Naturespeak A naturalist's view of the world

May 30, 2009

High & Mighty

Filed under: Uncategorized — wykes @ 11:09 pm

Most turtles are sun worshippers. They make it a habit to reap a daily harvest of solar energy. The closer these poikilothermic (cold-blooded) beasts can get to Old Sol, the better. For an aquatic turtle “getting close” usually means climbing the gentle slope of a rock or scrambling the low incline of a stump in order to intercept the life-giving rays. Sometimes it even means climbing on top of their fellow shell mates in a game of one-upmanship. Because swimming appendages do not make for good climbing tools, what ever height is obtained is normally not all that lofty.  There is, of course, always an exception and I’d like you to meet him (see above).

The exceptional example pictured above is a Map turtle (see close up here). These turtles are so named because of the wavy road-like lines on their shell, although they are equally well marked with yellow highways on their head, neck ,and legs.  As a species they tend to be mountain climbers, but this particular turtle was pushing the atmospheric limits when I encountered him late yesterday afternoon. Three of his four legs were dangling freely into space and the center of his plastron was squarely set upon the root tip. There was nothing but warm dry air surrounding this turtle. Normally these fellows are quite skiddish and will tumble into the water at the slightest provocation so I snuck up behind a tree and snapped off a view before this remarkable scene was lost. 

There are many reasons for a turtle to bask, and I reflected on those reasons as I watched Sir Edmund Mappery.  The primary reason is to raise the internal body temperature to the required 28 degrees C, but that thermal rise achieves many other positive results. High temperature promotes good digestion, for instance,  and accelerates egg development in females. The activity also aides in the synthesis of Vitamen D. One of the less appreciated benefits of drying is to discourage parasites and algae growth – a good blow dry to shed nasty leeches.

All this is fine and good, but a basking turtle is not all that exciting to watch. Even the presence of an additional two turtles to the branch (see below) failed to notch up the personal excitement level. Sensing the opportunity to get a great shot of a diving turtle, I focused in on my subject and started to wave my hands about to see if I could make him take the plunge. Despite my best efforts, the turtle sat there as if glued to his post. I stepped out from behind the tree, expecting him to bolt, but he remained.

I walked down the shore and gesticulated, but he showed no desire to move what-so-ever even though he was only about 25 feet away. I was getting warmed up in the late day sun, as a matter of fact. Even tossing a few pebbles into the water failed to elicit any reaction.

About this time a family walked up the shoreline and I flagged them down. “See that turtle over there?” I asked. “I’m trying to get him to jump and I need your help. Could you walk back over that way and wave your hands?”  Again I focused in and waited. They agreed and performed as requested but turtle remained stoic. The scene in my view finder remained a still life. 

I was ready to give up at this point, but the dad picked up a large boulder and instructed his son to do the same. “We’ll give you your National Geographic moment,” he said proudly. “Just tell us when.”  For a moment I felt a twinge of guilt come over me as I realized that I was about to encourage an act of wildlife harassment. I quickly overcame this feeling, however, and calmly gave the go-ahead. There was some warm-blooded pride to uphold.

The pair gave the rocks a mighty heave and they both landed only a few feet in front of  the high and mighty turtle. Tremendous plumes of spray shot into the air as if two depth charges were set off. My viewfinder temporarily filled with white and I expected to see an empty perch when it subsided. The shock waves radiated out and rolled across the water. Even though the act sent his two other log mates packing, the king of the root remained in exactly the same position. He looked directly at me (see below) and smiled.  Apparently, basking also produces extreme self confidence. We all gave up and left.

Today I returned to the spot just to make sure that the turtle wasn’t actually glued to the root. Indeed, he was there again, but was re-positioned at a point just below the tip. As I watched, a cloud shadow passed over the waterway and the turtle  frantically plunged into the water like a scared rabbit.

May 27, 2009

The Gray Matter of a Blackbird

Filed under: Uncategorized — wykes @ 9:20 pm

I was speaking to a group of gardeners last week about spring things like walnut flowers, woodcock dances, and the miraculous generation of baby possums.  One of the things I mentioned was the curious case of a red-winged blackbird with half a voice. “It was a handicapped bird with a head wound,” I said, “and it could only produce half a call.”  The group uttered a spontaneous and compassionate “awww…” upon hearing this. The intensity of the reaction took me by surprise, so I jumped on the sadistic opportunity to state that the creature then died right in front of me, fell from it’s tree-top perch, and landed stone-cold dead on the ground – at which point I kicked it’s lifeless form into the shrubbery and callously walked away.  This, of course, was not true, but the moment of shocked silence was a wonderful thing to behold. “No,” I quickly reassured them, “Handicapped does not mean helpless and weak. This bird appeared to be doing fine and, as a matter of fact, had a wife!” Shock turned to laughter and relief as they asked for the details.

I came upon that half-song bird on a blustery warm day at Crosswinds Marsh. I was listening to the twitterings of a marsh wren when a loud unidentifiable call accosted my ears from  behind. Though the sound had a familiar ring to it, the manner and deliverance were odd. A lone male red-winged blackbird was perched high atop a stubby maple at the point where the sound came from.  The call was vaguely red-wing like, but not enough to make me say that this bird was the culprit. No other bird was in sight or sound, however, so I focused on him.

True to his sex, the creature started to issue the standard “check” call – which is a sort of warning call. Unlike the usual robust call produced by this species ( listen to the full warning call of another bird on the same day), his call was thin and tinny ( listen to his warning call).  The sound was, at times, lost among the hefty gusts of wind that circled about us. The thin-voiced male was persistent and, oddly enough, hung around in spite of my presence. No matter how close I got, he stayed put. The usual red-wing ploy is to chat away and then fly off to a distant perch, but this guy was acting somewhat docile.

I was able to take a few shots of the bird as it called and rode the swaying branch (see above). It was then that I noticed that it had a distinct notch in his head feathering. After it finally switched positions and landed on a nearby cat-tail, I took one more shot and could plainly see that exposed patch on the bird’s head. It seemed to have a head wound of some sort (see below).  When the bird finally belted out that odd grouping of syllables that I’d heard initially, I knew this was the bird in question.

About the only way I can describe that particular call is that it sounded like half a call – the duration was full but the quality was halved. Red-winged blackbirds usher the familiar bubbly “Oakalee-a” call as a vocal territorial marker, and they employ a unique blend of duel harmonics to give their calls a rich tonal quality. Try as I might, I was only to capture a brief snippet of this “half call” vocalization (listen to Partial Call here). My audio equipment actually caught a bubbly chortle that I hadn’t noticed before.

Since I never got a chance to examine this bird as a lifeless little corpse, I can only surmise that the quality of this blackbird’s song was somehow related to the head wound. Songbirds have a divided syrinx which, unlike our voicebox, divides into two “instrumental” parts. Sound frequency and amplitude is produced by a controlled air flow. Amazingly, these two halves can be separately controlled in order to produce two parallel harmonic lines. In other words, birds can harmonize with themselves.

Each side is controlled by separate nerves, referred to around the water cooler at the bird biology lab as the ipsilateral tracheosyringeal branch of the XIIth cranial hypoglossal nerve. Interruption of one of these nerves will shut down one element of the song production. Damage to one side or the other will cause missing harmonics, lowered volume and other such aberrations.  In layman’s terms, I suppose you could say that the song is cut in half. Since this nerve control originates in the brain, it would not be that startling to say that the head wound in evidence on this bird was sufficient to damage this connection.

Without any further evidence, I’ll have to leave the case of the half-voice blackbird right here. I am happy to report that this male had a mated female in his territory and it was a normal female to boot. In the harsh judgment of nature, handicaps – even small ones – are not usually tolerated, but apparently the fates do occasionally turn away their glance.

May 24, 2009

Pump’n Up a Polyphemus

Filed under: Uncategorized — wykes @ 6:41 pm

I discovered a Polyphemus moth cocoon this past winter (see here) and decided to leave it in place  for the duration of the season. It was in a “conspicuous” place , at least for me to find it again, but still cryptic enough so that I felt a hungry woodpecker or mouse wouldn’t get to it. I finally collected the silken wrapped package about three months ago and hung it up in my unheated back porch. Last year I had the good fortune to find  and eventually hatch out a beautifully plump female moth and I awaited this late May season with great anticipation (see earlier Naturespeak).

The moth that magically appeared yesterday morning was not a female, but was a magnificent male – one of the largest I’ve seen in some time (see above). In the world of giant silk moths the females are usually the largest but this robust male was giving the gals a run for the money. Male moths possess a huge set of feathery antennae (see below) and are easily identified because of this. Those sensitive organs can pick up individual hormone molecules sent by distant females and it’s likely this guy had already netted a few love notes. He made his entrance late on the previous evening and was ready to try a run at those gals by the time I met up with him.  It was up to me to open the door and let him go.

Large silk moths like this can’t just fly away on demand, however. When first contacted they instinctively drop to the ground, flare their wings, and flop around for a bit. In doing so, they expose a pair of intimidating “blue eyes” (see below) on their back wings in an effort to scare the potential predator. The bluffing attempt buys some valuable time – extra minutes to live and extra minutes to charge up their flight batteries. Like many insects, they need to warm up their muscles before flight is possible. This feature is called obligate heterothermy. 

I carefully grabbed the moth’s wings between my forefingers and thumb, before it had a chance to drop (see here), and carried it outside. The events which followed provided an opportunity to see how a Polyphemus gets up to speed. Take a good look at this video sequence here and you’ll see  the  essence of the “drop, flop, shiver, and fly” routine. Once the moth drops to the ground it flops about – apparently at random, but actually well performed so as to keep the eye spots facing up.  The third stage, the shivering part, generates internal heat. Depending upon the species, this required temperature is around 95 – 102 degrees F.  Who says insects are “cold-blooded?”

Experiments on captive moths have shown that the duration of this shivering activity depends on the surrounding temperature. If the ambient temperature were 95 degrees, for instance, the shiver time would be minimal. It was 60 degrees F on this morning and it took about five minutes for this moth to reach the proper take-off heat. I eventually picked it up, expecting it to drop again, but it finally broke free and quickly flew off. Flight itself generates the heat needed to maintain the critter’s cabin temperature at the proper level and the furry coating of body scales acts as an insulating layer to hold it in.

I watched the Polyphemus gain height and vanish over the tree line. I’ll admit that I half expected a Flycatcher to swoop down and engage it in aerial combat, but this did not occur. I can only imagine that this hot-blooded creature found a secretive hideout where it could wait out the hazards of the day before charging up for an exciting night of hormonal bliss.

May 21, 2009

An Eight Legged Deer

Filed under: Uncategorized — wykes @ 5:47 pm

It was a rainy gray morning when I encountered “my” Killdeer standing in the grass just off the road. I had been watching this bird – actually a mated pair of birds – over the course of the last month. They had located their nest on the narrow shoulder and would greet me with a fine defensive display every time I slowed the car down to get a better look.  I never saw the eggs, but knew they were there simply because the parental birds were employing their “broken wing” act to lure me from it. It was an impossible location which required them to react to every single  passing car.

I figured that the adults would die of exaustion long before their eggs were successfully hatched. I, of course, was wrong and they did produce a fine little batch of killdeerlets in spite of my views.  Three fluffy little chicks became regulars at the site over the course of the following week. They would dash for the cover of the long grass or drop and freeze at the panicked request of  the frantic parents when my “dangerous” Chevy Blazer passed.

As I pulled up on that rainy day I saw only one adult. It was down in a crouching position and appeared to have sprouted a few extra legs and tails (see photo above). Since both parents usually share duty and always look alike, I can’t say whether it was the male or the female. Just to be fair in this matter,  I’ll call it a “he.”  Like a mother hen, he was sheltering his charge from the elements and paying little attention to me.  The more important question in this situation was how many birds were hidden under those wings. He looked to be at least four legs over the individual average, but it was hard to tell.

My answer came after a few minutes when the rain stopped and my presence became the sole source of irritation. The male then rose and stepped aside to reveal the presence of all three chicks (see below). This eight-legged Killdeer quickly divided into four two-legged birds. The fluffy young ran for cover and dutifully performed their freezing act upon discovering they were no longer under wing. They milled about for a few confused minutes before enacting their plan, however.

In the bird world, there are those who rear altricial, or helpless young, and those who produce precocial, or independent young. Birds, such as the killdeer who nest in exposed places, have wisely chosen the evolutionary path that led them to precocial young. Such chicks are down-covered and able to leave the nest soon after hatching in order to escape predatory eyes. They are able to feed themselves as well, but still require an adult hand – or wing.

Even when the chicks are away from the nest, the adults still protect and brood them for an extended time period. This care is almost constant for the first three days and is administered off and on for the next 14 days. At 17 days, the young acquire their full thermoregulation capabilities along with a new plumage – going from a single breast band and a downy speckled look (as seen below) to a double breast band and some real feathers. At five weeks they can fly and are truly on their own.

Based on this schedule, the parent birds will not have to pull mother hen duties for too much longer. In spite of all these attentions, the family has experienced a loss sometime this week. Today, only two chicks fled my approaching car. From the original clutch of four eggs, only three made it to chickhood, and only two of those made it into the second week of existence. It’s hard to say what predator nabbed the last chick, but mink and cooper’s hawks are potential culprits. One killdeer brood in Jamaica Bay, New York , was completely wiped out by a persistant kestral who even reached under a log to snatch one of the hiding killdeer chicks. Even though these small birds of prey don’t normally make it a habit of eating killed-deer meat, they are opportunists.

No matter how you look at it, subtraction always follows addition in the natural world.

May 18, 2009

One Born Every Minute…or So

Filed under: Uncategorized — wykes @ 5:29 pm

I think it was P.T. Barnum that said something about a “sucker being born every minute.”  If he didn’t, well, he should have. It was a show-mans job to sucker people into spending their money under the big top. Whoever said those prophetic words, I am pretty confident that they were talking about people and not fish. That phrase, however, would fit certain finny residents found under the big Detroit River. Deep down on the spring spawning beds, suckers are literally being born every minute …or so. By this I mean sucker fish.

Although the Lake Sturgeon eggs claimed the spotlight on my recent trip aboard the USFWS Sentinel, there were plenty of sucker eggs in evidence on the egg mats as well. These fish spawn in the mid-spring while the waters are still below 60 degrees. It is at this time of year that the little suckers start their journey toward becoming big suckers! There are many different kinds of big suckers in this river, so it would be unfair – a sucker punch as it were – to refer to them as one type of fish.  All of them are bottom feeders with downward pointing mouths and all are members of the minnow family, but beyond that they have unique traits and habitat needs. 

One of the research nets snagged a nice Silver Redhorse Sucker just upstream from the spawning beds, so this gives me an opportunity to introduce one of these fish to you. As you can see by the portrait (see above) the Redhorse is a lovely fish with protruding lips, gentle eyes, and a big head. This chunky individual was about 24 inches long and covered with large yellowish-green scales. Scientifically, this species goes by the name Moxostoma anisurum which means “sucking mouth fish with an un-equal tail” in Greek. As part of the Redhorse clan it has reddish fins and a horse-like face. Perhaps you’ve  heard the one about the Redhorse sucker that went into a saloon? The bartender, sensing the need to talk, went up to him and asked  “so, why the long face?”  It is well known that they drink like fish, so this story is likely true. The Silver Redhorse is separated from the other long-faced Redhorse species (the Black, Golden, River, Short-headed, and Greater) by a solid gray tail, a convex dorsal fin, and a “V” shaped angle in the bottom lip.

Take a good close look at those lips (see below) and you’ll see that angle expressed as a split lip. Among suckers this mouth is considered “small,” believe it or not. There are many fingerprint like grooves on the surface and you’ll note that the ridges on the bottom lip break up into bumps called papillae.  I suppose it would be more appropriate to call this the “back” lip since the natural position is behind the “front” lip – it is only the “bottom” lip when the fish are standing at the bar!

This Silver fish was evidently a male involved in the spawning business. His orange tinted anal fin and the lower half of his tail were covered with white bumps called tubercles (see below and here). These structures only appear during the breeding season when the fish are charged up for love. By early June, the bumps magically disappear and the fish revert back to their solitary ways.

We released this sullen-looking Redhorse back into the river after recording a few vital stats. No doubt it quickly resumed his habit of  hanging out at the local gravel bars and living the life a poor sucker.

May 16, 2009

I Have Seen the Future

Filed under: Uncategorized — wykes @ 10:39 am

On my second trip out on the “Big D” (the Lower Detroit River) aboard the USFWS research vessel Sentinel, we failed to catch any sturgeon on the set lines. You can’t blame that, however, on Jim Boase or Dr. Manny, the fisheries biologists in charge of the operation. This is fishing after all and sometimes you get ’em and sometimes you don’t.  This is not to say that we didn’t see any sturgeon that day. In all, you could say that we saw ten fish, but I’ll need to explain this statement. Although our view was completely different than previous trips, it proved to be some of the most exciting sturgeon viewing yet.

The USFWS tagging operation is not the only on-going sturgeon effort taking place on the river. A crew from the U.S. Geological Survey (USGS) was also engaged in survey work in the Fighting Island Channel (see here). Last Fall, an experimental spawning reef was laid across the bottom of the river from the north tip of Fighting Island to the Canadian shoreline at LaSalle. Consisting of a band of mixed gravel and large stones, the reef was intended to provide the type of bottom substrate that sturgeon require for egg-laying. This spring was the first opportunity to see if the great fish would give it their stamp of approval and the USGS team, aboard the tiny but mighty R V Sculpin,  was there to check for sturgeon spawning activity.

Searching for fish eggs can be a needle-in-the-haystack kind of operation, especially given the swift-flowing current and 28 foot depth in that portion of the channel.  Egg mats, rectangular metal frames covered with filter material, are randomly laid across the bottom in order to overcome this sampling difficulty. These units are about as low tech as you can get – a tribute to governmental frugality, as a matter of fact. The material itself is standard furnace filter cloth and the clips used to secure it are of the Office Depot variety. The sticky eggs adhere to these mats and can be viewed when brought to the surface. Members of the research team were actively engaged in this activity as we pulled up alongside (see below & here). 

There were plenty of eggs attached to the filter material. Most of them were Sucker eggs, this being the peak of their spawning season, but the presence of Sturgeon eggs provided ample evidence that the fish were indeed capitalizing on this new spawning venue. One of the crew offered up a small container containing nine brownish-grey eggs as evidence (see beginning and below).  They were about 3 mm. in size and surrounded by a clear “shell.” There was little effort to conceal the obvious joy felt by all at this discovery. These eggs were but a small sampling of the activity going on far below.

Lake Sturgeon breeding is a hit or miss affair. The males don’t participate until they are sexually mature at 15-20 years old, and the females wait until they are a bit older than that. Even when able, individuals don’t spawn every year. Males undergo the effort every 1-3 years and the gals space out their participation at 4 to 6 year intervals. This means that only a small portion of the population actually spawns in any given year.

When spawning does take place, the females – heavy with a full crop of up to 700,000 eggs – arrive over the gravel beds under the escort of several eager males. As the “hen” broadcasts her eggs over the site, the males vie for position in order to fertilize them as they exit her vent.  There’s a lot of bumping and grinding going on as the fish wrestle for position over the course of several days. It’s not an affair for faint-hearted fish! Once fertilized, the eggs become sticky and drop down into the gravel and eventually settle down into the small spaces between the rocks. Some of these eggs, of course, end up landing on the egg mats.

Those eggs that remain on the bottom are oxygenated by the stiff current and hatch within ten days. The emerging fry will burrow down  into the gravel and stay there for an additional ten days. Then, in a co-ordinated motion, they all ascend into the water stream and vanish!  The next time they show up in this part of the river they are two year olds. No one is sure where they go during the first few years of their life.

Before leaving the spawning site, we lowered an underwater camera over the gravel beds to take a look around. For the most part, all I saw was a bumpy view of a field of rocks  looking like a lunar landscape.  Suddenly, out of the murky depths, the camera revealed the shadowy form of a sturgeon over the bed. The fish darted off before any details could be seen, but there was no doubt that the fish were spawning as we drifted over the reef.

Between this sighting and the wonderful handful of eggs, I do believe I have seen the future of a magnificent fish. The future looks good.

May 13, 2009

A Big Fish on the Big D

Filed under: Uncategorized — wykes @ 12:35 pm

If you’ve been keeping track, you will notice that this is the fourth time I’ve brought up the subject of Sturgeon on this blog. Every time I go out on the U.S.F.W.S. research vessel on their Lake Sturgeon survey and stand in the presence of one of these giant fish, my fascination is re-kindled. When I am kindled, my readers are the first to be affected (or infected, depending upon your view point).

Since the subject has been explored before, I won’t go into the fine details of the research other than to mention that it is conducted on the lower Detroit River under the supervision of fisheries biologists Jim Boase and Dr. Bruce Manny. This team has been conducting a long-term study of Lake Sturgeon biology and ecology on the river. As part of their work, it is necessary to gather data from individual fish. From aboard the aluminum hulled vessel Sentinel, set lines, each with 25 baited hooks spaced about ten feet apart, are placed in about 30 foot of water around the vicinity of Fighting Island. The lines are checked daily and the captured fish are weighted, measured, transmitter tagged, and released. My role in this thing is an impassioned volunteer and to assist with the duties.

We captured four sturgeon on my first trip last week. Three of those fish were secured on one set line, which is somewhat unusual. The smallest was about 15 pounds and measured about three feet (only in the world of giants would such a fish be called “small”) while the largest measured about five feet from snout to tail end and tipped the scales at 60.5 pounds (see here). I was quite satisfied with these fish, but Dr. Manny still talks about the seven footer they nabbed last year. “That fish,” he proudly boasts while holding out his hands in an arc, “had a girth of over a meter.” I remember him describing that same fish last year and accused him of upping the size each time he talks about it – he doesn’t, but I like to chide him anyway. I get the feeling that Herman Melville might appreciate this big fish story.

We all hope to re-capture that legendary beast again. On my second trip this year, one of the hooks came up empty and was bent horribly out of shape. The consensus was that  “Moby” was responsible – perhaps.

Content with the fish at hand, however, I made it a point to concentrate on some of the unique features other than size. Sturgeon come from an extremely ancient lineage which dates back some 200 million years. Over all this time, they have changed very little in appearance because their original design left no need for improvement. There are over 20 species of sturgeon today, but only the Lake Sturgeon is found in Great Lakes waters. Like all the sturgeon species, old and new, they are possessed of a cartilaginous notochord, rather than a segmented backbone, and are equipped with bony plates embedded in their scaleless skin. In other words, the only bony part of their internal skeleton is their head capsule.

We didn’t re-capture the “really big one,” but the largest fish of the day was a re-capture. A scar on the left front, or pectoral, fin indicated that this individual had been sampled before (see here). One part of the data collection process is to cut off the first fin ray for aging purposes. When this activity is first executed, the surgery leaves a raw-looking gap. It was good to see how this portion heals over after a few years. Another indication that this fish had been deck-side before was the presence of an embedded transmitter called a PIT tag. The transmitter set off a signal when a detector was passed over the region just back of the head. This fish was missing the old FLOY tag that was once attached to the dorsal fin, but a new one was supplied in its place before the fish was released (see below).

A raw lamprey scar on the body just behind the dorsal fin provided graphic evidence that a Sea Lamprey had fed off of this giant sometime in the recent past (see here). It appears that research scientists are not the only sturgeon samplers out there. Lampreys come from a line of parasitic fish that pre-date sturgeons by some 100 million years, so they have been at their task since day one. One of the unique behaviors of the Lake Sturgeon is that they are known to jump out of the water like breaching whales. It is believed that they may do this in order to dislodge pesky blood-sucking lampreys (or annoying FLOY tags).

In profile, the head of the Lake Sturgeon is a thing of primitive beauty (see above and here). Just ahead of those expressive eyes are the two-parted nostril openings. The nostrils of fish do not open up into the mouth cavity, but instead enter into a sensory pocket in the head. In this case, incurrent water is taken into the first opening, passed over the sensors, and then excurrented out the second. There is a peculiar star-like organ within this chamber that you can see in the first picture.  Dangling from ventral part of the snout, four fleshy barbels, or whiskers if you like, are used to “feel” the bottom and detect potential food items such as invertebrates, snails, or crayfish.

When viewed from below (see above) these barbels share their space with dozens of electro-sensory pores that dot the white flesh surface of the snout.  The entire head is equipped as a super efficient  metal detector and mine sweeper of sorts. Once flipped onto this view, however, the one feature that grabs the eye is the impressive mouth. This whole unit can be extended out – about four inches on large individuals – to vacuum up food and gravel (see below). the gravel is expelled out the gills and the food items are crushed between bony plates in the throat.

One of the data points that needs satisfying is to identify the sex of any given fish. Sexing a sturgeon can be easy to do – or it can be hard. It has nothing to do with make-up or barbel curlers but depends more on the season. During the spring breeding period, the males will emit seminal fluid and the females will emit eggs if prompted to do so. Prompting, in this case, consists of a firm but gentle hand massage from the mid-belly down to the vent opening.  Not wanting to change the rating of this site, I elected not to show you the result of a “spermeating male” but I can show you a massage conducted on a female (see here).

This female turned out to be eggless, but the size of the vent hole was a good indicator of her femininity. I did end up seeing some sturgeon eggs before my river season was over, however. That story will have to wait until Part II (I have Seen the Future).

May 9, 2009

An Everyday Miracle

Filed under: Uncategorized — wykes @ 6:59 pm

Miracles really do happen every day. They are a common part of everyday life, although most of them are easy to overlook due to their scale. I’m not talking about changing water into wine or making the Cubs a winning team. No, I’m referring to those multitude of small miraculous happenings such as birth, growth, and transformation. The natural world is full of such events – there for the viewing if you look in the right place at the right time.  The metamorphosis of a salamander nymph into adulthood is one of those tiny transformative miracles.  This is essentially a process in which a fish becomes a land roaming beast (Normally I would say that this is no small feat except it does involve the acquisition of four small feet).

To catch the transformation of the Smallmouth Salamander it’s best to hold them in temporary captivity to observe them as they hatch and grow. In nature, the tiny hatchlings are impossible to find and catch since they hide in the bottom debris of the vernal pools. Once you find some, you need to hold onto them for a while. “My” salamanders began their captivity as eggs (see earlier Naturespeak) and I’ve tracked their development for about a month now. In outward appearance the change has been remarkable.

This miraculous process is driven by pituitary hormones. Each cell reacts differently to the chemical signal. Some of them, for instance, feel the urge to become feet and legs while others answer the call to become lungs.

Upon their initial emergence, they were but simple  swimming heads with feathery gills. The early nymphs are fish-like in all regards, breathing with three pairs of external gills and swimming with the aide of a large tail fin. From the get-go these characters are voracious predators which begin to feed on daphnia, aquatic insects, and even each other if the opportunity presents itself. Fueled by this flow of nutrition, their landward bound process proceeds at a rapid pace. Within a few short days they sprouted a pair of front legs, each endowed with three rudimentary toes (see below). Eventually two more toes accompanied the others to make a grand total of five.

Along with a steady increase in size, from really small to just small, their coloration becomes more diffuse and speckled. If you look closely at these speckles,  you’ll see that some are yellowish and others are dark olive and all are “star-like” in appearance. These spots, especially visible through the thin tail membrane, are pigment cells called chromatophores. By re-distributing the pigments within the cells, the tiny creature can become dark or light – depending upon the mood. We get into dark moods also, but express our feelings in a much different manner.

With the arrival of a set of back legs, about two weeks later, a major internal change is also underway (see below). Those baby lung cells are beginning to get their act together and the nymphs begin to make regular trips to the surface in order to gulp air. The course of the next month will see the gills shrink and disappear as the lungs take over the primary respiration responsibilities. Changing from a gill breather to an air sucker in two months- now that definitely is no small feat!

At present, “my” Smallmouth Salamanders still have very large heads in proportion to the rest of their bodies (see here). These big-headed smallmouths have about a month and a half to go before they complete their miraculous transformation and forsake the water for the mucky land. I will release them back to their native pool before this happens.

Although I won’t be able to witness it, I know their heads will grow proportionally smaller, along with their mouths, and they will forget all that they went through. A 1927 study on metamorphosing salamanders concluded that they actually suffer “memory loss” upon loosing their gills. This is probably a good thing – a salamander is likely to get an attitude if it knows that it is the product of a miracle.

May 5, 2009

Toto, We’re Not in Kansas Anymore

Filed under: Uncategorized — wykes @ 8:48 pm

It wasn’t the first time a White-faced Ibis showed up in S.E. Michigan, but the event was rare enough to cause quite a stir among the birding sort. Needless to say, these sickle-billed things aren’t from around here. They aren’t found in Kansas either, but seeing one there wouldn’t be quite as dramatic since they are usually restricted to places west of the Mississippi River. Sighting any Ibis east of the big Miss is a small, but significant, event. This species generally hangs around the Texas gulf coast -with spotty breeding locations in Utah, California, Nevada, and Idaho. They also inhabit parts well south of the border, but their distribution is difficult to outline.

Any description of the range of the White-faced Ibis is peppered with words like “usually” and “generally” because they seem to be homebodies of a nebulous nature. You’d think they’d stick to a certain range like all the other birds, but nooooooooooo, they have to be all discontinuous and un-dependible like. Apparently, it’s in their nature to be geographically flaky. Their larger breeding colonies tend to disappear from one place and re-appear in another and they have a reputation for finding brand-new habitats, created by temporary floods or over-abundant rains.

Given the above discussion, I guess seeing an Ibis along the shore of Lake Erie shouldn’t be all that surprising. It is tempting , however, to blame the event on the sustained southwestern winds that preceded it’s appearance. It may have been blown off course – forced to take a left at Albuquerque as it were. Forced down onto the wet puddled grass of Lake Erie Metropark  in late April it resumed normal activity as if nothing was wrong. Strong southern winds probably kept it here, but the food situation wasn’t desperate. Everything it needed was to be found here. Seeking it’s normal diet of insects, worms, frogs, and crayfish the bird spent the next week methodically probing the soggy ground with it’s magnificent “decurved” beak (see below). True to form, it vanished from time to time, but became a regular visitor at the picnic area at the south end of the park.

Still, this lone bird looked a bit out of place.  White-faces are gregarious birds.  I watched it for several extended periods and saw that it would stop, stand erect, and look around as if looking for the “rest of the gang.” When it stopped to scratch it’s head with one of it’s long toed feet (see below) it looked even more be-fuddled. The occasional company of a Red-winged blackbird or a Ring-billed Gull did little to alter the situation. Seeing this bronze plumaged bird next to a gull did provide visual confirmation of  it’s small size (only 19 inches long with a wing span around three feet). One can’t help but to be amazed by that steel gray bill either, but I guess I mentioned that already didn’t I.

In all likelihood, my anthropomorphic impressions are just that – plain wrong. Perhaps this bird was a confident explorer among his kind. Perhaps it was deliberately seeking new lands. This is, after all, how species exploit new territories. Perhaps sometime in the future the descendents of this I-bis will not be A-lone alone in the G-lake country. Or, maybe they will!

May 2, 2009

Deep in the Devil’s Lair

Filed under: Uncategorized — wykes @ 9:07 pm

The devil made me do it a couple of years ago and he made me do it again last week. When I last poured Plaster of Paris down a crayfish hole, it was to discover how the burrow was shaped and how deep it went. After digging a hole four foot deep in order to extract the plaster cast, I found out. I ended up with a three foot long contorted replica of a burrow that ended at the water table.

 That should have been it, but, last week I got the urge to pour plaster down another crayfish hole. I guess this is a middle age thing or something. Some guys want to get a red car and others want to pour plaster down a crawdaddy hole every other year. The thought is not as irrational as it sounds. As a naturalist I am “naturally” curious about such things and the literature is inconclusive on such questions. My last effort was unsatisfactory because the crayfish hole was made by a very small crayfish with very little imagination. I’ve noticed over the years that many of the burrows appear to have multiple entrances.

 The Devil Crayfish is a common burrowing crayfish species that lives in moist meadows and grassy places close to the water table. They are aquatic but do not live in ponds or streams. Instead, they dig down into the earth and live secret hidden lives soaking their simple souls within dark ground water tunnels – coming out only at night to feed on dead crap and worms. There appears to be little reason why this particular species is called a Devil Crayfish, because scientifically they are called Cambarus diogenes which refers to a Greek weirdo and not a fallen angel. Diogenes was a 3rd century B.C. hermit of who lived in a tub or large kettle. He was known to walk the streets looking for an honest man. Diogenes carrried a lantern, even though he performed this senseless street duty during the day!

Like Diogenes, burrowing crayfish live their lives inside tubular retreats of their own making. Much of the excavated mud, produced during the excavation process, is piled up around the entrance to create a tower or chimney (see below) although some entrances are “clean.” Though the chimneys are familiar sights, their makers are not. So, I had a sudden desire to see a live “chimney crayfish” and to re-investigate their burrow layout.

I did the deed in the middle of the week. It took a full box of plaster and a half pitcher of water to pour enough slurry down a hole to the point of filling it up.  Two days later, I dug the hardened plaster out. The pieces broke into several pieces and some of the plaster at the bottom failed to properly set, but I ended up with an assemblage of burrow casts (see here) which I was able to re-construct, sans bottom connector, into an exact cast of the channel system (see below and here).

The result is a main tunnel (the tall portion in the middle) which includes the inside of the 8 inch chimney, a branching right hand channel which returns to the surface without a chimney, and a deep descending loop that descends into the water table and then curves back to the surface as another left hand “secret” entrance. The sides of the burrow are irregular and bear the scratching construction marks of the devil his-self.

Much to my delight, I found that I had managed to entomb the crayfish resident of this tunnel system without killing it. It turned out to be a she-self and not a he-self. She had managed to back up into one of the side galleries and was there when I broke open the earth (see below). Apart from having a few chunks of plaster sticking to the hard exoskeleton, she was fine – pissed -but fine. I was able to identify it as one of those Greek hermit crays.

One of the most striking features of this type of crayfish are the red-tipped claws and the red linings between the segments (see top photo). They are astonishingly bug-eyed when compared to other crayfish species – of which there are 400 species in North America. As you can see, I positioned her next to another intact burrow so as to take a few “natural shots” before letting her return to her subterranean element. You can hardly notice the bits of plaster can you?  Really, they don’t look that obvious if you just squint your eyes. 

The she-devil eventually retreated down one of the secret entrances (see below). While there is a definite possibility that she was killed and eaten by the current resident, it is just as likely that she encountered a lonely male who, in stunned silence, praised the crayfish gods (or devils) for his sultry gift. The fact that I did not find any plaster-encrusted crayfish parts outside the burrow entrance the next day may provide evidence that the latter, rather than the former, scenario played itself out! I expect to see lots of little mud chimneys popping up around my yard as a result.

So, there you have it. I have satisfied my biennial plaster-in-the-crayfish hole needs and identified a real burrowing crayfish in the process.  On top of that, I ended up with another cool-looking plaster sculpture to add to my collection. Two years from now, who knows, I might paint the thing red and park it in the garage.

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