November 15, 2014
October 18, 2014
The natural world is ripe with imitation. It is the ultimate form of flattery (and self-preservation) to look like something else – especially if that something else is inedible. Take a dry leaf, for example. Only a low life decomposer would even consider a dead leaf as food, so many insects wear a dead leaf costume in order to convince hungry predators to overlook them. Moths are especially prone to this disguise tactic because the structure of their wings lends itself well to such fakery.
On a day when brown windblown leaves were tousling about, I spotted this Geometer Moth clinging to the rough bark of a Red Maple. The adult form of twig-imitating “inchworms,” geometer moths extend this youthful deception to become grown up leaves.
It might seem that such a disguise fails when it is exposed against the dark background of a tree trunk. After all, I spotted the thing from a dozen feet away. But, then again, it had such a good leaf look that I doubt that even a savvy predator would discern this from the millions of other leaves blowing about. This individual had the additional effects of age to enhance its outfit. Multiple tears – not part of the original wing design – gave it the truly authentic worn look of a crackled October leaf.
Because the tears are not genetic parts of the camouflage look, this moth will not pass on these traits to the next generation. Probably the result of a short life of heavy use, they will likely insure that this critter will survive its full short life before succumbing to a natural death from the chills of autumn.
October 13, 2014
Much of the life of Funnel Weaver Spiders involves a waiting game. Instead of pursuing prey like wolf spiders or animated jumping spiders, they spin flat sheet webs and wait for insect prey to walk across the surface. The killer waits inside a special side chamber (the “funnel”) until signaled to emerge by the vibrations generated from tiny feet crossing the web. A quick dash, followed by a fatal bite secures the prey and renders it a meal. When the mating urge is felt, the males abandon their web and go courting – fully realizing in their instinctive little brains that this risky behavior is necessary for the propagation of the species. Ah, the things they will do for love.
Female Funnel Weaver spiders wait within their liars until prospective mates come a knocking. For a male of the species this is a tricky prospect because knocking at any funnel weaver’s door is tantamount to inviting yourself for dinner – as in YOU being the dinner. When that doorway frames a hungry female, about a third larger than you, the danger is even greater. Although no self-respecting spider would admit it, the empty carcasses of dead insects lining the path certainly don’t inspire confidence. So, before he can get down to business, the suitor must convince the female that he is not a meal but a mate.
He will dance about and wave his legs to signal manly intentions. Pedipalps – specialized male appendages to either side of the jaws – are moved to and fro like an airline worker guiding a landed jet to its gate. All this is intended to convince the potential Mrs. that he is a virile eight-legger and not a six-legged juice box. Once convinced, the female will allow her suitor to advance and begin his masculine task. To say the least spider foreplay is a creepy affair, but that which follows is fascinatingly boring.
I witnessed this drama taking place in my yard last week. A sizable female weaver (see first photo), who had maintained a funnel bridging the gap between an old barrel hoop and the siding of the house, received a late afternoon visitor. He ably subdued her into taking a passive legs-up pose but never let his guard down during the process which followed. While still slowly waving one of his pedipalps in the air he carefully engaged the other on her tender undersides.
The tips of the pedipalps are saucerlike with the inner surface of each sporting a black coiled organ called an embolus. They are maneuvered down to the female’s genital opening and the tip of the embolus inserted within. Then, the male pumps his semen into the female .To carry the airline analogy one step further, this process is more like fueling a jet and just about as exciting. One big difference here is that the process takes many hours (six hours or more in some cases!). And that, my dear readers, is not a spectator sport. I left to watch some corn growing across the road.
The male made his escape by nightfall (at least he was gone by the time I checked back much later). He will live to inseminate several more females before dying with a smile on his eight-eyed face. Females will also mate with several more males if they are given the opportunity. In the case of my yard spider, she retreated to the space under the siding and never appeared again. This could have been her third suitor for all I know. Unseen under the shingle, she would have laid several lens-shaped egg sacs containing 50-200 eggs which will pass the winter.
When the young emerge in the spring they will likely scamper over the desiccated remains of their mother who died peacefully in place after laying her eggs. There is much creepiness in the spider world but then again it is all about perspective isn’t it?
September 15, 2014
Second nature: something that should be natural and easy to do –such as a short piece on a small subject based upon a few moments of nature observation. Get it? Second, as in part of a minute, and…never mind.
You may recall my blog from a couple of installments ago in which I told the riveting details of my encounter with a Leafy Spurge Sphinx (a new species in Michigan). O.K., so it wasn’t riveting – I merely picked the thing up as it was crossing a Northern Michigan road. The only riveting part was when a truck nearly ran it over before I could nab it. At the time of writing I mentioned that I would await the coming pupal stage of this beast as the next point of interest in this story. Well, he has finally “taken the plunge” and I am duty-bound to bring you up to date.
Safe within the confines of its high-tech enclosure (a coffee cup partially filled with sandy soil) the caterpillar shed his colorful skin and converted to an intricately patterned pupa. It tunneled down about an inch and created a chamber whose walls were held together with a loose mat of silk before performing the transformation.
The pupa retains the caterpillar’s horn and spiracles (breathing holes), but otherwise displays – via outlines on the exterior of the casing – the new look it will have as a sleek adult. Large compound eyes sit opposite on a well-defined head. A long tongue has replaced the chewing mouthparts. Destined for sipping nectar from tubular flowers, the tongue appears down the center along with the two linear antennae. Both are framed between the leading edges of the folded mini-wings. The sixteen legs of youth have been reduced to six and they are neatly aligned with the tongue and antennae.
Inside this simple casing a remarkable transformation is occurring. The muscles of old are dissolved and re-created to serve powerful wings, tongue, and legs. Evidence that the abdominal muscles are already functioning, the creature wiggles freely when handled. This, of course, makes for riveting footage (see here) but we’ll have to wait until next spring before the final exciting chapter in this metamorphosis takes place. This thing is more moth now than caterpillar – straight and peaceful (unlike Darth Vader).
On the subject of non-caterpillars, Dogwood Sawfly larvae (see above) are chewing away at the refugee Gray Dogwood sapling next to my house. Although they look very caterpillar-like they are very not (odd wording, I know, but I’m sticking with it). Sawflies are closely related to bees and wasps and the adult stages bear this out. The larvae are plant eaters that live and eat like caterpillars and therefore have adapted like traits and appearances. There are a few distinctions that separate them from moth/butterfly (let’s call them lepidopteron) larvae, however.
Sawfly larvae have a solid head capsule with two prominent eyes, whereas lepidopterans typically have three sets of tiny eyes and a divided head capsule. The leps have only four sets of fleshy legs in the center of their body and the sawflies have six or more pair. Even though some caterpillars are colonial, Sawflies are always colony feeders so you rarely find just one.
Members of the family have the unusual habit of raising their hind ends when disturbed – as if to say “my butt to you.” The Dogwood sawflies take this to such an extreme that they actually curl up like miniature cinnamon rolls. Younger stages of this species, such as these examples, are covered with a waxy down.
These little fellows will lose that downiness and take on a smooth stark black and yellow skin as they approach their last stage of larvalhood. Like the sphinx moth they will burrow under the ground and overwinter as a pupa. Both the Spurge Sphinx and Dogwood Saw Fly will spend the winter as un-caterpillars: one as a “never was” and the other as a “used-to-be”.
August 17, 2014
I’m pretty sure that women don’t like the phrase “honey-do” list. It universally implies a litany of “bothersome” husband oriented tasks, assigned by an “overbearing” wife, nearly always involving tools, sweat, and “easy” weekend projects such as replacing a patio and building a new one. I am not here to argue the merits of this phrase, or lack-of same, because I am one of those husband type people looking at his 35th…er, 36th year of marriage and would like to celebrate our 37th. No, I am here to present another type of honey-do list which is performed exclusively by, and pretty much only for, females. There are no delicate issues to dance around on this one. I’m talking about aphid farming, ya’ll.
Many species of ant engage in livestock farming. The activity is performed exclusively by the female workers for the purpose of maintaining and harvesting Honey Dew for what is basically an all female colony (the male drones only enter the scene later). The gang of black ants living in my…excuse me, our (sorry honey) yard at Dollar Lake are so engaged in this pastoral pursuit. Their pasture consists of a small bushy Balm of Gilead tree about ten feet from their door and about 50 feet from ours.
The cattle in this farm setting are aphids, aka plant lice. These sucking insects feed on the sugary plant sap. Because this fluid is low in essential Nitrogen, they must consume a whole lot of it in order to gain the essential amount of this chemical. This means that much of the sugar is excreted as waste – aka sweet pee or honey dew.
The sweet-loving ants harvest this crop in the manner of a dairy farmer milking his/her herd, although the details differ. Individuals will approach the hinder end of a fat little plant louse and tap it with their antennae. The aphid is thus prompted to produce a juicy bead of honey dew in response. This nectar the ant eagerly drinks and eventually transfers to other ants in the colony.
The ants are, for lack of a better name, Black Ants. I must resort to this generic description because I do not know the exact species. Of course I did not name the aphid species, but no one seems to care about that. Unfortunately, most folks don’t ask about ant types either. This is not a good thing, but I must not be hypocritical here. Except for Carpenter ants, Wood ants, and Auntie Em, my knowledge of ant species has remained fixed since a child. Back then there were only two ants in the world; black ants and red ants. One fought the other and that was that. Given that there are well over 12,000 species of ants in the world I suppose I could be forgiven for passing over this part of the discussion for the sake of the presenting the bigger picture.
This basic aphid/ant interaction certainly benefits the ants. At times it may seem like a one-sided interaction because a few of the aphids occasionally serve as meals on wheels. Just like human dairy farmers who regularly send some of their animals to slaughter, ant farmers eat a few of their aphid charges from time to time. The aphid colony, in spite of these occasional individual sacrifices, do ultimately benefit from this arrangement. Beyond performing the obvious waste disposal service (preventing fungus formation in certain cases) the ants serve as shepherds. They vigorously protect their precious aphids from wandering predators such as ladybug larvae and wasps. In other words, more aphids survive under antcare than without. Since both sides benefit, this type of plus-plus interaction is called mutualism (or symbiosis if you prefer).
I stand on the shoulders of others – or under their feet – when it comes to explaining the realities of aphid farming. I can claim little more than observing big insects surrounding clusters of tiny weak ones. Researchers have spent long hours investigating this phenomenon. One of the more fascinating aspects, involving the use of chemicals agents, was investigated by a team from Imperial College London, Royal Holloway University, and the University of Reading. Not only do some ants keep their charges in line by physically moving and herding aphids, but they also lay down chemicals with their feet that act as invisible fences. Aphids attempting to cross over these chemical fences were observed to significantly slow down as if they were treading on fly paper. There is also some evidence that other “semiochemicals” exuded by the ants prevent mature aphids from sprouting wings and flying away (which is how aphid colonies spread).
Such a complex interaction, taking place but a few yards from my door, is worthy of much more discussion but I must end it for now. You see I have a few honeyd….er, things that I must attend to.
August 3, 2014
It is easy to imagine the inner working of a squirrel’s mind. They can be excused for being continually distracted because nuts must certainly dominate their thinking. Why else would they stop in the middle of a street in the midst of heavy traffic? “Nuts, cars, danger, nuts, nuts, nuts, cars, nuts…” is not a healthy thought pattern (and one that usually ends tragically after the fourth “nut.”).
It is unfair, of course, to pursue this line of reasoning. Squirrels are multidimensional being – not as fascinating and deep as wolves or chimpanzees perhaps, but complicated in their own way. They are not all about nuts and would likely go nuts eating nothing but nuts. During the summer, when nuts are scarce, they become fungal connoisseurs and actively seek mushrooms.
Given that many of the top chefs in the world are fungal connoisseurs and are well respected for it, our bushy-tailed rodent friends are certainly worthy of elevated human perception. I wonder how many great chefs have been hit by cars when pondering culinary thoughts and ignoring traffic? This would be worth investigating. But I diverge.
The mushrooming skills exhibited by the local Grey Squirrels are something to behold. They eagerly devour any ‘shroom that dares to poke its gilled head above the ground and, I must say, look refreshed while doing it. I wouldn’t dare suggest that mushrooms often have a nutty taste lest any nearby squirrel goes postal at the mere mention of the word “nut” (at least in the month of July and August).
I am unwilling to taste the mushrooms that the Greys are currently harvesting in my yard. I therefore will not have to put myself in the position of declaring their nut-like taste. By general appearance they seem to be members of the Russula family. This large fungal group runs the gamut from being highly edible to bland to poisonous in terms of human consumption. The mushrooms in this squirrel discussion are gilled and have large reddish caps, easily crumbled, which are somewhat turned up at the edges on larger specimens. These caps are sticky and shiny when wet and often have pine needles or detritus sticking to them. Overall, this description matches that of the Blackish-Red Russulas (by the way, this is their actual species name and not one I just made up). It’s probably not worth mentioning, but this species is not poisonous but relatively inedible due to its “acrid taste.”
Our taste is has nothing to do with squirrel taste. Oddly enough, squirrels have no aversion to poisonous mushrooms so this is a moot point when it comes to edibility. One species of Russula, the Emetic Russula, is quite poisonous to humans but is eagerly eaten by Red Squirrels without effect (well, other than leaving them with a sense of satisfaction).
There are several color varieties of mushroom-eating Grey Squirrels about. All are the same species, but several are black and one is a “normal” reddish brown grey squirrel (or is it a blackish-red grey squirrel?). There is no particular modus operandi when attacking mushrooms, although they seem to go for the caps. One of them hung upside-down while devouring his prize while yet another served it up on the ground. It held the outer edge of the cap like a wheel and took bites out of the rim as it rotated. Sometimes they will simply take a few bites out of a standing mushroom and leave it in place.
I’m not sure why, but these fellows never seem to finish a whole mushroom. Often they’ll drop one, half consumed, and then move on to other things. I suppose it could be due to a mental distraction – perhaps feeling the sudden urge to cross a road or stopping to check the status of the ripening crop of nuts, but I’ll give them the benefit of the doubt. It is probably due to the sheer abundance of the fungal treats and is equivalent to an overindulgent child leaving the pizza crust.
May 31, 2014
In nature, things are always changing- beaver ponds to meadows, meadows to forests, Hanna Montana deteriorates into Miley Cyrus etc. Nothing really remains the same. Even sturgeons, those timeless bastions of bottom feeding, change individual form as they grow from fry to formidable fish. They also, like all organisms, go through daily and monthly changes depending on seasonal and courtship needs etc. In short, nature is a dynamic and not a static entity.
Much of the joy of nature watching revolves around observing both long term and seasonal changes. Of these two, however, seasonal changes are the most accessible for the curious naturalist (“phenology” for those of you working on a crossword puzzle). Birders are keen to minute plumage changes and some of them can get in an exhaustive description of a 2nd year Herring Gull before their first sip of Green Tea in the morning. Green Thumbers are all about growing seasons. A Brown Thumber, such as myself, is fully capable of sucking the joy out of a simple seasonal observation by encumbering the reader with extraneous details. It is time for me to do so again.
Let’s take Cedar Apple Rust and Red Squirrels as two examples to illustrate “The Pageant –pageant- pageant Of-of-of Nature-nature-nature” (he says with a booming echo-chamber voice). These two are rarely mentioned in the same sentence but both organisms share a reddish coloration and a period of dramatic change over the past month.
I took a look at the Cedar Apple Rust gall in a previous blog and won’t rehash the topic except to bring us up to snuff. The gall, a hard meteorite-like growth with multiple “eyes”, is found on the branches of Red Cedar trees. It is the alternate stage of a type of apple rust called Cedar Hawthorn Rust which spends one year on the leaves of hawthorn trees and next few years as a gall on Red Cedar. It takes several years for the cedar galls to mature and during this time they remain relatively dormant. I left off with this stage in my previously mentioned blog with a promise that I’d come back when they explode. This spring, true to my word, I returned to witness this wonderfully odd transformation.
The Spring rains incite these galls to exude long gelatinous “horns” in the manner of a Chia Pet from Hell. These structures, called telial horns, bear millions of tiny two-celled spores which float off into the air to infect Hawthorn Trees. Over the course of the spring season, the galls and their crop of snot horns dry up and re-swell with each passing weather system – releasing a new crop of spores each time.
Each cedar gall is good for up to 10 releases before being tapped out. Because the cycle plays out again and again every year, you can catch the annual show if you time your visits properly. As in all cycles there are good years and bad years (which gives some hope that Miley Cyrus will outgrow her fungal stage and return to dormancy).
The spring transformation of the Red Squirrel is far less dramatic than the Cedar –Cyrus thing. As mammals these expresso charged little rodents run through an annual molt cycle. They undergo a fall and spring do-over. Again, I have addressed this before but I was so amazed at the sudden visible change in one of my Dollar Lake squirrel that I feel compelled to share it (and, of course, explain it until it is no longer fun).
Red Squirrels undergo a spring and a fall molt. The two occur in opposite directions. The fall molt goes basically from back to front while the spring molt goes front to back. A good way to remember this is to reverse the normal phrasing we use for remembering time changes thus: “Spring back, Fall forward.” Remember this for it will serve you well in later life. This might be one of the qualifying questions asked by St. Peter when you ascend to the pearly gates.
Molting is a gradual process and hard to notice when in progress. It varies between individuals, but most Red Squirrels start spring molt by mid-April and complete it by June. Some individuals have yet to molt (as this backyard Red still in winter coat as of the last week of May). A comparison of the two pictures of my notch-eared friend, taken one month apart, will tell most of the story regarding the Spring molt. The first shot, taken in late April, shows the first stages and the second, snapped in late May, reveals a fully summarized squirrel.
You’ll notice in the first shot that the squirrel was still primarily in winter coat with grayish brown sides, a reddish back stripe and tail, ear tufts, and a dirty white belly. There was only a hint of a dark side stripe. A closer look, however, shows that this animal was already in molt. The face and eye ring are already garbed in short hair while a fuzzy top knot of winter hair remains.
By the time I took the second shot, the process was complete. The animal was covered with short reddish hairs with a clear black side stripe bordering a bright white belly. This is a portrait of a summer squirrel.
We missed the intermediate stages of the molt, but I can tell you what happened. The change began on the nose, chin, and feet. The process is so consistent that it began on the front feet and on the inner edge of the hind feet. The sides of the head go before the top and the rest continues along the sides and back until ending at the rump (a natural ending for sure). Somewhere along the way the ears tufts are dropped.
So there you have it. A squirrel and a spore ball can give us a small insight into a massive world of natural change. I guarantee neither subject would have been brought up in polite conversation until now. It is your duty to carry the ball and tell them something that they don’t really want to know.
May 21, 2014
A miniature forest of pale straws has taken over the near lake portion of my Dollar Lake property. Although rising several inches above the grass they are not obvious except in the low rays of the morning sun. It is appropriate that they are at their visual best in the “Dawn Time” because these plants, called Horsetails, are literally from the Dawn Times of earth history.
Although they may be small now, Horsetails come from a giant past. Perhaps the term “living fossil” is often overused (especially in reference to ancient aunts or family patriarchs) but these plants have been around for at least 300 million years and certainly qualify. In comparison, the dinosaurs are newbies and wannabes – having appeared and flamed out as the horsetails stood by and watched with unblinking stares.
The first members of this group attained tree stature at a time before trees were even a twinkle in evolution’s eye during the Carboniferous Period. These swamp plants shaded the first amphibians and provided perches for giant dragonflies. One early type, called Calamites, grew well over 60 feet in height on hefty trunks nearly two feet in diameter. Fossil imprints, such as the one I am holding in the photo below) record a plant that, except in scale, is identical with its modern descendants.
There are many different species of horsetail and all share “horstaily “features such as jointed ribbed stems and spore reproduction (none of this new-fangled flowering stuff). The plants grow via underground rhizomes which send up two different types of stems – fertile and non-fertile. And you thought I was going to say big ones and little ones, didn’t you!
Non-fertile stems are green and most produce whorls of strappy leaves (which just happen to make them look like horsetails, by the way). A detailed look at these stems will reveal rows of white silcates which give it a tough exterior and creates an abrasive quality useful for scouring out pots and pans (thus the common pioneer name of scouring rush).
Technically, it may be best to call my ancient little plants by their formal name of Equisetum arvense but let’s be civil about it and stick to Field Horsetail. My miniature crop consisted of early spring fertile stems only. These shoots are ghostly pale due to their lack of chlorophyll. Their only function is to produce a spore-bearing cone and then wither away. They rarely last more than a week.
The cones, or strobiles if you prefer-bile, themselves are made up of multiple scales which look like up-side down flowers – complete with petals. Tiny spores are produced by this structure and they drift off with each passing wind gust.
I teased several of my horsetails into releasing spore clouds and counted as many spores as I could. I reached 125 before….well, actually, no I didn’t. That was a shameless lie just to keep your attention long enough to tell you that you can’t see the individual spores with the naked eye. Under the magnification of a high power lens or scanning microscope, however, they take on a very interesting form.
Each spore is tightly wrapped with four elaters or tendrils upon release. Moisture sensitive, they un-furl like springs which aide in the spore’s motion. The enlarged foot pads at the end of each tendril give the whole thing a strangely alien appearance. One thinks of those alien invaders from “War of the Worlds.”
These horsetail spores are, of course, the exact opposite of alien forms because they have been an original part of our planet’s life for a very very – did I say very? – long time. We are alien forms by comparison.
May 15, 2014
I did several versions of a Chipmunk for my daughter’s baby shower invitation and it took a while to decide on the final version. She insisted on a woodland theme for the arrival of this child (and when pregnant women insist on something it is smart to comply). This theme will continue into the decor of the baby’s room and might even extend to the child itself. Who knows, he might be raised as a small woodland animal. If she and her husband start calling the baby’s room a “den” or “burrow” then there will be cause for some alarm. As a career naturalist who raised his children in the “woodland ways” I just may be seeing my chickens come home to roost.
At any rate, the issue of the invitation, the cake, and the room decoration for the shower revolves around a nature/woody theme. As invitation master (a self-applied title) it was my duty to come up with an appropriate woody type product upon which the bare realities of “when”, “where”, and “for who” will be draped. It was not as easy as I had hoped.
Apart from the fact this was for a pregnant female – an entity pickier than even the biggest of corporate bosses – it also had to pass my muster. The primary issue was finding the right woodland creature and this demanded some research and inspiration. As you can see, I am not a “clip art” kind of guy.
My wife and I opened up our tiny Dollar Lake cabin a few weeks ago. In that cozy woodland setting I figured there would be plenty of inspiration, and there was. Critters paraded by, as if on review, and vied for the cutest title. A curious Painted Turtle bobbed to the surface close to the dock, a beautiful pair of Ring-necked Ducks landed for a visit, and a busy Phoebe darted about for insects. All of these critters, while fascinating, are not really “cute” in the pregnant sort of way. Two of them don’t even fit the woodland theme at all. I could make an appealing little Phoebe character but the grayness of such a bird rules it out. Sorry Phoebe, maybe next time when the shower theme is insect-eating birds.
I have a love/hate relationship with squirrels and there are plenty running around my home yard to provide ample opportunity for consideration. At Dollar Lake, however, the squirrels came in all shape and manner of being, so they had to be reviewed for their fuzziness factor. The black Gray Squirrel was just plain creepy and the Fox Squirrel just plain too fat. The Red Squirrel put in a very good appearance. I am partial to Reds, as you may know regarding my home yard squirrels, but this one was a stranger to me (and I to him).
Perched in the White Oak over the shed, he displayed unusual patience when approached. A battle scarred veteran with a torn ear, he was appealing none the less. But, it was the resident Chipmunk that finally caught my eye. He ultimately won his place as the feature creature on the invitation.
Cheeks fill with acorns he dashed to and from the shed. At one point he piled through the dry leaves and popped up with a prize nut which demanded immediate attention. He flittered up to the old pine stump by my porch and dismembered the acorn with great skill. Then he was off as if blown by a gust of wind.
The first cartoon version of this creature was cute enough – in fact it even passed inspection from the queen bee right away. I pictured a perky Chipper, cheeks chock full of nuts, and obviously very happy with his situation (in other words with lots of “gifts” lying about in the form of acorns). As art is was fine.
Unfortunately I was unsatisfied. It was cute but not “chippy” enough. Looking back at my photos of the cabin Chipmunk I was struck by the fact that these critters have very prominent noses. My first artistic chipmunk had a mere suggestion of a nose. No, my next effort needed an enlarged honker in order to pass my naturalist muster.
So, I re-did the thing and came up with Chipper no. 2. I was much happier with this version because it was a cartoon which was true to the animal depicted and, most importantly, it also received approval from the daughter. The invitations, complete with the honkier chipmunk, went out this week without further alteration.
I plan on releasing a live chipmunk at the shower. I’m sure the ladies, my woodland daughter, and future grandchild, will appreciate how animated an actual woodland creature can be in a confined space!
May 10, 2014
The crayfish towers in my backyard grow faster and higher than the crabgrass, cress, and dandelions do. (I also have some actual grass in my yard but that’s hardly worth mentioning). Each spring, the Burrowing Crayfish (aka Devil Crayfish) pile up dozens of lofty mud turrets. Some, reaching 8 inches in height, cast long dark shadows over the evening lawn which rival those cast by the local mole hills.
The first diggings literally pop up overnight and gain stature over the course of a week or so. They tunnel deep into wet substrate and deposit the excavated soil/mud around one of the opening at the surface. Other entrances are left un-turreted and open flush with the surface. Eventually they complete their work and plug the tower entrances – apparently coming and going via their “naked” entrances.
They are allowed to build their noble chimneys without obstruction because my yard is very wet and the water table is only a foot or so below level surface. A spring stroll across the yard is like walking on a sponge. I don’t get a chance to start mowing until well after the “normal” season for such activity has commenced (at least according to my neighbors who start mowing as soon as the snow is less than 1 inch in depth). In other words, I don’t get an opportunity to knock these towers down – not that I want to – until well into May.
Burrowing Crayfish work and feed under the cover of night so their new construction efforts aren’t revealed until the rising sun of morning. These creatures, although very common, are rarely seen. Last week I took it upon myself to catch one of these clawed arthropods “in the act” and capture it on film…er, digital bits of imagery.
It is assumed that the chimneys are basically the result of excavation and don’t really serve a purpose. In other words, when the digging is done they are normally allowed to collapse on their own. But, it does appear that there is some instinctive need for these turrets early in the season. In other words -again – when they are done they are not really done and will be repaired at least until late spring.
My daughter’s dog accidentally knocked over one of the completed (plugged) towers a while ago. Her antics (the dog’s, not the daughter’s) completely exposed the burrow at ground level. The crayfish re-built much of the turret overnight. The fresh work was apparent as a ring of dark moist soil around the hole. So, I knocked another one of the finished chimneys over and planned on a nocturnal visit to watch the show.
Under the dim glow of a warm quarter moon I snuck across the squishy lawn using my tiny, but intense, Yoda keychain flashlight to illuminate the way. Sure enough, the little Devil was already at work as evidenced by glistening mud pellets piled up on one side. I waited patiently and was able to capture the beast as it returned multiple times with new material and tutored me in the art of chimney building.
The crayfish first appeared at the entrance as a very wet blob of grayish clay. Paired pincers, poking out from the blob, were the only indication that a creature was the impelling force behind the mud ball. In the manner of a bulldozer, the crayfish forced the material up and over the edge. The large pincers (called Chela, if you are a crossword person) are used to contain the sides of the blob while the first pair of legs apparently serve to take up the rear. The whole is retained by the creature’s “face” – leaving the turreted eyes free to search for danger. A few probing pats with the claws secured the mud into position.
Each surface visit was punctuated by an absence of a few minutes as the crayfish descended to the depths to excavate some more material. It was sensitive to my presence and any movement on my part would send it back down for a few seconds, although the camera flash didn’t seem to register any reaction.
On the following morning, I could see that the burrowing beast had completed a small wall around the burrow entrance. Based on what I saw, it would have completed this task within a few hours. I’m assuming the rest of the night was spent feeding and flushing the camera-flash stars out of his eyes. The chimney was sealed shut a couple of nights later. I’ll let this crayfish construction stand for a week or two more until I am able to fire up the mower.