Mink

thoughts on a widespread local mustelid

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Right after a little (belated) snowfall in early December, I chanced to be prowling around some ponds in the Mendenhall Glacier Rec Area. Mink feet had been there before me, leaving crisply defined footprints in the trails. That mink mostly kept to the foot paths rather than humping over and under the frozen grasses, but made occasional forays to the edges of the almost-frozen ponds. Mink –and deer, bear, and porcupines—often use ‘our’ trails, where there is easy going; snowshoe hares don’t seem to do so very often.

Mink can climb very well and have a rotatable ankle joint that lets them come down a tree headfirst (like a squirrel). But they usually hunt on the ground and in shallow water, both salt and fresh. They swim well, with partially webbed toes, and can dive several meters deep. Their fur is water-repellent. They live all over Alaska, except for some islands and the very far north, reaching high densities in Southeast (except where heavily trapped).

Mink-sleeping-by-bob-armstrong
Photo by Bob Armstrong

Dens are usually near water—in hollow logs or burrows, under tree roots, often in an abandoned den of some other animal, such as a beaver or marmot. The video cam at the visitor center sometimes catches a mink exploring even the occupied beaver lodge in Steep Creek. Mink aren’t likely to use a burrow that belongs to an otter, however, because relationships between mink and otter are generally hostile. They share many of the same eating habits, and otters sometimes kill and eat mink.

Mink are opportunistic foragers for meat of all sorts—everything from bugs and earthworms to fish, small mammals, and birds. When foraging in the intertidal zone, they take crabs, clams, little fish, and snails. Mink also gobble up bird eggs and carrion, including salmon carcasses. Cannibalism sometimes occurs. A big male mink sometimes may take down a hare or muskrat or a sitting bird twice its own size.

Mink-with-gunnel-by-bob-armstrong
Photo by Bob Armstrong

Mink are fierce enough to tackle prey that is bigger than themselves. Years ago, however, my old cat who was an experienced hunter, observed a mink travelling on the other side of my home pond and got wildly excited. She could hardly sit still at the window, bumping into the glass, whining, champing her teeth, twitching all over. Little did she know that she would become mink lunchmeat, had she been outdoors and free to engage with this so-attractive creature.

Mating, for mink, occurs in early spring and young are generally born in June. There may be as many as ten of them in a litter, but four or five would be more usual. Both male and female mate promiscuously, so litter mates may have different fathers. Mating often begins with a rough and no doubt boisterous fight that may leave the female with some wounds. The male then grabs the female by the back of the neck and they copulate, often several times. Copulation is a prolonged process, sometimes lasting as hour.

Eggs are fertilized over a period of several days but do not begin to develop immediately. Mink, along with other members of the weasel family, delay the implantation of the fertilized egg in the wall of the uterus. That egg may float around for several weeks before attaching to the uterine wall, getting a blood supply (via the placenta) from the mother, and starting to develop. From implantation to birth takes only about a month but, as a result of delayed implantation, there can be as many as three months between copulation and birthing.

Kits are born blind, deaf, thinly furred, and toothless. They get their milk teeth after about sixteen days, and their permanent teeth begin to erupt after about six weeks. Their eyes open at a little over three weeks and weaning occurs at about five weeks. Kits start hunting, along with the mother, at about eight weeks of age, but become independent after another month and disperse to find their own home ranges. They mature by the next spring and can breed then.

American mink were introduced to Europe decades ago and now occur across much of northern Eurasia. They compete with the smaller, native Eurasian mink, whose populations have declined dramatically from that competition and many other factors. Mink were also introduced, more recently, to southern South America, which previously lacked any similar predator—no doubt the expanding mink populations cause consternation and carnage among the native riparian and shoreline birds there.

Eagle eyes

the complexities of visual acuity in birds

We say that a sharp-eyed person has ‘the eyes of an eagle’. Eagles are reported to be able to spot a rabbit from a distance of two miles. Eagles, hawks, and many other birds are well-known for their visual acuity. Acuity is defined as the ability to discriminate two points as separate entities from a distance; more particularly, it refers to the ability to discern shapes.

For that ability to be brought into play, however, the eye must be able to focus. In humans and other mammals, visual focus is achieved by changing the shape of the lens, bending the incoming light rays so they hit the retina. But in most birds, both the lens and the cornea can change shape; that potentially gives such birds an especially good range of focus (diving birds are an exception—the cornea has the same refractive index as water, so changing its shape would have no effect on focus, and only the lens is used in these birds).

How does visual acuity work?

Visual acuity depends on the function of three interconnected but distinct levels. The first level is the retina, where millions of photosensitive cells line the back of the eye. In the second level, those cells are connected by short nerve fibers to nerve cells that are sometimes clustered together in ganglia, where they are often connected to each other. And in the third level, those ganglia are connected, via more nerve fibers, to the optic centers of the brain via the optic nerve, essentially a cable of millions of long nerve fibers. Here is a brief rundown about those three functional levels (structurally, the peculiar arrangements in vertebrate eyes are more complex and better omitted for present purposes).

Level 1. There are two kinds of photosensitive cells in the retina. Rods (so-called for their shape) that are very sensitive and work well in dim light; the eyes of nocturnal birds and many mammals have mostly rods. Cones (spindle-shaped cells with a cone-shaped point where the photosensitive pigments are located) work best in relatively bright light and provide sharp resolution and color vision. Birds typically have four kinds of cone cells, sensitive to red, green, blue, and UV, while mammals have only three kinds (no UV). Human eyes have millions of cone cells; avian eyes can have more than that, the numbers depending on both the size of the eye and the density of cones.

Cone cells are densest in an area of the retina called the fovea, which shows up as a small dip in the retinal surface. The eyes of humans and other primates have one fovea, as do most birds. Some mammals and birds (e.g., chickens and quail) have no fovea at all. Terns, swallows, swifts, hummingbirds, hawks and eagles, and kingfishers are all reported to have two foveas in each eye. One fovea deals with binocular vision aimed at a target, as when a hawk, kingfisher, or a swallow is pursuing its prey; the other deals with sideways monocular vision for spotting prey at a distance.

Level 2. The number of cone cells connected to a ganglion varies greatly. In the fovea, there may be just one cone per ganglion, but in the rest of the retina, the ratio might be a hundred cones to one ganglion (for example). Clearly, the more cones connect to a single ganglion, the less precise the visual resolution is likely to be. However, within a ganglion, the nerve cells sometimes inhibit each other or perhaps interact in other ways, so the cone/ganglion ratio is not the only factor.

Level 3. The long fibers of the ganglia transmit signals to the brain, which obviously must be wired to somehow interpret and make use of the incoming information. On the way to the interpretive centers of the brain, the optic nerves of vertebrates partially cross, such that some of the nerve signals from the left eye are delivered to the right side of the brain, and some of the signals from the right eye are delivered to the left side of the brain. The proportion of nerves that cross varies among species. This may be related to, among other things, the ability to coordinate movements of the limbs. Many birds are reported to be able to sleep on one side of the brain, while keeping awake and alert (with the eye frequently open) on the other side. Some individuals exhibit a preference for one side or the other. Siamese cats, noted for their usually crossed eyes, are said to have a defect in the optic-nerve crossover that makes the eyes try to compensate for the faulty signals.

Sharpness of vision may be assisted by other adaptations of the avian (but not the mammalian) eye. For instance, many day-active birds have oil droplets in the cones of the eye. The droplets are red, yellow, or clear; different kinds of birds and even birds in different populations of the same species may have different oil droplets. The droplets are light filters that can change the light rays that actually reach the retina. For example, they can narrow the range of wavelengths registered by the cones, increasing the color contrast. Sharpening the color contrast might improve discrimination of shapes in some circumstances.

Visual acuity is a matter of spatial resolution. But many birds also have excellent temporal resolution; they can process temporal changes in light very quickly. For comparison, humans cannot detect separate light pulses that flicker faster than about fifty times per second—faster flickers are just a blur to us. But birds can process fast flickers and rapid movements more quickly than we can. This may allow them to register wing beats of a prey insect, for example, or detect the location of twigs and branches as they fly through the tree canopy.

Fungi and Wildlife

animal harvesters of fungal delights

Fungi are made up of vegetative parts, which are filamentous structures that typically lie underground, and reproductive parts, which take various forms, sometimes finger-like or shelves, or commonly as mushrooms with a stalk and a cap. But some fungi never produce above-ground parts; the small, round or lumpy reproductive structures are underground—these are known as truffles.

Fungi reproduce by means of spores—each tiny spore containing the makings of a new individual. Most fungi, such as ordinary mushrooms, disperse their spores aerially—releasing the mature spores from the mushroom cap to vagrant breezes in the forest understory. Truffles do it differently: they rely on small mammals to dig them up and eat them, passing the spores through the digestive tract and depositing them in feces.

Here in Southeast, there are two major harvesters of truffles: the red squirrel and the flying squirrel. The red-backed vole also does this and other small mammals may do so occasionally. These rodents also harvest typical mushrooms, sometimes caching them, to be eaten later, after they dry. Red squirrels do this very regularly; flying squirrels in other regions cache many kinds of food but apparently they have not been recorded to do so in Alaska.

squirrel-with-mushroom-by-bob-armstrong
Photo by Bob Armstrong

The caloric content of fresh mushrooms is low, far lower than that of nuts and seeds. However, dried mushrooms compare more favorably, although they still average only about two-thirds of the caloric content of conifer seeds. Mushrooms are very low in fat, compared to spruce and hemlock seeds, but they can be a pretty good source of carbohydrates and protein, especially when dried. They may also provide an assortment of micronutrients such as vitamins and minerals. Fresh mushrooms can be a source of water during season dry periods.

However, the actual food value of fungi to rodent consumers depends in part on the intake rate. Taking a bite of mushroom or truffle is quick and easy. But when eating conifer seeds, squirrels have to peel back the cone scale and trim the membranous ‘wing’ from each seed before eating it. Although squirrels are remarkably fast at extracting conifer seeds from a cone, it still seems that the food intake rate would be slower than when eating fungi. The actual food value also depends on how efficiently a squirrel’s digestive process extracts energy and nutrients from the material that is ingested. Some studies of squirrel diets suggest that the digestibility of fungal tissue is considerably less than that of conifer seeds. Nevertheless, squirrels regularly eat fungi, so there must be sufficient reward to make it worthwhile.

The relationship between truffles and squirrels (and voles) is mutualistic—the mammals get dinner and the truffles disperse their spores. For truffles, the relationship is obligatory; they are dependent on small mammals for spore dispersal. For the rodents, the relationship is more variable, depending in part on the availability other food sources (for example, squirrels might eat more truffles in years when the cone crop is poor). Mushroom-producing fungi sometimes get spores dispersed by rodents that harvest mushrooms; the spores ingested are viable after passing through the rodent’s guts, so in addition to the normal, aerial means, the fungi benefit from rodent assistance. This amounts to a casual sort of mutualism in which both parties benefit but the relationship is not obligatory for either one (in contrast to that for truffles).

Now the plot thickens! Many fungi, both truffles and mushrooms, are mycorrhizal—forming mutualistic relationships with the roots of various plants. The plants provide carbohydrates to the growing fungi and the fungi supply various nutrients to the plants. In most cases, both participants in the relationship grow better with the partner than they do alone; in some cases the relationship is obligatory to at least one of the partners.

Thus, in this network of interactions, one well-developed mutualism (the fungus-plant relationship) intersects with another one (the rodent-fungus relationship). Something for everybody! A nicely tangled web!

September leaf colors

bright highlights in an evergreen landscape

fall-color-by-bob-armstrong
Photo by Bob Armstrong

Juneau ‘leaf-peepers’ don’t have to travel to the upper Midwest or New England for a view of lovely fall colors. This fall there is a pretty good show right here. Although the somber greens of the conifers dominate the landscape, a good color spectrum from yellow to orange to red and pink and even purple can easily be seen.

Returning to the Valley from a hike out the road on a drizzly day when the clouds sat low on top of Benjamin Island, I saw several places along the highway where the golden-yellow leaves of cottonwood seemed to light up the whole area. Patches of fireweed provided flaming scarlet mixed with other shades of red. Across the highway from the Methodist camp, the roadside shrubs and small trees made a splendid pastel expanse of glowing yellows and pinks. Dogwood shrubs sometimes offered a spectacular array of reds and the broad yellow and gold leaves of devil’s club brighten the understory. Highbush cranberry can do it all–yellow, orange, bright red, pink—sometimes even on a single leaf. Closer to the ground, dwarf dogwood and low-bush blueberries do the reds and purples.

The visual color show happens when the leaves of deciduous plants senesce (deteriorate with age) in the fall. The vascular connection between leaf and stem is gradually closed, shutting off the supply of water and nutrients to the leaf and slowing the passage of materials from the leaf to the rest of the plant. Photosynthesis slows and the green pigment (chlorophyll) that does the work of making carbon dioxide and water into carbohydrates breaks down. As it breaks down, leaves lose the green color and the yellow and orange pigments are exposed; they were there all along, capturing light energy and passing it on to chlorophyll for photosynthesis. Chlorophyll is broken down by complex processes that are still being elucidated, but apparently some of the break-down products are still photo-reactive and perhaps potentially damaging, unless quickly de-activated or protected in some way. Meanwhile, the plant retrieves any remaining carbohydrates and nitrogen-containing products of breakdown before the vascular connection closes completely and the leaf drops.

What about the red colors in fall foliage? In most plants, they come from anthocyanins, synthesized toward the end of the season during leaf senescence, using some of the carbohydrates made by the leaf. Anthocyanins account for the reds, pinks, and purples—the hue depending on acidity within the leaf, which depends, in turn, at least partly on the accumulation of carbon dioxide in the leaf when photosynthesis is slowed. It is thought that warm sunny days and cool nights in fall favor the development of red foliage, so our unusually nice September weather might have contributed to the color show this year. I think we can see this effect sometimes in a single highbush cranberry shrub: the side of the bush exposed to light and dropping temperatures at the edge of the woods can be far more colorful than the other side of the same bush that is more protected under the tree canopy.

The functions of anthocyanins have been a subject of much discussion in the literature, but it appears that in autumn leaves they may have a protective function, defending the last days of photosynthesis and protecting from the possibly unstable, over-reactive products of chlorophyll breakdown from too much sun. There may be other physiological functions as well, still to be described.

Many questions remain. For instance: Why do some plants produce only yellow autumn leaves and not red ones? Do they have some other way of accomplishing whatever the anthocyanins do? An interesting comparison comes from quaking aspen, a relative of cottonwoods, in which some clones do make red or orange leaves. Also, willows usually make yellow leaves, but occasional some willow trees make lots of red leaves. Do they all have that capacity but just aren’t triggered to make red, or do only some willow trees have the capacity? And there are the alders, whose leaves invariably just turn brown. And a fundamental question: How does a plant decide when to shut down photosynthesis—there are easily observable differences among individuals of the same species, some retaining green leaves much longer than others. Stress from drought or insect attack might encourage a particular plant to shut down for the season, but what, specifically, are the mechanisms of this response?

Then there are the ferns, for which I have found little information about fall colors. But there is considerable observable variation. On one walk, there were wood ferns with whitish fronds, bracken with dark or light coppery fronds, and lady ferns all black, while in another area, lady ferns were tawny.

There’s no end to natural history questions; one answer just leads to another question! What fun! If we knew it all, there would be nothing left to provide surprises and discoveries.

September

delights of a season of slowdown

In September, the natural world slows down. The days get shorter and shorter, bird song diminishes to next to nothing, marmots are hibernating and the bears soon will be. Most of the wildflowers are done blooming, although a walk above the tram in the middle of the month revealed the last few flowers of six species. And the alpine zone is where we find our best fall colors: various shades of red on dwarf dogwood, avens, and lowbush blueberries, gold and russet on deer cabbage.

Nevertheless, on one day in mid-September, I enjoyed sightings of two kinds of critters that I don’t see very often.

Rusty-Blackbirds-by-bob-armstrong
Photo by Bob Armstrong

There were three rusty blackbirds on the shore of Mendenhall Lake, foraging over the wet sand and in the shallows. Rusties breed all across the boreal forest of North America and winter chiefly in the southeastern states. Even though Southeast Alaska is hardly on a direct route to the usual wintering area, I see them during the spring and fall migration seasons, sometimes by the ponds in the Dredge Lake area, occasionally elsewhere, but always in small numbers. Sadly, those numbers are likely to get even smaller: the number of rusty blackbirds has dropped dramatically in recent years, probably for several (undetermined) reasons.

Rusty blackbirds in Alaska often nest in wetlands and near ponds in dense, small black spruces, where nesting success is good, or in willow shrubs, with less success. Unlike their marsh-nesting relatives (such as red-winged blackbirds), they are usually monogamous. But similar to the other blackbirds, females do the tasks of incubating eggs and brooding young chicks. Blackbird males pitch in to help feed the chicks (but polygamous males commonly help mostly at the nest of a primary female; secondary females get less help).

In the nesting season, rusty blackbirds feed mostly on aquatic insects, including dragon and damselflies. During the rest of the year, the diet also includes seeds of many kinds and fruit. I was fascinated to learn that rusties sometimes kill and eat other birds.

The other critter I don’t see very often was Milbert’s tortoiseshell, a beautiful butterfly whose deep brown wings are banded with orange and yellow and adorned with red spots on the leading edge. All the color is on the dorsal surface, visible when the wings are spread. The ventral surface of the wings, visible on the folded wings, is more camouflaged, looking perhaps like dead leaves or bark. The one I saw was foraging on yarrow flowers—the only flower still in bloom in that area.

This butterfly overwinters as an adult, tucking into crevices in houses or trees, and emerging again in early spring. Batches of eggs are laid on nettles, which are the chief food of the caterpillars. (We could use more of them on the lower reaches of the Granite Basin trail!) Young caterpillars often forage in groups, but older ones are more solitary. They pupate in a folded leaf. When they metamorphose to the adult stage, they forage on nectar of many flowers, as well as sap and rotting fruit. In parts of North America, there may be two broods of caterpillars each year, but I doubt that there is more than one per year in Alaska. The one I saw was surely getting ready to hibernate, filling up the tanks, as it were, to last through the winter.

Addendum: As I strolled down to the beach below the pavilion near the visitor center, I stopped to watch the bear called Nicky and her little cubs. They trotted along the lowest pond on Steep Creek, where a few coho were jumping, waiting for enough water to allow them to ascend the creek. I don’t get to see Nicky very often either, so this was a happy sighting. The cubs looked pretty healthy but still very small…they will need their mom to catch some of those coho, so they can get fat enough to last the winter. But even Nicky, an expert fisher, can’t catch very many until there is enough rain to raise the water levels so the fish can get up into the stream itself. I have to hope for rain!

Beavers

the many benefits of an underappreciated mammal

beaver-towing-branch-jos
Photo by Jos Bakker

North American beavers were very nearly exterminated from the entire continent by European trappers and settlers. The near-absence of beavers for over 200 years changed the face of the landscape dramatically, not necessarily for the better. As humans took over the landscape and modified it to suit their real or imagined needs, they generally treated the few remaining beavers as intruders into the human domain, to be eliminated one way or another. That attitude still prevails.

To give local examples from my experience: one fellow said he hated beavers because one beaver chewed on a tree in his yard (serious profiling! Not politically correct). And a woman shrieked maledictions upon me, saying that beavers should be killed because they kill trees. DOT worries if pond levels rise along a roadbed or under-road culverts are clogged. Walkers complain if trails are flooded. And so it goes. For some reason, the usual first level of response is KILL them!

But although beavers so often get a bad rap, they are not all bad. In fact, they do some very good work. For instance, in the western Lower Forty-eight states, their dams help reduce erosion, trap sediments, control floods, and raise the water table, resulting in better grazing for ranchers’ herds and better stream quality for fish. Recognizing this, agencies and ranchers have begun to re-introduce beavers in some areas, to the benefit of humans, as well as fish and wildlife.

People often assume that beaver dams block salmon from coming in to spawn, to the detriment of our fish runs. However, adult coho and sockeye can usually jump or slither over most small beaver dams, if there is enough water below the dam to let them gather momentum. Furthermore, the adults are fully capable of waiting for days and days, until rains raise the water levels enough for easy upstream passage. So the common assumption of blockage is often just that—an untested assumption.

Furthermore, scientific research has shown that the ponds formed by beaver dams are superb habitats for juvenile sockeye and coho salmon: they grow bigger and faster there than in other possible sites, so they go to sea in better shape and survive better, and therefore more of them can return as spawners. In fact, in many cases, the size of a run is limited by the amount of suitable rearing habitat for juveniles and juvenile survival. For this reason, fisheries biologists in the Pacific Northwest have reintroduced beavers to some stream drainages, to help restore the waning salmon runs.

Ecologists also observe that beaver ponds are good habitat for nesting ducks, some shorebirds and songbirds, moose, and amphibians. Migrating swans and geese use them regularly. Standing dead trees are used by woodpeckers, chickadees, and certain species of duck. All this research and observation strongly suggest that we humans should take a less simplistic, more multi-factorial approach to beavers and their activities, in fact, an ecosystem-level approach.

Land managers in agencies and private concerns are learning that it is often possible to manage the effects of beaver activity rather than reflexively killing the beavers. There are now beaver-management specialists who offer solutions to many perceived problems—finding ways to keep the benefits of beavers while ameliorating or eliminating the problems. Among the techniques they use are devices known as pond levelers of several designs, diversion dams, exclusion fences of various sorts, baffles to prevent culvert clogging, step pools to facilitate fish passage. Trails can be raised or re-routed. Sometimes all that is needed is making and maintaining notches in dams for water and fish passage while lowering water levels somewhat.

In short, it is often possible to balance the ‘bad’ with the good and find a win-win solution.

 

Early fall in Cowee Meadows

burying beetles, sweetgale ecology, and dragonfly sex

A trip to Cowee Meadows usually provides a curious naturalist with something to contemplate. It’s also a good idea to keep an eye out for large, brown, sometimes temperamental, mammals with claws or hooves.

A stroll out there in mid-August discovered several things of interest.

A desiccated toad carcass lay in the trail, cause of death unknown. The body was attended by two big, orange and black, sexton beetles, maybe just looking for a meaty snack but possibly foraging for a carcass on which to rear a brood of larvae. Sexton beetles are also called burying beetles; they bury the bodies of small mammals and birds (or chunks of dead salmon), denuding them of fur and feathers, which are used to line a chamber housing the carcass. Eggs are laid near the buried carcass and the larvae crawl into the food-filled chamber. Unusual among insects, both parents feed the larvae on liquefied, partially digested meat, as the larvae also feed for themselves on the stored carcass. The number of larvae feeding on a carcass may be regulated by parental infanticide; if there are too many for the available food pile, the parents reportedly reduce the numbers. If for some reason, a female beetle does not have an active partner, she can raise a brood by herself, fertilizing her eggs with stored sperm. In this case, the question in my head was whether or not a desiccated toad would make good larval meals.

The low wetland before the beach berm is thronged with aromatic sweetgale shrubs. They harbor symbiotic bacteria in the root system; the bacteria take atmospheric nitrogen and ‘fix’ it into a form that plants can use. This species usually (but not always) has male and female flowers on different individuals. Male plants have already set their flower buds for next year, while female plants bear cone-like structures with small one-seeds fruits attached to the core. Some small critter had feasted on the seeds of a few plants, leaving the cone-core and fragments in a heap. A fat green caterpillar grazed steadily along the edge of one leaf, not deterred by the reported insect-repellent properties of this species. I was interested to find out that two field guides and two tomes on the flora of Alaska do not instruct a field naturalist how to tell male from female flowers—but the Trees and Shrubs of Alaska by Viereck and Little does!

Out on the beach, it was time for tea and snacks on a favorite log. The tide was low, and far out on a distant rock there was a black lump, which turned out to be an oystercatcher, able to loaf now that the chicks have been raised.

Instead of hobbling over the cobbles around the point, the return trip came back through the grassy/sedgey meadow, where the trails of trampled vegetation left by wandering horses made easy walking in most places. Sparrows popped up out of the tall grass and quickly dove back into the next dense cover. Closer to the river, the vegetation is shorter and marsh felwort flowers began to show up, not only on gravelly soils (as the books say) but also in deep black muck.

The old trail next to the beaver pond has been abandoned, but the water level was very low; there was not even any water in the stream below the dam that makes the pond. That encouraged a little exploration at the edge of the wet meadow along the old trail, which was apparently built (or rebuilt?) without consideration of beaver activity. In recent years, beavers had raised the pond level so the trail was often flooded well over ankle-deep; water was often trapped between the log rails on the trail margins. Rows of young alders have now sprouted up along the edges of that trail, making most of it rather impassible. But the low water level made it quite easy to tromp through the sedges on a parallel route. The newer, improved trail along the hillside would still be the trail of choice most of the time.

Near the beaver pond, dragonflies zipped to and fro, some of them in copula. Male dragons (and damselflies) chase whatever female flies by. If a female is not interested, she may evade the male by running away or hiding; in some species she just plays dead! A successful male grabs a female behind her head with claspers at the end of his abdomen, and they may fly in tandem for a while. The female, if willing, bends her body under his to bring her genitalia (near the end of her abdomen) next to where he has previously stored his sperm in the anterior part of his abdomen, so sperm can be transferred. Copulating dragons make a circle or ‘wheel’ of their bodies. If the female had mated previously, the present male may try to scrape out the sperm of the first male; the ‘opinion’ of the female with respect to this action apparently has not been recorded.

Northern-Bluets-mating-by-bob-armstrong
Photo by Bob Armstrong

Some days later, I watched a pair of bluet damselflies in tandem, perched on a sedge blade in a mid-elevation muskeg pond. The female bent her body up to touch his, in the copulatory position, several times, but they did not form the mating wheel. Three other bluet males patrolled this pond, sometimes zooming in closely on the pair, and even contacting them, as if to try to steal the female away. This is a behavior I’d not seen before. At the edge of the pond lay a dead female, possibly drowned in the act of laying her eggs in underwater vegetation. Some bluets lay eggs in vegetation near or on the surface, but some species of bluet actually submerge the whole body while egg-laying, and upon occasion need to be pulled out by their partner or perhaps by a nearby unmated male.