Naturespeak A naturalist's view of the world

July 30, 2010

Gypsies, Tramps and Thieves

Filed under: Uncategorized — wykes @ 10:15 am

It is a sad that the first reference that comes to my mind when the word “Gypsy” pops up is that dismal Cher song “Gypsies, Tramps, and Thieves.”  I might need to remind you that the chorus went something like “…gypsies, tramps, and thieves that’s what the people of the town would call us….” and end with “but every night all the men would come around and lay their money down.” Ooh, what those steamy suggestive words wrought in the juvenile mind! Anyway, as much as I hate to admit it, this is the perfect lyric to accompany my discussion of Gypsy Moths. These moths are, you see, truly scandalous immigrants who move in and strip our forests of their leaves and turn our yards into bordellos. They give real Gypsies a bad name.

We can blame a Frenchman (ah, those French) named E. Leopold Trouvelot for bringing the initial bunch of Gypsies to Medford, Mass. as part of a silk moth experiment in the 1860’s. It was his desire to improve the breeding stock of native silk-producing moths by crossing them with European Gypsy moths. In 1869 an accidental release (due to storm damage I believe) introduced the creatures to the wild American landscape.

Although Trouvelot’s experiment was a failure, his moths successfully took hold in the hardwood forests of the eastern United States. The increasing automobile travel of the 1920’s spread the population westward and they are still on the move. Cyclic infestations have since resulted in the defoliation of an estimated 1 million acres per year. Perhaps we should call these things French Folly Moths – even though that would be unfair, but who cares. The French are not always fair (I am, of course, speaking of those European French and not my Quebecois cousins).

Last week, the North Country around our Dollar Lake cottage was full of Gypsy Moth activity. This was not a heavy infestation year – around West Branch anyway – so there weren’t a lot of caterpillars in evidence back in June and early July. The emerging adult moths (see above) were everywhere, however. In fact, the male moths were flitting about and “laying their money down” with reckless abandon.

Male Gypsy Moths are the first to emerge from their pupae. Equipped with huge feathery antennae (see here, above, and here) and strong flight muscles, they immediately begin seeking out the females. Unlike most moths they are day fliers. The females emit a stream of seductive perfume into the air called pheromone. This “come to momma” scent will travel for miles on the wings of a light breeze but it works best within a range of a few hundred feet. The males fly an erratic (erotic?) zig-zag pattern as they attempt to intercept a few molecules of this pheromone plume. Once detected, they will follow the scent “upstream” to the source and complete the deal.

Female Gypsy Moths (see beginning photo) look quite different from the brown athletic males. They are much larger and fatter, and possess white wings peppered with dark spots. Oddly enough, they cannot fly. Upon emergence, they simply crawl a few feet away from the pupal skin and begin sending out chemical invitations.

Soon after mating, the rotund female plasters an oval egg mass onto the surface of the tree or building where she emerged. Each mass, containing around 1,000 eggs, is covered over with a weather-resistant matte of fine orange body hairs. The hairs also act as a predator deterrent since they can be nettle-like in their effect.

As I write this blog, there is not an adult Gypsy moth to be seen from my porch. Last week there were dozens of them treading the breeze like so many salmon running upstream. All the adults die after their brief flight period and the local flight time has passed. Like their namesakes, they come and go. Only the egg masses now remain to overwinter. I will attempt to destroy as many of these as I can by next spring (while uttering blasphemous French phrases) but I know it is a fruitless endeavor. These French Follies will not easily retreat or surrender.

July 26, 2010

The Music of the Night

Filed under: Uncategorized — wykes @ 8:13 pm

One evening as the sun dipped behind the trio of white pines on the far side of Dollar Lake, a lone song sparrow let out a brief chortle before settling in for the evening at 9:30 pm. Just a few minutes before a gang of coyotes engaged in a spirited yipping session somewhere off in the distance beyond the lake. Their high barks echoed eerily through the trees. A single loon let out his plaintive call at exactly 10:05 pm before the crickets finally took over.

The bats began their flight at approximately 9:50 pm and concluded at 10:00 pm. Unlike the sparrow, loon, and frisky coyote pack, their part of the end-of-day show was basically a silent one– only an occasional click descended to human hearing level.  In actuality, however, theirs was the loudest contribution of all. The decibel range of an echolocating bat generally exceeds that of a typical rock concert. Because the screams are delivered in the ultrasonic range they fall as sounds of silence upon our human ears (if only Alice Cooper’s voice was ultrasonic!). With the help of a bat detector I was able to convert the silent scene into 10 minutes of sonic mayhem. The creatures employed an incredible variety of chirps, buzzes, and pulses before moving on into the night.

As on this first night, the bats arrived and departed like clockwork every night. Over the course of four evenings at the lake there was a tight ten minute period when they flitted about the maple trees just off the front porch and out over the still waters of the lake.  From our position sitting under the overhang, the ghostly forms were outlined against the pale blue sky only momentarily before they were swallowed back into the shadows.

There were 5 or 6 individuals -maybe more – but it was hard to keep track in the failing light. Unfortunately, I can’t tell you what kinds of bats were involved but I suspect they were Big Brown Bats (triple B’s for short). Their voice recordings were in the 39 kHz range which is smack dab in the BBB range. I did manage to capture one image after randomly firing off nearly forty shots into the night air (see below and detail here). As you can see, well………… it’s definitely a bat!

The resulting sound recordings were much clearer. Listen to these two tracts (No. 1) and (No. 2) and you’ll get a sense of the sound landscape surrounding a group of feeding bats. The first is a recording of the multiple beasts zipping about close to the porch and under the confined area of the trees. You’ll note that the clicks take on a crinkling or popcorn-like texture as they feel their way between the tree trunks. The second tract was recorded out over the open lake where there are no obstructions. The bursts are much louder and come much closer to the earlier rock concert analogy (the drum solo part). There are also fewer bats in this second recording – perhaps two at most.

It is hard to believe that all these sounds are made by simple larynx or tongue clicks. The resulting sonar waves are sent out to detect, locate, and eventually identify the potential prey around them. Returning sound waves, bouncing off of a flying insect, are picked up by the sensitive ears. Big Brown Bats are beetle specialists, but moths, midges and mosquitoes are also on their menu.

It is hard to tell exactly what is going on at any given time but there are moments within these “silent flights” in which the moment of prey capture is recorded. Listen again to the recordings and you’ll hear a series of ascending zipping sounds. As the bats close in on their quarry, their sonic pulses get closer together until finally ending at the source. The moth’s scream is silent. With a flip of the wing or tail membrane, the insect is gathered in and funneled to the open mouth. That zip is the sound of living bug zapper doing what it does best.

July 22, 2010

On Frogs and Their Nostrils

Filed under: Uncategorized — wykes @ 9:08 pm

Had I of titled this blog “On Green Frogs and their Manner of Calling” I would have instantly turned away those of you who are looking for light summer reading. It would have sounded far too scientific and, well, far too boring for a good beach read.  Now, the subject of frog nostrils is much more intriguing. The mere fact that frogs have nostrils might be shocking enough to prompt the reader to continue on. O.K., so it’s not that intriguing. I take it that anyone reading this blog is not looking for a light summer read but a deep fascinating insightful look into the world of nature and how she works. What better way to do so than to delve deep into a frog’s nose. O.K., so that’s not true either. So what of it? The frog and his nose is the subject that needs exploring – even if it is in a shallow and superficial way.

The shallows rimming the edge of Dollar Lake are choked with all manner of submerged aquatic plants and floating lilies. Towards dusk, these places begin to resound with the clucking calls of the resident male Green Frogs. The silent sunset scene pictured above lacks the necessary amphibian sound track. These large frogs, second in size only to the portly Bullfrogs, can put out a hefty burp of a call but it fails to carry far. It is has a hollow quality that dissipates like a smoke ring. The calls are random and widely spaced, so they never become irritating to the human ear. I’m sure they are music to the feminine Greens, however.

One especially talkative fellow was located a few feet from my dock and I was prompted to watch him with great interest. Normally watching a stoic green frog is like watching paint dry since they will remain motionless for hours at a time. This one was in a calling mode and performed his task while floating half-submerged on the surface.  His sequence was basically the same each time. The first noise out was the trademark “plunk” – a sound likened to plucking a loose banjo string. This was followed by a series of rolling “bulla-rup bulla-rup” vocalizations terminated by a final terse “tuck”. The last note had the quality of knocking on wood. Watch the video here and you’ll see and hear what I mean (note the competing notes of another green frog nearby).

Green Frogs have paired vocal sacs. Each time a rumble or a cluck is produced, the yellow throat pouch expands forward and around the sides under the ear drums. Air is forced between lung and throat and the whole body is involved in the thrust. The internal pressure even pushes out the ear drums a bit.  Up until now, I had assumed that a single gulp of air was alternately sucked and blown through the vocal chords during this process, but in looking at the video and examining my photos I discovered something interesting (perhaps even fascinating) was happening. During the actual noise production, the frog closed his nostrils and opened them to inhale between notes. Like any good singer, he has mastered the art of breath spacing.

This is not something that would be noticeable without film evidence. Take another look at the video sequence and compare the two calling photos. In the first photo (above and detail here) the frog is inhaling and the tiny nostrils are wide open. In the second photo (below) the frog is in mid-call and the nostrils are pinched shut.

That, my friend is the singular purpose of this blog. If you seek more, you’ll need to haul out a worn copy of the “Biology of the Amphibia” and take it to the beach for a good long read.

July 19, 2010

Herding Tigers

Filed under: Uncategorized — wykes @ 9:26 pm

Milkweed Tiger Tussock Moths are a gregarious lot when young. From the time they hatch out of the egg mass until they reach what is called the third instar (the skin shedding episodes that mark the growing career of all caterpillars are called instars) they feed, shed, and poop together. They munch along from milkweed leaf to milkweed leaf as a great hairy mass consisting of several dozen individuals – leaving only the skeletal leaves in their path (see below). Most caterpillars join together like this as a defensive tactic, but such doesn’t appear to be the case here.

There really is no need for these fellows to be defensive. By ingesting the cardiac glycosides in the milkweed, they each become immune to predator attack. They can afford to flaunt their noxious nature just as their monarch relatives do. So, you could say they do it because they can.  As one unit they act as a super caterpillar rolling over all that lies before them.

When they get a bit older, and head out on their own, they will flaunt themselves to the world as unedible balls of carpet. The scientific name of this Tussocked Tiger is Euchaetes egle – a name that translates from a combination of Greek and Latin meaning “well bristled shield.”

Their superb individual hairiness, even without their inner toxicity, alone acts as a predator deterrent. They are ornamented with alternating tufts of orange, black, and white hairs with a fairly tight row of bristles along the back (see here). This latter arrangement allies them with other members of the Tussock moth family who all look like bizarre toothbrushes. Personally I think a Milkweed Tiger looks more like one of those legless shaggy dogs that pace at leashes-end across the grounds at one of those fancy dog shows (without the little pink ribbon in the head hair, of course). I would suspect that these little dogs, by the way, would do well if released into the wild since they also are inedible carpet balls. Coyotes would choke on all that hair.

When I encountered this caterpillar feeding cluster they paid absolutely no attention to me as I crouched down to their level. My first few camera shots were executed without a flash and they all smiled appropriately. I used my flash for the final shots, however, and found that half the gang dropped off after the multiple explosions of light. There were but 10 or so left, along with some extremely stunted individuals who had been hiding under the layer of bristles (see below). I had, none-the-less, scattered the herd like a clap of thunder.

Those that abandoned the leaf simply rolled themselves into a defensive ball and plummeted to earth. It is likely that these skittish fellows were already at their third instar and were ready to abandon the security of the pack. As loners they will locate another milkweed, complete their growth, and emerge next spring as prim, lightly furred, gray moths.

July 16, 2010

A Loafing Squab

Filed under: Uncategorized — wykes @ 1:00 pm

In the movie “Fantastic Mr. Fox”, our hero delights in plucking tender squabs from the estate of Farmer Bunce (also chickens & cider from Mr. Boggis & Bean, but that is off my current subject).  Squabs are baby pigeons – the domestic variety in the case of the story – but also the name for all babies of all members of the pigeon and dove family. Very young Squabs are, with the exception of pelicans and naked mole rats, perhaps the ugliest of babies on earth. They do improve slightly with age. Wild doves such as Mourning Doves, therefore, produce ugly squabs and this brings me to the point of this posting.

I encountered a newly independent Mourning Dove squab the other day. I nearly ran it over with my riding lawnmower. It appeared from nowhere and was not there on my first pass by this location. The small fellow made no effort to move out of the way as if resigned to certain death by rotary blade. He made no attempt to escape when I hopped off to shoo it away and even remained stationary when I bent down to engage it in conversation. No, he only held that “dove in the headlight look” and hunkered down next to a yellow Hawkweed as if pretending I couldn’t see him (see above). I felt that it would allow me to pick it up and indeed it did (see below).

I placed the creature on a tree limb in order to get it out of the way, although it looked uncomfortable and unbalanced even there (see here). “You are a bird,” I told him, “and you must perch with more authority than that.”  It shifted its feet a bit after that remark and convinced me it would not fall out as I continued my mowing duties. “I’ll have to cut down your Hawkweed,” I remarked but saw no change of expression or position so returned to my tractor to do the deed. Later in the afternoon I snuck up on the mysterious squab and saw that it was raised up on its legs, actually perching rather than squatting, and fully asleep (see below). It looked more like a bad taxidermic mount than a sleeping wild thing but at least it was acting “normally.” By evening time the dove was gone and I was left contemplating what had just happened.

While the bird may have been out of sorts, it was not obviously sick or injured. I believe I can chalk up the whole thing to the fact that this was a squab still dazed by independence and yet un-wise to the ways of the world. Had I of been Mr. Fox, his little life would have ended before any further education was received. This bird was already at full size and possessed of most of its adult features. The scalloping pattern on the feathers and the presence of pin feathers about the face were the only remaining features that indicated youth (see here).  There was that behavior thing too.

Hatchling year Mourning Doves, those who have already left the nest, are notorious loafers. They are known to spend nearly 20% of their day doing absolutely nothing. During this time, usually in the mid-afternoon, they will sit for an extended time in a squatting position with their head drawn in. Loafing and sleeping are two different things in this case. While the young birds will engage in cat-napping while loafing, they actually are just zoning out (which explains the” dove in the head light” look). It is believed that this behavior conserves energy but if you ask me it is risky business.

I, of course, am never consulted on Mourning Dove affairs.  If I were, apart from doing away with this squab stupor stuff, I’d also send them all to nest building school and road crossing school. Mourning Doves build the flimsiest of nests and all hold the belief that they needn’t fly up from the road until a vehicle is within three feet of their location. Because doves are one of the commonest birds in North America, my advice is obviously not needed. I can only hope my little squab will get to the point where he or she can raise more ugly but successful squabs that will loaf their way into the future.

July 12, 2010

Doc Blanding’s Turtle

Filed under: Uncategorized — wykes @ 9:40 am

It wasn’t the first Blanding’s Turtle I’ve seen nor, I trust, will it be the last but it certainly was one of the finest.  With its bright yellow throat and chin (see detail here), dark blue-black carapace adorned with yellow sprinkles, and a two-part plastron this beast was all Blanding’s. Its shell length was around 10 inches – making it about as large as the species can be.  We, the creature and I, crossed passed a few days ago. Though our meeting was short, it was long enough to render a photo op and a chance to delve into a little bit of the animal name game.

If you are not familiar with these critters, please allow me to point out a few significant traits. First and foremost the Blanding’s is considered to be a “semi-box turtle.” Not as fully closable as the Eastern Box Turtle – a woodland reptile that can famously close up as tight as a drum when frightened – this species can close its front door if necessary. A flexible hinge (see below) allows the turtle to pull the front third of the plastron up once the head and feet are drawn in. The back end doesn’t close and so leaves the turtle somewhat exposed in the rear quarter department.  The front door thing, however, is sufficient to keep Jehovah Witnesses and vacuum cleaner salesmen at bay (as well as persistent predators).

The Blanding’s is also considered a “semi-aquatic” reptile which means that it spends a considerable time on both land and water. They can swim with dignity but can also traverse on terra firma using stout feet. As partial land dwellers they also have the ability to eat and swallow berries and terrestrial food without being underwater. Most turtles, with the exception of box & wood turtles, cannot swallow unless they are submerged. This critter can also chop down crayfish, and other aquatic fauna, with the best of the water dwelling turtles. Being pegged with two “semi” designations, you might think that this turtle is only partially real, but it is wholly unique among shelled reptiles. It is one of a kind.

The Blanding’s Turtle is so unique that it is placed in its own genus – no sharing with the likes of those commoners such as the Painted and Red-eared Sliders. The scientific name Cistudo blandingii was given this beast by John Holbrook in 1838. Holbrook , a nineteenth century naturalist, considered by many to be the father of North American Herpetology (in other words, the daddy of reptilemania) published a text in that year in which he provided the formal description of a turtle “first observed by Dr. William Blanding of Philadelphia, an accurate naturalist, whose name I have given this species.”  Thus in the early texts the animal was referred to as “Blanding’s Box Tortoise.” That name eventually morphed into Blanding’s Turtle and the scientific name evolved into Emydoidea  blandingii .

William Blanding himself was born in 1773 in Rehoboth, Massachusetts. He was physician by training and a naturalist by choice. He collected the original specimen from the Fox River in Illinois in 1830 and that pickled creature became specimen 26123 in the Academy of Natural Sciences in Philadelphia.

Today the Blanding’s Turtle has fallen upon hard times. It is protected in Michigan as it is throughout its restricted upper Midwestern range (there are a few in Massachusetts as well, although no one is sure how they got there). It is for the sake of the turtle and out of respect to the likes of Holbrook and William B. that we need to preserve this species. When gazing upon the wry grin of the Blanding’s Turtle (see below) one can almost sense this rich scientific heritage. “I am,” sayeth the turtle to the observer,” not just a turtle. I am Doc Blanding’s turtle.”

July 8, 2010

Where There’s Smoke…

Filed under: Uncategorized — wykes @ 11:30 am

It was one of those rare Saturday mornings. The morning sun was bright but not hot, the sky was a pure shade of robin egg blue, and I actually had part of the day off. I used that part of the day to try out a garage sale in Dundee, a small town along the River Raisin to the west of my home. Unfortunately, the “sale” was anything but – retail and eBay prices were the norm– so I turned back and took the scenic route back home.

The road follows along the wooded high north bank of the river past farm houses, barns, and fields.  It is a country drive. Long morning shadows over the pavement created a flickering effect, as if my traveling vehicle was part of an old movie scene. Small plumes of smoke were in evidence along the right hand side of the road wherever a shaft of sunlight was bordered by deep shade. Some of the plumes drifted over the road and dissolved as my truck passed through them while others danced and wavered as if being pushed by gusts of wind even though the morning was still and windless.

It is normal to suppose that where there is smoke there is fire, but on this occasion the smoke plumes were actually swarms of dancing flies called midges (“where there is smoke there is flies”, or something like that). I stopped to photograph one of the larger swarms at a spot located in someone’s front yard.  Fortunately the occupants didn’t emerge from their house to confront the kneeling naturalist taking pictures of air.  Had they of done so, I would have provided the following explanation…

When conditions are right – in other words still, clear, and sunny –tiny Chironomid midges are stimulated into love dancing. The tiny creatures emerge from the river and gather into huge flying swarms.  These clusters consist of male flies only. The stag parties collect over some feature of the landscape, such as a rock or a patch of ground illuminated by a shaft of sunlight, and there they engage in a rhythmic series of up and down movements (see above and here). Hopefully this explanation would have worked to prevent enforcement of trespassing regulations!

The vacillating dance swarm moved like the northern lights as they wavered to and fro (see movie sequence here). They took on the appearance of a super-being greater than the sum of its minuscule parts. All this activity generates a low humming sound which attracts the females. Upon hearing the wing vibrations of an approaching female, a male will dart out of the swarm, intercept her in mid air, and mate with her on the spot.  This activity will extend into the late morning and then resume at the other end of the day when the sun is again at a low angle.

Midges are members of the fly family. As larvae they live their life as aquatic residents living within small silken tubes attached to bottom vegetation and pebbles.  They feed on microscopic plants within the water column. Upon emerging, midges immediately take to the air and head for the dance floor, which is why these dancing swarms are always located near permanent water. The adults look very much like mosquitoes, but are much smaller and do not bite humans. The males and females look similar, but the males are easily distinguished by their plume-like antennae.

Not wanting to hang around the front yard too long (people in the country have shotguns, you know) I clicked my pictures and departed.  I didn’t have time to grab specimens but  I was able to find a few of the creatures plastered on my turn signal lights.  So, rather than leave you with only a movie of a swarm and a verbal description of a Dancing Midge, I can show you a detail shot of one of the dancing flies captured  in mid step (see below).  Framed against the orange background of the light, this portrait looks very much like one of those amber trapped insect fossils.  It is a still life of a stilled life.

July 4, 2010

Little Momma

Filed under: Uncategorized — wykes @ 9:16 pm

One thing you will never see is a cowbird young being fed by a cowbird momma. It just doesn’t happen because cowbirds never raise their own young. As nest parasites, cowbirds lay their eggs in other bird’s nests and let the “host birds” do the task for them. So, the sight of a tiny Chipping Sparrow diligently feeding a hulking cowbird chick (like shown above) is only slightly unusual.

Cowbirds are known to use over 40 host species in Michigan, but Chipping Sparrows are generally at the bottom of their victim list. Field Sparrows are preferred over Chippers by a ratio of nearly 9:1 (approximately, of course). One of the reasons has to do with the color of their eggs. When female cowbirds perform sneak egg-laying, they carefully remove one of the host bird eggs first and then later replace it with one of their own. They tend to look for eggs similar to their own brown-speckled white eggs. It is a matter of fact that Field Sparrow eggs, which tend to the creamy white and speckled side, look more “cowbirdy” than the blueish spotted eggs of the Chipping Sparrow. But, apparently this is not a set rule in cowbird land as evidenced by the mom/chick pair that occupied my front lawn for several days. They were living proof of at least one successful act of Cowbird/Chipping Sparrow sabotage.

The diminutive sparrow was stuffing insects into the open maw of her monster chick at a record pace – at least three times a minute. She was as diligent and prideful as if it were her own flesh and feather. In typical fashion, the nearly full grown cowbird would stoop forward, open her mouth, and wiggle her wings whenever her surrogate mom would approach with some recently acquired prize.

As a human, it is hard for us to understand how this mom could fail to recognize that the out-sized specimen before her was not one of her own offspring. You are tempted to yell out something, but there are no words to convey the proper thought without sounding callous (i.e. “this chick killed your babies – let it starve”). Human nature is not nature nature, however.

In a natural setting this chick was one of her very own from the beginning. She was there when the egg hatched and bound by instinct to care for her charges. The blindness of instinctive motherhood required her to feed the biggest mouth in the nest and thus starve out her own young in favor of the rapidly growing cowbird. In larger birds, the cowbird is able to become one of the brood but in small birds, like this one, the even smaller nest mates usually die – leaving the cowbird as the sole chick.

There is no need to get angry at the bumbling chick any more than it is to get frustrated at the zealous mom. In fact, this is cause to reflect on the ingenious system created by cowbirds long ago. It is believed cowbirds evolved alongside wandering herds of western buffalo. They ate the insects kicked up by the bison. Since bison herds are nomadic, the cowbirds had little time to nest and raise their own young before their food source lumbered on so they developed the ability to put their eggs out for adoption. The tactic was so successful that the bird continued to employ it long after the bison disappeared. Sure is has been damaging to some local bird populations, but that is another concern.

We are left then to view this mismatched mother/daughter pair (see here) in a strictly historical and behavioral sense and leave the hysterical sense for another time.

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