A Little Island Biogeography

Review_Islands_map

ISLANDS have fascinated people for a very long time. Think of creation myths like Turtle Island or the numerous accounts of catastrophic floods. Think of Odysseus’s misadventures among the Aegean Islands. Think of the vikings who discovered and settled Iceland and wrote the sagas. Think of William Shakespeare and the magical island of The Tempest. Think of Herman Melville and the grim, volcanic islands recounted in The Encantadas or Robert Louis Stevenson and the buccaneers and buried gold stashed inside the covers of Treasure Island. Here’s a list that could go on and on, yet, even curtailed, it’s an island list redolent of mystery and adventure.

Many early scientists, explorers, and naturalists expressed a penchant for islands, some as ardently as the storytellers. Most preeminent being Alfred Russel Wallace and Charles Darwin. Wallace collected insects and birds among the islands of the Malay Archipelago, wondering what might explain their distributions and variations. Darwin puzzled through similar oddities encountered on the many islands he visited during the five-year voyage of the Beagle, resulting…eventually…in his theory of natural selection. During the century and a half since Wallace and Darwin, numerous scientists have focused their research upon the natural laboratories that are islands—Ernst Mayr, E. O. Wilson, and Peter and Rosemary Grant to name but a few. The big story of island biogeography, its rich history and relevance to modern times, has been masterfully told by David Quammen in his magisterial book, The Song of the Dodo.

Biogeographers study the distribution of plants and animals—which species live where, and why—bringing to prominence the role geography plays in the process of evolution. Island biogeographers study the same thing, only with a focus on the more restrictive and clarifying setting of islands, delineating the special role isolation plays in the formation of new species.

Two main factors influence the formation of new species on islands: location and size. If an island is small or close to the mainland nothing too extraordinary happens. On the other hand, if an island is large or distant enough from other land masses so that vagrant species arrive only with great irregularity over great spans of time speciation is more likely to occur among the plants and animals that happen to make it to the island and that survive to establish populations. Extinction plays a role as well. As evolution’s unavoidable shadow, extinction reduces and subtracts and trims island diversity, this permanent negation creates an absence that new species might fill.


Pale Lichen Moth
Pale Lichen Moth
In August, I had the privilege to visit Mallard Island, an island of some renown on Rainy Lake in Minnesota, a mile or so from the Canadian border. The island is a lance-shaped skelf of bedrock, one and a half acres in size (an area roughly equal to that of a football field), covered in pine and lichen and moss. The island’s notability can be credited to Ernest Oberholtzer (1884 – 1977), who occupied the island for some forty years beginning in the 1920s. During those four decades, Oberholtzer constructed a number eccentric dwellings and outbuildings upon the island, built various stone walls, bridges, and gardens, amassed a library of more than 10,000 books, and helped protect a vast amount of wilderness, work that led directly to the establishment of Voyageurs National Park and the Boundary Waters Canoe Area Wilderness. And, near the end of his life, he created the Oberholtzer Foundation in order to preserve the rugged and secluded charm of his beloved island—and bring forward his conservationist legacy.

As member of a small group of people invited to stay on the island for one of the Oberholtzer Foundation program weeks, I arrived Sunday afternoon ready for six days of intense reading, new conversations, and an abundance of time out-of-doors. The focus of this week’s program, as laid out by the organizers, was on art and science. The purpose, and our purpose in participating, was to expand our views, to strengthen our resolve, to collaborate across the distances and differences, all with an eye to the economic and environmental struggles that we all are facing and which will only intensify in the years to come as human populations increase and resources dwindle.

Now, according to some people, powerful spirits inhabit Mallard Island. Inanimate objects like books are said to leap into your hands as if in magical apprehension of your wants or shortcomings. And while I do my best to respect the angels and demons encountered by others, I have to say right off that I’m a skeptic in my own sphere, content enough with the wonder-filled world as it is, finding any superadded spirit world unnecessary. Nonetheless, I’ll admit it can seem uncanny, in such a sweeping assemblage, to immediately find a book that is extraordinarily apt and directive. For instance, as soon as I had the opportunity to look at books I happened upon a copy of Shan Walshe’s Plants of Quetico and the Ontario Shield. “There are occasions when luck goes farther than wisdom” I’d read recently, and this is true. Thus I allowed my luck to direct my activities for the week. For the next few days I would unburden myself of the role of writer, turn truant from the island’s other books (as best I could), try my hand at some botany, conduct a little island biogeography.

Realizing full well that most island biogeography happens on oceanic islands not islands on freshwater lakes, I didn’t expect to discover any endemic species or any vast differences among these small islands. Rather I expected them to be similar and express only subtle differences. Separated by less than a mile of water from the mainland, having strong “land communication” to use Wallace’s term, the flora and fauna should be nearly identical across the islands and representative of the fire-dependent, northern forest ecosystems that covers much of the Canadian Shield. However, some small variations could be expected, reflecting the happenstance of slight differences in physical shape, human habitation and use, and microclimates.

I took photographs. I made lists. I mapped the flowers as if I were a bee. My entomological surveys consisted of two nights of mothing and various incidental encounters with other insects. My botanical surveys consisted of daily excursions and rambles: a hike on Crow Island, from tail-feathers to beak; fishing the circumference of Gull Island, noting the trees and shoreline vegetation; an east-to-west ramble the length of Mallard Island, pen in hand; an afternoon exploring Hawk Island; a paddle into the long, marshy bay of Grassy Island; a boat ride to Blind Bay in Canadian waters (thanks to the generosity of fellow naturalist Mary Lysne); ending the week with a second trip to Crow Island.


Scarlet-winged Lichen Moth
Scarlet-winged Lichen Moth
Midway through the week, on Wednesday afternoon, I visited Hawk Island. To get there I waded the narrow channel separating it from Mallard Island, shoes in hand, camera slung over my shoulder. Barefooted, I could feel the ridges and recesses in the bedrock. The stone underlying the islands had formed many millions of years ago. Those original rock strata had been broken, turned on edge, and scoured by glaciers. Only the stars overhead at night were older.

Once across the channel, the only way onto the island was up a steep rock face, so I climbed and entered the woods. My transect of exploration sliced across the middle of the island. Reaching the abrupt cliffs that define the south edge of this island (a pattern interestingly repeated on the other islands), I veered and puzzled my way to the eastern tip, where the bare rock thins and dips beneath deep lake water the color of iced-tea. From there I worked back. A few flowers on the wave-beaten rocks, Hedge Nettle and Grass-leaved Goldenrod, before the Jack Pine and Reindeer Lichen and mosses thickened as I climbed inland. In a small, mossy clearing, I came upon a beaver skull missing the bottom jaw, turned to reveal the upper teeth. The clean, white bone of the skull brightened the forest floor. Here was a reminder that there existed a time element to this timelessness; islands come and go; species evolve and go extinct.

On hands and knees I inched as close as I could to a shiny, brassy-green soldier fly that had perched on a blueberry leaf. After it flew, I sat back. A few deep breaths. A few hearty exhalations, sighs of satisfaction and gratitude for this time, for this place. Then I moved on, continuing this fine-scale perusal of the surroundings. I smiled at pixie-cup lichens so small that a single drop of rain would overfill one. I shook my head in wonder at the clubmosses so perfectly replicating the form of trees on a miniature scale. I made my way across a seemingly stochastic quilt of vegetation, and yet I knew that it wasn’t purely random, but patterned in subtle ways. Eventually I reached the edge of the forest where the bedrock drops away. Time to return to the other island. Though before I left, taking a final glance back, the forest produced a parting surprise, a ghost plant, a small clump of Indian Pipe.

Even as I began to learn the names and recognize certain patterns of occurrence, I was humbled by the sheer abundance and complexity of these small islands. Goethe once wrote of Rome that “the immensity of the place has a quieting effect. In other places one has to search for the important points of interest; here they crowd in on one in profusion… One would need a thousand styluses to write with. What can one do here with a single pen?” Wild, unbounded nature, not urban complexity, confronts one here and leaves one the task of organizing its subtle immensity into the simplicity of a few paragraphs. How does one write a long, slender island into an essay? A splinter of schist, a sliver of seed must be forced into a simple sentence that proceeds: noun, verb, stop. Or elaborated, the serendipitous occurrences of flower and insect and observer intersecting at a moment in time on an island gets written into a sinuous sentence, full of detours and wrong turnings, break downs and bad luck, or simple exuberance, the description going all out, on and on, forming a widening interior, fattening the page, where eventually the reader walks out of the forest and finds the shore at land’s end.


Painted Lichen Moth
Painted Lichen Moth
On Thursday, after some morning reading—sonnets by Conrad Aiken, a natural history of worm-lions by Morton Wheeler—I took oars from the rack on the side of the library and headed off on a return visit to Crow Island. I rowed past Japanese House on the westernmost tip of Mallard Island, then past Fawn Island, rounding the westernmost tip of Crow, doubling back into a small bay, beaching the boat at the landing, snug in a thicket of sweet gale. Once on land, I worked my way up to the sunlit outcroppings, hoping to find and photograph a Dragonhunter, a large dragonfly I’d seen flying and landing on the waterside ledges just the day before. When no dragonfly materialized, I fell into surveying the plants.

All week I’d stepped carefully around bumble bees nectaring on oregano that grew in thick patches in and out of the rock gardens on Mallard Island. Several times I stopped for a closer look at the handsome workers. Tri-colored Bumble Bees (Bombus ternarius), attractive yellow, orange and black bumble bees, are small, not much different in size than a honey bee, though fuzzier. Their abundance indicated a thriving population, with perhaps a number of hives located nearby. Now, as I prepared to leave, a very large bumble bee, much larger than the workers observed on the other island though patterned the same, buzzed by me and landed on the ground. It, also, had arrived on the island looking for something. I watched the bee as it searched about the pine needles and duff. It started to dig, disappearing into the dirt. How curious. My first thought was that it had entered a hive…but when no other bumble bees came or went, I realized that wasn’t correct. Then I remembered the abundance of bumble bees from the other island—the hidden hives—the workers working the oregano flowers, had succeeded in producing queens, the goal of their summer labors. Though it seemed early in the year, with next year’s summer certainly a long way off, this queen was likely searching out a hibernaculum, a safe place to wait out the winter and dream bumble bee dreams.

Here was a being adept at finding its way about the world. Another kind of island biogeographer in fact, locating suitable sites for hives, mapping the flowers. The shooting stars, which the other residents and I had witnessed in the night sky this week, were not more wondrous than this, nor more rare. To see this, to think about this had something to do with presence and absence…of leaving and longing to come back.


Black-and-yellow Lichen Moth
Black-and-yellow Lichen Moth
In the end, I realized that I would be returning home to my own small island of house & family. The small city lot on which our house sits surrounded by so many groomed and lawn-care-tended plots is certainly a kind of island refuge for insects and weeds. And the city parks and college natural lands that I often visit, while not islands surrounded by water, are engulfed by vast acreages of agricultural and urban/industrial development (for many plants and animals a far more treacherous crossing than water) making them islands as well. In fact, our increasingly fragmented landscapes make islands everywhere. Which is the very reason the science of island biogeography plays an increasingly important role in wildlife conservation and preservation.


A quick note about the following list: The first and most obvious caveat is that the list is not complete; I missed and overlooked many species, nor did I survey each island equally, nor did I include animals and insects. Secondly, links are provided for photo observations that have been submitted to iNaturalist.org, a crowd-sourced species identification system and database. If you notice something that’s been misidentified please let me know.

MallardIsland_Smithsonian_profile

Review Islands Flora

TREES & SHRUBS
Jack Pine (Pinus banksiana) *
Eastern White Pine (Pinus strobus) *
Black Spruce (Picea mariana)
Paper Birch (Betula papyrifera)
White Cedar (Thuja occidentalis) *
Common Juniper (Juniperus communis) *
Chokecherry (Prunus virginiana)
Alder (Alnus sp.)
Serviceberry (Amelanchier sp.)
Velvetleaf Blueberry (Vaccinium myrtilloides) *
Creeping Juniper (Juniperus horizontalis)
Beaked Hazel (Corylus cornuta)
Smooth Sumac (Rhus glabra) *
Balsam Fir (Abies balsamea)
Meadowsweet (Spiraea alba) ‡
Sweet Gale (Myrica gale) ‡
Bebb’s Willow (Salix bebbiana)

FLOWERS & Other Plants
Grass-leaved Goldenrod (Euthamia graminifolia) ‡
Field Goldenrod (Solidago nemoralis)
Northern Bugleweed (Lycopus uniflorus)
Wild Sarsaparilla (Aralia nudicaulis)
Dotted Knotweed (Persicaria punctata)
Water Smartweed (Persicaria amphibia)
Crested Arrowhead (Sagittaria cristata)
Marsh Skullcap (Scutellaria galericulata)
Fringed Loosestrife (Lysimachia ciliata)
Swamp Candles (Lysimachia terrestris) ‡
Floating Bur-reed (Sparganium fluctuans)
Indian Pipe (Monotropa uniflora)
Pussytoes (Antennaria neglecta)
Common Snowberry (Symphoricarpos albus)
Pearly Everlasting (Anaphalis margaritacea)
Bearberry (Arctostaphylos uva-ursi)
Silverleaf Cinquefoil (Potentilla argentea)
Marsh Woundwort (Stachys palustris)
Bull Thistle (Cirsium vulgare)
Harebell (Campanula rotundifolia) ‡
Pale Corydalis (Capnoides sempervirens)
Canada Hawkweed (Hieracium umbellatum)
Wild Columbine (Aquilegia canadensis)
Checkered Rattlesnake Plantain (Goodyera tesselata)

GRASSES, SEDGES, and RUSHES
Slender Rush (Juncus tenuis)
Woolgrass (Scirpus cyperinus)
Bur-reeds (Sparganium)

FERNS, MOSSES and CLUBMOSSES
Spinulose Wood Fern (Dryopteris carthusiana)
Rusty Woodsia (Woodsia ilvensis)
Wood Horsetail (Equisetum sylvaticum) *
Rock Spikemoss (Selaginella rupestris) *
True Mosses (Bryopsida)
Ostrich-plume Moss (Ptilium crista-castrensis)
Prickly Tree Clubmoss (Dendrolycopodium dendroideum) *

LICHENS
British Soldier Lichen (Cladonia cristatella)
Common Powderhorn (Cladonia coniocraea)
Gray Reindeer Lichen (Cladonia rangiferina)
Mealy Pixie Cup (Cladonia chlorophaea)
Red-fruited Pixie Cup (Cladonia pleurota)
Speckled Shield Lichens (Punctelia sp.)
Rock Tripes (Umbilicaria sp.)

* Fire-dependent indicator species
‡ Inland Lake with Boulder Shore indicator species

    Books referenced:

MacArthur, R. H. and E. O. Wilson. The Theory of Island Biogeography. Princeton Landmarks in Biology Edition. 2001
Minnesota Department of Natural Resources. Field Guide to the Native Plant Communities of Minnesota: the Laurentian Mixed Forest Province. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. MNDNR Saint Paul, MN. 2003.
Quammen, David. The Song of the Dodo: Island Biogeography in an Age of Extinctions. Scribner. 1996.
Walshe, Shan. Plants of Quetico and the Ontario Shield. University of Toronto Press. 1980.

The Vicinum Waltz

Autumn Meadowhawk ovipositor
Ever since reading James S. Walker’s article on the egg-laying behavior of Autumn Meadowhawks (Argia Vol. 24, No. 3), I’ve been keen to take a closer look at this behavior myself. I had observed Autumns ovipositing in the past, but always from a distance. This last weekend, the first weekend in October, I finally got my chance. After several days of wind, rain, and temperatures in the low 40s, the sun returned. The transition was dramatic, from completely overcast to clear blue skies in less than an hour. By the time I reached the shore of Bass Lake, a small kettle lake nestled into the wooded hills of Maplewood State Park in western Minnesota, the red dragonflies where out in force. These were mostly Autumn Meadowhawks (Sympetrum vicinum) and Saffron-winged Meadowhawks (Sympetrum costiferum), though I did see one White-faced Meadowhawk (Sympetrum obtrusum) as well. As I made my way away from the trail along the shore of the lake, a darner flew past carrying something large. When it grabbed a perch in a nearby tree, I moved in for a closer look: a female Variable Darner (Aeshna interrupta) eating a female Autumn Meadowhawk. Well, as John Caddy recently reminded me, everybody loves meadowhawks!

Further down the shore the red dragonflies reached rather epic numbers. If I stopped and stood still, Autumn Meadowhawks landed on the brown, sun-warmed leather of my jacket. Every exposed rock or fallen log hosted numbers of both Autumn and Saffron-winged Meadowhawks. Around one particular stump, the flight and tussle of competing males for good perching spots looked almost like a swarm of bees.

At the shoreline, a moss-covered log attracted several tandem pairs of Autumn Meadowhawks. I settled in close-by to watch. Right away I noticed a peculiar back-and-forth movement as the pairs dipped to the moss on the log then backed-up and dipped to the surface of the water. None of the other meadowhawk species attempt anything so complex. What the Autumns were doing seemed to require a great degree of coordination between the pair. However, the dips and hovers happened too quickly for me to get a good idea of the sequence of events, so I shot a few short videos using my camera so that I could examine them later.

The video posted here includes, at the end of it, several clips that have been slowed down to show the sequence of movements involved. This sequence is repeated over and over by each tandem pair. It’s hard to know which step in the sequence should be designated as the first. For convenience sake, I’ll begin with the hovering step. At this point the female has a bead of water held in position at the tip of her abdomen, something akin to a drop of water held at the end of a straw. It’s believed that while hovering the female adds eggs to this bead of water. (A close up photo of the moss on the log revealed a splattering of dragonfly eggs, which would seem to support this idea). Next, it seems the male initiates a headlong dive toward the ovipositing site, in this case the moss covering the log. He pulls up at the end of the dive, whipping the female against the moss. The force of this strike dispels the water droplet loaded with eggs onto the vegetation. After this is accomplished it seems the female initiates, by flying backwards and tugging the male, a much more gentle dip to the surface of the lake to pick up a new bead of water. The pair then hovers, rising and moving backward, regaining and hesitating at the initial position before starting the next cycle of steps in the vicinum waltz.

While it is difficult to know for sure whether the female or male dragonfly initiates the different steps in this sequence, or even how they might go about communicating with one another, it is obvious that some kind of cooperation is involved in this complex behavior. While filming the video, one tandem pair decided to take a break, leaving the ballroom floor to perch on my knee. I noticed right away that the female still carried a big bead of water on the tip of her abdomen and luckily was able to get a fairly decent close-up photo (posted at the top of this page). If only there had been an egg visible inside that droplet! The use of water in ovipositing, seemingly a necessity in this instance, helps explain why Autumn Meadowhawks are associated with permanent ponds and not temporary ponds, the latter tending to dry up by this time of year. It would be very interesting to know if the closely related Spot-winged Meadowhawk (Sympetrum signiferum) oviposits in a like manner, though its range is so limited in the US that I suspect no one has even observed it ovipositing.

Mute Objects of Expression

Dragonfly wing by Vicinum
Dragonfly wing, a photo by Vicinum on Flickr.

April 3, 2013. Windy, temperature in the mid to lower 40s, increasing cloud cover throughout the afternoon. When the forecast predicted a high of 50, I had hoped for the kind of spring day that might call forth the first butterflies, but it didn’t happen—too windy, too much snow on the ground, not enough sun to tip the scales from winter to spring. I went for a short walk anyway, almost out of spite.

I chose to look around the trails and woods on the south-facing slopes below St Olaf. The prairie planting outside the parking lot, beaten flat by winter snow and ice, made for easy walking. Instinctively, I rounded the margins of several small catchment ponds, drawn to the open water. From the ponds I climbed across a few expanses of snow to reach the woods. There was no hope of finding anything flying—too cold, too cloudy—so I made for a tree, upright but dead, to look for beetles, its disassembling branches scattered on the ground like so much wreckage.

Examining a fallen branch, prying off a loose layer of bark, I found a dragonfly wing tucked into a narrow cavity, then, a few inches away, a second wing, in a separate chamber. I face this discovery in silence. The sun mumbled in my face. The wind jabbed its fingers into my ears. How did these get here? I wondered. Images, the mysterious museum pieces of memory and imagination, flashed into existence, sequentially. A suitcase. A room full of books. An empty rocking-chair. A broken porch swing. Forgotten storm windows. Glass containers on display in an out-of-business antique store. A still life of dusty objects in the attic of an abandoned house. Then words, the worker ants of the mind, began to arrive; as if from habit, they rose from the deep recesses and unknown tunnels of language. Sawdust. Though there was no saw, only the rasping jaws of beetle larvae, horntail grubs, and carpenter ants. The soft rot following fungal expeditions through the solid wood. Dizziness. Disorientation. Not sadness.

The first wing, more exposed to the elements, was tattered, the transparent cells clouded and opaque, and beginning to crumble like an ancient codex into the wood chips. The second wing, better protected beneath the bark, sparkled in a sheath of dew. I’ve seen a derelict factory that looked like this, dull sheet-metal siding, long tiers of multi-paned windows with much of the glass broken out, providing passage for pigeons. “Factory windows are alway broken,” wrote Vachel Lindsay. The cells of the wings—the rows, the columns, the groupings—have become a periodic chart of the elements of oblivion.

Most likely ants had carried and pulled the wings in as far as they could. Their tunnels became too narrow to admit them further, so the wings became decorations, septums dividing the antechambers at the entrances to their nests. The veins of the wings became ladders and bridges that allowed passage into previously unreachable rooms of reality, a cubist artwork on the order of Robert Delaunay’s painting ‘Simultaneous Windows on the City.” Here was the insect equivalent of Marcel Duchamp, artfully presenting the detris of the world. Here was a scavenging Joseph Cornell placing the found objects of the world into a box. Each wing became a relic, of blue skies, of fleeting life. And surely both wings qualify as one of Francis Ponge’s Mute Objects of Expression.

Then, from the parking lot above me, out of my line of sight, voices of students or professors skittered over the snow drifts and into consciousness, sounding almost like bird song, before the slam of car doors, before the spark of engines, started me toward home.

Dragonfly wing

Sand Dunes State Forest

Azure Bluet (Enallagma aspersum)Sherburne National Wildlife Refuge June 30, 2012
Azure Bluet (Enallagma aspersum)
Sherburne National Wildlife Refuge
June 30, 2012

One afternoon this last summer, while the rest of my family went boating and water skiing at my brother-in-law’s cabin on Elk Lake, I had the opportunity to visit a few wildlife refuges south of the lake scattered throughout the Sand Dunes State Forest. The dunes, that give this area its name and make it a rather unique ecosystem, were deposited at the shore of a large glacial lake. Like most dune ecosystems, this area of sandy prairie and oak savannah is extremely fragile and very little of it, if any, remains entirely intact. Still, some big efforts have been made, and are still being made, to set aside and restore large tracts of land. Having never visited any of these refuges before, I was eager to explore them.

Driving south from Elk Lake, I couldn’t help but note some similarities between this landscape and the tall-grass aspen parkland in northwest Minnesota where I had spent some time the previous summer. The possibility of discovering a remnant population of Red-veined Meadowhawks (Sympetrum madidum) suddenly fired my imagination. As I stepped from the car to explore a parcel of restored prairie, just upslope from the St Francis River, a golden-hued meadowhawk flew past me and my pulse raced as I inched toward the small bush where it had landed. For a few moments longer, fancy held the upper hand, while I allowed this dragonfly to be a female Red-veined Meadowhawk, but I finally had to concede to reality, allowing it to be a young female Variegated Meadowhawk—a look alike in some ways, but far less of a surprise, especially given the vast numbers of this species observed during spring migration earlier this year. This particular dragonfly had to be the offspring of that earlier generation of migrants. A little ways off, sharing the top of a small tree with a Halloween Pennant, another migrant made an appearance, a Red Saddlebags (Tramea onusta).

My next stop was the Uncas Dunes Scientific and Natural Area. This SNA was established in 1989, following the rediscovery of the Uncas Skipper (Hesperia uncas) in 1983, a butterfly rarity that had been found in this vicinity two decades earlier, in 1961, but had been, assumedly, extirpated at some point after that. This apparently is the case once more as I can find no record of the butterfly after the late eighties. The last record I was able to locate is an online photograph of a pinned specimen, a female collected on June 29, 1989, at the Elk River Dunes. This specimen along with another from 1967 are held at the McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida, (Gainesville, FL, USA). This segregated population, a possible relic from the post-glacial thermal maximum (ca. 8000-4000 B.P.) when major vegetation zones shifted well east of their present positions, is located many hundreds of miles east of nearest populations in South Dakota. I was visiting at the right time of year—who knows, maybe I’d get lucky…

Not more than twenty or thirty yards into the southeast unit of the SNA, I interrupted a thread-waisted wasp as it was carrying its anesthetized caterpillar back to its burrow. The startled wasp (most likely Ammophila procera given the large size of the wasp and the large size of the prey) abandoned her caterpillar and flew a few feet away where she plopped down on the sand, splayed out flat as if to hide. The caterpillar, larva of the speckled green fruitworm moth (Orthosia hibisci), lay in the middle of the trail alive but unable to move. It was very large, longer and many times heavier than the wasp. I watched for a while, taking a few photographs, but the wasp made no move to reclaim the caterpillar. However, when I returned after my walk, the caterpillar was gone, no doubt sealed carefully underground and dotted with a soon to hatch egg. Howard Ensign Evans summed it up well in Wasp Farm, “I don’t know of anything more exciting than to see a large Ammophila running over the ground with a huge caterpillar slung beneath her and then to follow her to her nest and watch the proceedings.” I had forfeited the most interesting part, being bent on finding butterflies, but still it was exciting just to have encountered this wasp.

The trail, crowded by rebarbative banks of poison ivy, shadowed by overarching oaks, led eventually to the SNA. Along the way I was bothered by horseflies and deerflies; actually more than bothered, I was bullied, badgered, and bitten to the point where looking for dragonflies and butterflies became difficult. The flies tried my nose, my eyes, my mouth, and made consistent contact with my blood at the back of my neck. I flinched at the low-buzz of a super-sized horsefly near my right ear and was pleased to see that it was really a Common Eastern Pondhawk flying off with a captured fly. I was doubly pleased when, further along the trail, several Racket-tailed Emeralds decided to tag along and nibble away at the fringes of the deerfly cloud that had amassed about my head. Another insect I was delighted to see, for similar reasons, was the white-bearded and silver-tipped robber fly, Efferia albibarbis. No doubt this large insect predator was dining on the swarm of tabanids and had a gullet full of dissolved horseflies and deerflies, or at least I hoped so.

As I walked out of the SNA, having seen no skippers, I couldn’t help but associate the shotgun-blasted ladyslipper on the scientific and nature area sign near the entrance with the slower, but more methodical violence done to the native flora and fauna of this place as it was developed and farmed over the last 150 years. And I wondered if anyone would ever spot the Uncas Skipper along this trail again.

I did, eventually, track down a few skipper butterflies. First, at a trail head north of Ann Lake, where a quick search of the parking lot and adjacent road ditches along Highway 4 yielded a few Tawny-edged Skippers (Polites themistocles) nectaring at a clump of alfalfa. Not the Uncas Skippers I’d hoped for, but nonetheless a new species for me. And then, a few miles away, in the Sherburne National Wildlife Refuge, at the canoe access to the St Francis River off Highway 1 about a mile south of Elk Lake, I caught sight of a chocolate-brown Northern Broken-Dash (Wallengrenia egeremet) nectaring on hoary alyssum in the middle of a small expanse of sandy prairie.

In that same expanse of prairie, which the canoe access trail passed through, there were also a lot of dragonflies—Eastern Amberwings, Frosted Whitefaces, Calico Pennants—and a great big surprise of a damselfly—an Azure Bluet (Enallagma aspersum). This was, so far as I knew, only the fourth time this species had been recorded in the state. Strangely the records are widespread: Albert Lea, Duluth, Webster, and now here, near the town of Zimmerman, in central Minnesota. I spent a good amount of time photographing this damsel, a strikingly blue male.

In addition to the time spent contemplating the Azure Bluet, I spent a good deal of time trying to get a good photo of a grass-carrying wasp (Isodontia mexicana) that was nectaring on the prairie flowers. This big wasp was extremely active, rarely staying put or standing still as it rooted around in the radiating white blooms of New Jersey Tea (Ceanothus americanus), pollinating like crazy.

White-bearded Robberfly (Efferia albibarbis) Uncas Dunes SNA, Sherburne County June 30, 2012 male
White-bearded Robberfly (Efferia albibarbis)
Uncas Dunes SNA, Sherburne County
June 30, 2012
male

The Last Dragonfly

Dia de los Muertos seemed a fitting day to go looking for the year’s last dragonflies. Lo and behold I found the caballitos de diablo, still very much alive. Crazy to think that this autumn meadowhawk has seen the first snow come and go. (Photo taken in November 1, 2012, in Northfield, Minnesota)

St Olaf Natural Lands, Northfield, Minnesota