survey, Kevin racked up at least a half dozen state records. He was the first to locate in Vermont, for example, Pipevine Swallowtail, Common Buckeye and Common Checkered Skipper. A few years ago Kevin turned his exuberance and artful swing toward dragonflies. He found Vermont’s first Enallagma durum (Big Bluet). And on August 6, Kevin got another – the state’s first Tramea carolina (Carolina Saddlebags). Here’s his account and my own image of copulating Tramea carolina, from, yep, North Carolina.
After spotting a Giant Swallowtail in Loudonville, NY, this May, I fully expected them to make it to Vermont at some point this year. Sure enough one was spotted and photographed in Addison last week. This was all the encouragement I needed to search for one on my own. My first stop was the Bennington Dump. Before you scoff, know that reclamation work at the dump included prairie wildflowers planted by Taconic Tristate Audubon Society. I have found many interesting butterflies and dragonflies at the site.
With no Giant Swallowtails, however, I decided to check a small retention pond where I had found Libellula cyanea (Spangled Skimmer), a rarity in Vermont, a few weeks previous. Almost immediately I spotted a patrolling male Tramea carolina (Carolina Saddlebags). This is a Vermont record so I went about trying to voucher it. A good 45-60 minutes later, I was successful.
This got me curious about a site where I had seen many T. lacerata (Black Saddlebags) earlier this year. I decided to check a spot at South Stream. My luck was good. Three male T. carolina were patrolling and I noticed one tandem pair.
The southern air flow may have made the last few weeks uncomfortable but, they have given Vermont a few nice surprises in return. What’s next?
Dragonfly Swarms
Summertime … and the dragonflies are swarming. They’re flying at mountain summits, along ponds and over fields. Lots of folks are enjoying them. So here’s the scoop on swarms.
Most of what we’re seeing now amounts to swarm-feeding or swarm-foraging. July through August is peak season for the flights of the large “Mosaic Darners” in the genus Aeshna. (The derivation of this name is not quite clear but may have come from a printer’s error in spelling the Greek Aechma, “a spear.”) In any event, these are the big, dark dragonflies marked in pastel blues, greens and yellows. The old-timers sometimes call these “Devil’s Darning Needles.” They are most abundant at lakes and ponds with emergent vegetation. North America has about 16 members of this genus; 10 in Vermont. Pictured here is a pair of Variable Darners (Aeshna interrupta) copulating on my front porch.
So what’s happening in these swarms and why do they form? Well, basically, when they’re not having sex dragonflies spend a good portion of their day flying around, killing things and eating them. Swarms form around prey species, often small flies. Dragonflies in swarms can track and follow aggregations of prey species as they shift in location and abundance. And they can even locate food using past experience and topographical clues. One researcher in Costa Rica (Young 1980) noticed Roseate Skimmer (Orthemis ferruginea) gathering in good numbers to feed over trays of black-pepper berries fermenting and drying in the sun. The skimmers were feeding on fruit flies and other insects attracted to the berries. When the trays were removed, the Roseate Skimmers departed post haste. When empty trays were returned to the site, the skimmers returned to investigate, apparently keying on the visual clue as a source for food. Other causes for swarm formation include dragonflies and their prey gathering in the lee of an otherwise windy setting, for example, or in a sun-dappled clearing in the woods where evening light makes prey easier to locate (Corbet 1999).
I should also point out that I have been seeing an amazing dragonfly, Wandering Glider (Pantala flavescens), flying in swarms and individually in the past few weeks. About three inches long, Pantala is the color of gold and a flying machine. It is found on every continent except Antarctica. Its long, wide wings allow this dragonfly to cross oceans, making Pantala a champion flier among dragonflies, in many respect the albatross of insects. It is also steeped in mythology. Pantala, for example, is a symbol of courage and victory in Japan. Large numbers appear in Honshu (the nation’s main island) and Kyushu (the third largest island) around August 15, a date on which Buddhists believe ancestral spirits visit their homes. On August 13, 2009, Pantala flavescens invaded Montpelier, Vermont (where I have an office), probably numbering in the thousands. Since then Pantala is still flying in Montpelier but in lower numbers. Look for them from about 6 to 12 feet APL (above pavement level). Here’s a post, video and photos from a Pantala swarm I encountered in Michigan on July 24.
Migration is a different matter. Most adult dragonflies live out their lives at a single site – a pond, a bog, a river – over the course of days, weeks or, rarely, a few months. But some live long and migrate like birds. We see it mostly in the fall. In fact, birders often notice migrating dragonflies from hawkwatch sites. One of my best encounters came while birding on Monhegan Island, off Maine’s midcoast, in September of 2009. It was a river of dragonflies, almost entirely Common Green Darners (Anax junius) heading out to sea, southbound for who knows where. But we’re learning. Researchers are attaching tiny radio transmitters to Anax junius and other migratory dragonfly species in order to track their movements (Wikelski 2006). Others can catch a migrating dragonfly in, say, New Jersey, and by measuring trace concentrations of certain molecules (stable isotopes) in its tissue can learn about where it grew up. It turns out, among dragonflies, you are what you eat. What a dragonfly ate while growing up can give a biologist a clue to where it was born (or hatched in this case) no matter where or when it is caught by a researcher. With tools like these only now are we beginning to learn how far and for what reason dragonflies are migrating. I’ll cover migration in a separate blog post this fall.
If you want more, check out The Dragonfly Woman’s blog post on swarms. I heartily recommend this site. (She’s got a nice new post on aerial plankton.) The Dragonfly Woman is tracking swarms around the continent; you can even report your swarm!
References
Corbet, P.S. (1999). Dragonflies: Behaviour and ecology of Odonata. Essex, Harley Books, 829p.
Wikelski, M., Moskowitz, D., Adelman, J. S., Cochran, J., Wilcove, D.S., and May, M.L. (2006) Simple rules guide dragonfly migration. Biol. Lett. (2006) 2, 325–329
Young, A.M., (1980). Observations on feeding aggregations of Orthemis ferruginea (Fabricus) in Costa Rica (Anisoptera: Libellulidae). Odonatologica 9:325-328.
A New Vermont Butterfly
Breaking news. An alert observer, Ardys Fisher, discovered Vermont’s first official Giant Swallowtail (Papilio crestphontes) in Addison on July 30. This is the largest butterfly in North America. With trees and shrubs in the citrus family (Rutaceae) as its larval hostplant, Giant Swallowtail tends to have a southern distribution in the US. But it does wander northward. We’ve had unconfirmed reports of this butterfly in Vermont. But now the evidence is incontrovertible. Way to go, Ardys! That’s the proof above; Ardys’ husband Lionel got the photo. My photos of Giant Swallowtail, from the prairies of Missouri, are below. And here’s a link to the Butterflies and Moths of North America page on this species.
Hetaerina Heaven
Now here’s a lickable damselfly. (Yeah, you actually want to lick them as they dance along riverbanks.) I know of only two sites for Hetaerina americana (American Rubyspot) in my home state of Vermont. This elegant animal has an odd, scattered distribution across North America and is uncommon over much of the Northeast. So it was a joy to see clouds of them — thousands, really — along the Clinton River in southeastern Michigan yesterday. They perched on streamside vegetation, on rocks, on garbage on me. Males flew circles around one another in competition for perches. Despite their abundance, I saw none courting or copulating. Why? I know little of this species’ phenology in Michigan, but perhaps they were still early in the adult stage, not quite ready for, well, you know. Dragonflies and damselflies do require a bit of time at adults to feed and mature before copulation (in stark contrast to butterflies, which go right at it when they emerge). In any event, below is a male from yesterday and then a female, which I photographed a couple years ago in Missouri.
Saving a Rare Songbird
Each spring, across a small section of North America, dawn comes with an event witnessed nowhere else on Earth. It happens in a zone of mountainous and coastal forest sites scattered across southeastern Canada and the northeastern United States. As the day begins, these forests come alive with the swirling song of the Bicknell’s Thrush. Arriving after a 2,000-kilometer migration from wintering grounds in the Greater Antilles, the thrushes will breed and raise young in these forests, not far removed from population centers with millions of people. A scant four months later, they will depart and migrate south before the onset of winter. With each journey, north or south, Bicknell’s Thrush flies toward an uncertain future.
That’s an excerpt from a summary document I helped to prepare for the International Bicknell’s Thrush Conservation Group. The IBTCG just released A Conservation Action Plan for Bicknell’s Thrush. The plan’s four-page summary (400K PDF) offers a concise account of the threats and conservation actions planned for this amazing songbird. Please read it. Here’s my image of a Bicknell’s Thrush on a nest on Vermont’s Mount Mansfield.
A Swarming Welcome to Michigan
A dead deer and a shredded tire (not mine) were the “Welcome to Michigan” icons when I crossed the Ohio line on Interstate 75 south of Detroit. Ten miles later I pulled off at a rest area and official welcome center. Greeting me was a nice swarm of dragonflies. Here’s the video and images of the three species in the swarm: Anax junius (Common Green Darner), Pantala flavescens (Wandering Glider) and Pantala hymenaea (Spot-winged Glider).
From the Trail Today
The Path of a Century
BLOGGER’S NOTE: The Long Trail, Vermont’s 272-mile hiking path from Massachusetts to Canada, turns 100 this year. The birthday comes with a great book, A Century in the Mountains: Celebrating Vermont’s Long Trail, published by the trail’s caretaker, the Green Mountain Club. Having hiked the Long Trail end-to-end twice, with countless shorter hikes in between, I wrote the chapter on the trail’s natural history. But the Long Trail is Vermont. So my chapter is in many respects a concise introduction to the nature of Vermont. I’m taking a break from the blog in order to make progress on my book. I’ll post here about once a week or so for a while. Until then, here’s my chapter from A Century in the Mountains with a few of my photos (including a bobcat and my hobblebush slideshow). Read on, buy the book … then get outside.
By Bryan Pfeiffer
F
rom the summit of Mount Grant the nature of the Long Trail unfolds at a hiker’s feet. This lofty spot (3,623 feet above sea level) is about halfway between Massachusetts and Canada. Yet it boasts no particular celebrated status on the trail, unless, of course, you believe each step along this route is itself a celebration. In any case, Mount Grant is a fine spot to stop and ponder the diversity of life on the spine of Vermont – whatever flies, flutters, darts, jumps, scampers, walks, crawls, slithers, swims, grows, decays, or even only sits there beside this illustrious path.
Visible far to the south of Mount Grant is some of the Long Trail’s more gentle terrain, a high plateau where a hiker can swim in remote ponds and circumnavigate mysterious bogs. Southern trees and unusual plants, at least by Long Trail standards, like bitternut hickory and Goldie’s fern sprout here and there in few locations. And early hikers, in June, might find early hairstreak, a prize butterfly about the size of your thumbnail, colored in shocking cobalt blue and mint green marked with little orange lightning bolts.
Somewhere off in the distance to the north are the trail’s classic and most recognizable peaks. As hikers here walk atop Vermont, they pass tiny flowering plants more typical of the arctic than New England. And if that isn’t wild enough, one of the Northeast’s rarest breeding birds, the Bicknell’s thrush, with a swirling, fluty song, enjoys a rather exotic and promiscuous sex life nearby. Soon after departing this the elevated excitement, the route to Canada features descents into various dramatic notches and eventually crosses two major rivers, from which, as the Long Trail always seems to do, it rises skyward yet again into the mountains.
But for now, having attained that high perch on Mount Grant, or most any elevated point on this trail, do not forget to admire what is close. Here at your feet, or more likely beneath your boot, look for one of the trail’s certifiable marvels of natural history. It is called Marasmius androsaceus. It is a mushroom standing no taller than an inch or two, with a black hair-like stalk and a tiny peach-colored parasol cap.
Of course, few hikers ever notice Marasmius androsaceus. In the vast assemblage of rock, mineral, plant, animal and otherwise that constitute this path, a mushroom would seem ill-qualified as a poster child for an essay on the nature of the Long Trail. It certainly lacks the lofty status of pink lady’s slipper orchids or peregrine falcons or bald summits with big views. Yet once you discover the role of Marasmius androsaceus, and countless other natural riches large, small and in-between along this route, it should become obvious that most every step on the Long Trail is indeed a step to be celebrated. Spend a lifetime walking this long, green path and you will discover but a fraction of its natural secrets. read more…
Emperor Encounter
While I was out searching for dragonflies on the Huntington River near Jonesville, Vermont, on Sunday, a Hackberry Emperor (Asterocampa clyton) touched down briefly to puddle on a gravel bar. He did a loop de loop around my head, then he was gone. This is a rare butterfly in Vermont. We find it in the vicinity of its host plant, Northern Hackberry (Celtis occidentalis). Hackberry, a tree, makes it way into Vermont in the Champlain Lowlands and the Connecticut River Valley, then “inland” a bit along major rivers, including the Winooski and some of its tributaries. Where the tree goes, the butterfly may follow. This was the first Emperor I’ve found in Vermont. I didn’t have my camera. These two images, from different sites in Missouri, including my pant leg, are a nice reminder that butterflies are not marked the same above (dorsally) and below (ventrally). By the way, Hackberry (North America has six native species) was once a member of the Elm Family (Ulmaceae) but is now considered a Hemp (Cannabaceae).
Counting Butterflies
The rain picked a fine day to return. Today is the 11 Annual North Montpelier Butterfly Count, organized by the North Branch Nature Center.* When the sun peaks through, we’ll be counting every butterfly we see in a 15-mile-diameter circle centered in North Montpelier. It’s like a Christmas bird count, only you get to sleep in and need not wear seven layers of clothing. Here’s a Two-spotted Skipper (Euphyes bimacula). It’s a bog specialist here in Vermont, feeding as a caterpillar mainly on the sedge Carex trichocarpa. Skippers, considered the bane of butterflyers because so many skippers look alike, are now widespread, like little orange flames scattered about the landscape. Most are tiny, no more than three-quarters of an inch in length. Good field marks on this skipper include those faint white veins on the underside of the hind wings and that white margin along the abdomen. Females do have two spots on the upper side of the forewing, which you can’t see in my images here. Occasionally, an adult will alight on your pant leg (above) to lap up salt on a steamy day or drop onto a gravel road for trace minerals and salts. These guys are showing what we call a probing proboscis.
* As it turns out, the count was canceled today because of the rain. I’ll post an update when it’s rescheduled.