Naturespeak A naturalist's view of the world

August 9, 2007

A Darner Doodle

Filed under: Uncategorized — wykes @ 10:00 pm

  I’d like you to take a look at a drawing made by a Darner Dragonfly – a Darner Doodle of sorts.  Actually, my fingers held the pen but the dragonfly directed my every move back and forth across the page. I tracked his flight pattern for about two minutes, beginning at the lower center and ending at the upper left, before I was worn out.  You should know me well enough by now not to ask why I did such a thing, but I will say my effort was an experiment of sorts.

  Master aerial predators, all dragonflies seek and pursue their prey by employing their superior flight abilities and eyesight. Probably the most common method is to perch on a prominent branch or twig and fly out to intercept anything that moves.  This “sortie” technique conserves energy and permits an individual dragon to pick up motion anywhere within a 360 degree field of its eyes. 

  As a group, dragonflies are basically flying eyes.  One look at the face of a typical Darner will confirm this observation. (I can’t tell you the exact kind of Darner, because the mottled, shadow, common, green striped, black tipped, spatterdock, variable, lake and lance tipped look very similar.  It might be a female Green Striped Darner, but let’s just look at the eyes for now). They have two huge domes of vision (it hardly seems right to call them eyes) that consist of up to 30,000 faceted eyelets or ommatidium. You’ll note the black dot at the center of the eye in the photo. This is where you are actually looking down into the center of a bunch of facets – like peering down several well shafts.  The dot appears to move as you change your angle, so it seems like the creature is tracking you. You might call this the Mona Lisa effect.

  Their field of vision is close to a full circle – above, below, to each side and behind– even without moving their pliable little necks. Exactly what they see is up to debate. It is believed they don’t see clearly focused pictures but process the multiple images into a distinct motion induced view. There is even some evidence that they can see color & polarized light. If our local police force was equipped with a similar set of detection equipment, no one would escape a violation notice.

  Once a victim is spotted, this interceptor insect launches into flight and scoops the prey out of the air in it’s basket like array of legs.  It then mashes the quarry into a pulp using a powerful set of toothed mandibles. The order name for dragonflies – Odonota – basically means “Toothed Ones.” They often begin the eating process while still on the wing.

  The particular Darner dragonfly that I was observing wasn’t engaged in the usual sortie type behavior. In short, it didn’t seem to be landing at all, but was continuously coursing back and forth. I began tracking it to see if this indeed was the case.  After two minutes, my doodle indeed proved such to be the case. Indeedy doodle it did.

  Mr. Darner was continuously weaving back and forth over a territory of about 50 feet along an edge where a field met a line of scrub. It concentrated at the very edge of the thicket and only occasionally ventured out over the grass tops.  Once it veered skyward to unsuccessfully intercept a passing butterfly but quickly returned to the treadmill. The critter never paused during the whole time and likely would have traveled darn near the better part of a mile had the flight path been straight. For lack of a better term, I’ll call this hunting behavior as “patrol style” and it this was a fun way to document it.

  I never captured this hyper individual, but I believe it was a Green Darner. Greens are very common and very large members of the darner clan. Seeing the tremendous output of flying energy exhibited by the patrolling individual, it should be no surprise that this species is capable of migrating for hundreds of miles each fall.  They have been shown to move in a steady stream just like birds, but unlike birds their flight is one way.

  A recent article on the National Geographic site shows how micro-technology has permitted scientists to attach tiny transmitters to these insects in order to probe the mysteries of this migration. Soon researchers will be able to amass some flight data about the Green Darner and draw some squiggly lines of their own.  For now, however, I am satisfied to do it the low tech way with a pen, paper and a few minutes of daylight.

August 7, 2007

The Staypuft Plant

Filed under: Uncategorized — wykes @ 11:22 am

  Marshmallows are as much a part of summer as picnics, fireworks, and baseball games. There’s nothing better than one of those puffy white treats slow roasted to a rich golden brown hue over the campfire (although some slackers prefer to turn them into Tiki Torches before consuming them).  As a prominent part of the August marshscape, their amazing pink blossoms also provide nourishment for the soul.

  O.K., let’s back up a minute.  I realize that I am getting ahead of myself and mixing up my mallows and my readers.  I am actually referring to two different marshmallows here.  The first is found in a bag at your local grocer and morphs into a “Ghostbusters” character, while the second is found in your local wetland and morphs into a stunning tropical beauty.  The first is linked as one word, while the second is divided into two – Marsh Mallow. While it may seem only a coincidence, the relationship between the two is closer than you may think.

  The Marsh Mallow in question is more properly known as the Swamp Rose Mallow (a mallow of the marsh). This shrubby perennial grows in wetland conditions and pretty much hides out among the cat-tails throughout the growing season. During the mid summer blooming time it screams for attention.  Take a look at this photo of the bloom and I think you’ll agree it’s a real looker! The flowers are 4-6 inches in diameter and graced with 5 tissue-like gentle pink petals. A central spike is covered with anthers (the male part) and terminates into five pistils (the female part).

  The attention being screamed for is that of pollinating insects.  Take another look at the previous picture, or the following one, and you’ll note that the blossoms are crawling with attention in the form of flea beetles. While I’m sure they appreciate our gaze with some form of inanimate plant psyche, it’s the beetles they are after.

  The usual human reaction to this bloom (after the “wow”) is that the flower looks like a garden Hibiscus.  At this point, were you and I standing in front of one, I would whip out a card with the scientific name on it and confirm your suspicion.  The Latin name for this pink variety is Hibiscus palustris.  The garden Hibiscus, this Rose Mallow, and even those old fashioned Hollyhocks are all in the plant family called Malvaceae – the Mallows. There are over 1,000 kinds of plants in this group and most of them are tropical – thus the exotic appearance of our marsh plant. The family name means “soft” and certainly is appropriate when one considers the Staypuft connection.

 Before we turn our attention to the puffy white confection, there are a few more things I’d like you know about the Swamp Rose Mallow. Take a look at this photo of a fresh flower next to a wilted one.  The mallow is one of the few plants whose wilted petals are actually more colorful than the fresh ones. The limp blossoms look like crumpled art tissue ready to be applied to a Homecoming float.  Eventually, the fertilized flower sheds its petalware and concentrates on the seed head – a compact five parted package (see here).  By late fall, these pods turn dark brown and open up like yucca pods to distribute their seeds.

  Another member of the Mallow family, the Marshmallow, is responsible for the name of the sugary confection of the same name. This European plant doesn’t hold a candle to our Mallow in terms of floral beauty, but holds a secret within its mucilaginous root. Mucilage is a fancy term for a jelly substance and all mallows, including ours, have the gelling substance in their roots.  The Marshmallow happens to have a very high concentration of it.  This property has allowed it to be used for candy making for centuries. The Egyptians used it, the French used it (pate de guimauve), and the British as well. Those treats can collectively be called “marshmallows.”

  Traditional marshmallow recipes called for the powdered mallow root, egg white, cane sugar and vanilla extract.  Since the mid-1800’s, commercial marshmallow manufacturers have resorted to other gelling agents to do the job.  Out of employment, the original marshmallow plant now shares only a name with the Staypuft Marshmallow Man.  So, by virtue of being a cousin twice removed, our Swamp Rose Mallow can claim the title as well.

August 4, 2007

A Fallen Giant

Filed under: Uncategorized — wykes @ 8:59 pm

  The passing of a great oak is not something that should be taken lightly.  Not far from my house, one of these noble life forms was brought to the earth, and – although I didn’t know the tree personally – I feel compelled to write a short eulogy in its honor. 

  A combination of small internal forces combined with overwhelming external ones to bring down the centuries old White Oak.  Internally, it was riddled with the passages and tunnels of Carpenter Ants who ate away at the support foundation. Hundreds of generations of these large black ants had chewed away at the stout heartwood -the dark inner support wood of the oak – and robbed it of its essence.

  As trees grow, the outer sapwood responsible for transporting sap to and from the root system is eventually relegated to a crucial support role as time goes by.  Resins eventually build up in the channels and solidify the wood into an iron-like core. Tons of living tissue in the form of leaves, branches and acorns are supported by the heartwood. This White Oak heartwood is legendary for its strength and resilience. The wood has long been on the A-1 list for old time ship builders, barrel makers, and furniture makers.

  Our tree never had to offer up its heartwood for human use, however.  Instead it continued to grow over the better part of 800 seasons and 200 years.  Without the interference of humans, disease, weather or insect damage, White Oaks can reasonably expect to live over 500 years and therefore have the capability of being among the oldest living things on earth. Achieving this rank is not an easy thing to do.

  White Oaks produce acorns every year, but only come out with a big crop every 4–10 years. The parent tree for our fallen giant had to run a gauntlet of factors in order to insure that its seeds survived into tree-hood. Observers have noted that a typical tree can produce over 23,000 acorns in any given season, but from the time they fall from the tree their survival chances begin to take a precipitous plunge.  Ten percent of the acorns are no good to begin with and a most of the rest are eaten by deer, squirrels, or weevils. Of the very few that survive intact (perhaps buried and forgotten by squirrels) only 6% are still able to sprout after six months. This leaves us with only a handful of acorns capable of sprouting the next spring. Of those that do sprout, most of these die from drought, browsing, or disease.

  Given the above statistics, the fact that our oak even became a tree was a miracle in itself.  At every point in its life, there was danger from wind, lightning, disease, or the lumberman’s axe. Since White Oaks are legendary for their attraction to lightning, it is small wonder that the Druids associated them with the God of Thunder.  Oddly enough, they were also known to place an acorn on their window sills to prevent lightning strikes.

  As far as I know, no local Druids gathered at this tree for any ceremonial purpose, but it avoided Thor’s wrath none-the-less.   Slowly but surely, the tree advanced to the stage of a giant along the edge of an open field.  With no nearby competition, the tree was able to spread out its huge side limbs – which became nearly as large as the main trunk. The passage of a road a century ago and construction of a house some 50 years later left it intact.

  How many fox squirrels gathered the annual acorn crop, how many spring warblers sought insects among its branches, how many orioles suspended their basket nests from the branches we can only speculate.  That an incredible amount of minute insect life lived, died, and thrived within the protective canopy there can be no doubt. The generations of Carpenter Ants set up the final act.

  A few weeks ago, a tremendous wind storm whipped through the region. It was Aeolus, not Thor, which rocked the mighty tree beyond its breaking limit.  The unequal balance created by the huge side limbs was no longer supported by the heartwood and the oak tipped to the side and split up the middle (see it here).  This was a fatal wound and the end of a long life.

  A few of the offspring of this tree have survived the initial stages of life’s journey and it is now their job to continue the line.

August 1, 2007

A Conversation with a Screech Owl

Filed under: Uncategorized — wykes @ 8:02 pm

  I ventured out into my front yard last night to take in the symphony warm-up.  A mid summer’s evening is a soundstage for Field Crickets, Snowy Tree Crickets, Cicadas, and a whole host of other insect crooners. Their season is just beginning, so this time of year equates to the tuning session just before the orchestra plays – the response to the Concert Master’s “A” string. By the time September rolls around the nocturnal orchestra will rise to full symphonic intensity under the direction of nature’s baton.

  It was around 9:20 in the evening and the intense heat of the day still hung heavy in the air.  The sun had fallen into the distant sea some time ago and the first hint of star shine was breaking through the darkening veil of night. A leaden gray blue sky starkly silhouetted all the tree branches against it.  Slight puffs of breeze elicited hushes sounding like waves on a beach. Between the crickets, the breeze, a distant train and the faint rumble of a Harley I detected another familiar sound. Barely audible above the hum of life there was a low whinny call wafting it’s way over the fields.  The sound was issued from far off and was so low as to seem imaginary or ghost-like.

   I held my breath to better pick it up and the whinny repeated. It started high and descended into a hollow tremulous end: “Wheeeeeeee- eeeeewwww    Wheeeeeeee- eeeeewwww.”  Though the roar of a passing car obscured the next few calls, the spirit call was still there as the auto whine dissipated down the road.  This night I was honored with the presence of a Screech Owl. He was practicing way off in the wings (every pun intended, by the way), so I decided to have a few words with him and see if he couldn’t come a bit closer. I called out his name.  Normally this is not good etiquette for orchestra goers, but acceptable if the inquiry is executed in the proper tongue.  I speak a bit of Screech Owl, so felt justified in the effort.

 Cupping my hands around my mouth I aimed a verbal imitation of the “wheeee” call in the direction of the unseen owl – ending with a long gurgled “ewwwwwwwwwww” using that flippy dingy thing in the back of my throat (the epiglottis).  I’m not entirely sure what I said, only that it basically mirrored whatever he was saying. To his “I am here, I am grand, look at me, here I stand,” my mimicry probably comes out as “Cheese is dog, swollen feet, my elephant is chow dungaree.” 

  I waited for a second, but heard no response. I looked around to detect any movement in the sky above, but only noticed a silent Shamrock spider above my head. She was busily engaged in weaving her web. Every detail of her plump body was sharply defined in silhouette. I puckered up again to call, but made sure to put a different emphasis on the end note this time –perhaps inferring a slightly different meaning.

  Again I waited. The spider continued her chores and a lightning bug flashed but there was no verbal answer. This time, a motion caught my eye as the owl streaked over the sky space and landed in the Red Pine to my right. It immediately began to call for further response. It worked.  Now it was time to carry on a decent conversation.

  Eastern Screech Owls are the smallest resident members of the owl clan in our area. They are about the size of a large can of soup (about 8 inches from beak to tail end) with a wingspan barely exceeding 18 inches.  They are very common, but as nighttime hunters are rarely seen. In daytime, they appear as variations of mottled gray or red-brown with prominent “ear” tufts and huge yellow eyes, but in dim light they are evasive shadows. Take a look here to see what they look like and to hear that mournful call (click on the three call recordings).

    Now that I had his attention, I let out a “Wheee” call to set the tone of the conversation.  From the depths of the Red Pine, the owl answered with a new set of notes sounding like a long muted trill.  Although it was issued from only 30 feet away, the call had a ventriloquist nature to it and sounded far more remote.

  We carried on for a few moments, but my responses were getting weaker as my mouth dried out.  With each call I was sounding less and less like an owl and more and more like a cheese dog with swollen feet. The owl continued to be indulgent and curious, however, and flew back over my head to the maple on my left. I saw it land, but it instantly disappeared in the shadows.

  At this point I was sure we were both doing the same thing. I rocking my head from side to side trying to get a fix on the bird and he trying to figure out the exact nature of this huge mutant ground owl below him.  His final call was clear and confident: “Wheee-eeew, Wheeee-ewwww, ew ew eweweweuuuuuuuuu….”  By this time, I had no more moisture in my mouth and I tried to answer, but it stuck in my throat.

  As if to indicate that the game was up, the Screech Owl limb-hopped to a location just over my head and paused before launching into a silent departure.  The night returned to the crickets.

  I’m guessing my heavy accent gave me away.

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