Tuesday, March 29, 2011

Boardman River Nature Center

Steph and I have been in Traverse City for the past few days, and we decided we'd take a look at the Boardman River Nature Center. It's a relatively new building, situated in the Grand Traverse Conservation District, and it's one of the nicest nature centers that I have had the pleasure of visiting. Neither Steph nor I had been there before, and we were pleasantly surprised by the wide variety of child-friendly hands-on activities and displays, some of which had an emphasis on art.

The nature center's taxidermy was all museum-quality, and was some of the nicest I've seen. What I found to be most interesting was that very few of the mounted animals were behind glass, and many were accessible -- pelts and skulls accompanied the mounts, and could be touched. Because the taxidermy was of such good quality, and because most mounts were supplemented with information about the animal, very few live animals were in captivity at the nature center -- another plus, in my book.

Fish of Michigan I

One of the central displays was a collection of freshwater fish mounts, showcasing the fish of the Great Lakes. Pictured here: a burbot and a crappie.

Turkey/Loon

A wild turkey and a common loon -- one is hunted, the other is conserved. I think both birds are pretty neat in their own ways!

River Otter Marten

Mustelidae -- the minks, martens, otters, and ermines. I thought the river otter mount looked quite noble and dignified. Accompanying it was also a (very long) pelt, as well as a skull.

Snowy Owl

A worried-looking snowy owl, one of the few mounts that was behind glass.

Taxidermy is a wonderful teaching tool, as are other animal remains: antlers, bones, turtle shells, and fur scraps were available for handling and close examination. The children who were at the center seemed to be extremely excited to see the animal mounts (especially the bear); one child pointed to a fawn behind glass and said, "Look at the pretend deer!"

Related, I recently checked out a book, Are Those Animals Real?, at the library. It explains how museum taxidermy mounts are made, and their value to education and science. The book is a good, short read for children and adults alike, and I learned a few things!

Wednesday, March 23, 2011

Taking Shelter in the Dead

As the weather warms and the snow melts away, tiny creatures that hibernate during the long winter months crawl out from their hiding places. How do such small, fragile beings survive the cold temperatures and harsh conditions? Some invertebrates tuck themselves away beneath fallen leaves and tree bark, and others overwinter, metamorphosing inside woolen cocoons. Other arthropods are more inventive, as I found out on a Vernal Equinox walk through the Matthaei Botanical Gardens property.

I encountered the remains of several deer, including this doe skull. It was resting in the middle of a field, with no other bones nearby; the long exposure to the sun had bleached the skull a bright white, unmistakable in a sea of brown grass. I turned the skull over -- and what did I see?

Doe Skull III

A tiny millipede -- the first of several I saw that day, all using bones as their shelter. I made sure to turn the doe skull back to its original position; I have no doubt there were many other creatures living inside.

Nearby, I found the bones of another deer, this time a buck whose antlers had long-since been removed. While most of the skeleton was relatively intact and more or less articulated, the skull and a few of the leg bones had been scattered further away. I turned one of the leg bones to see what I could find; not only was there a strange cocoon wedged into a hollow of the bone, but also two velvet mites milling around on the surface of the cocoon.

Velvet Mites I

Velvet Mites II

Velvet mites are something I don't see very often, but when I do, I'm always happy to watch their behavior. They're quite large (for mites), so it's pretty easy to observe them. I'm not sure what the mites were up to, but judging by their different sizes, I'm guessing it was a male and female, the female being the larger of the two. They interacted for a while, touching legs and scurrying about.

The last find of the afternoon had far better camouflage than the bright-red velvet mites:

Daddy Long-legs

This daddy long-legs (order Opiliones, also known as harvestmen) was squeezed into a furrow of this woodchuck skull, looking a lot like the nearby dirt and other organic matter.

It has become obvious to me that bones, especially skulls, are very important to insects, arachnids, and other terrestrial arthropods. Not only are dead animals a source of food, but they provide shelter, as well. During the cold, snowy, and icy months of a Michigan winter, skeletons become instrumental in keeping our invertebrates safe and dry.

See also -- Bone Home, June 23 2010.

Sunday, March 20, 2011

A Hawk in the Courtyard

Hawks are a common sight in our neighborhood. Sometimes, they are seen being mobbed by crows, and other days, they are predators, swooping down on mourning doves and sparrows. The two species most often seen where Steph and I live are sharp-shinned hawks and Coopers hawks; sharp-shinned hawks are quite small -- no larger than a crow -- but won't hesitate to take down mourning doves and pigeons.

A few days ago, we actually witnessed a sharp-shinned hawk swoop at a flying mourning dove -- there was an audible whump -- and miss. As feathers floated away, the hawk sat on the branch of a pine tree, probably wondering where to hunt next. The courtyard, usually so loud with birdsong, was absolutely silent, and the hawk departed.

The day after, as Steph and I walked through the courtyard, finding feathers left over from the previous day's near-miss, I spotted something else: the body of a sharp-shinned hawk, resting beneath a tree. At first, I worried that it was the same hawk we had seen the day before, but we soon realized the corpse was far older. The bird's eyes were dry and had sunken into their sockets, meaning that the body had been lying there for quite some time.

March Sharp-Shinned Hawk I

March Sharp-Shinned Hawk II

We're not sure how the hawk died. The body wasn't near any windows, though it's quite possible the bird struck a window and was subsequently thrown beneath a tree, away from an apartment. Perhaps the hawk was mobbed and killed by crows; its feathers were quite rough in some places, though no blood was visible. Perhaps it was sick or old, and, roosting in a tree, it passed away.

This sharp-shinned hawk was a challenge to photograph; its proportions were small, but being a bird of prey, it was still quite majestic, a duality that was hard to portray.

Thursday, March 17, 2011

Twins

Yesterday, I got a call. A doe had been hit and killed by a car, and it was discovered that she had been pregnant. Not one, but two fetuses were found inside of her; both males, they were small, mostly hairless, and pink. Their ears were folded behind their heads, their hooves were rubbery and soft, and the only pigment to be seen was the black on their noses. I was struck by the fetuses' fragility and strange peacefulness, and their almost translucent nature. Knowing that this was something one does not usually have the chance to see, I took a series of photographs. I hope these views convey the same sense of both wonder and melancholy for you, the reader, as the fetuses did for me, in person.

Twin Deer Fetuses

Deer Fetus

Twin Deer Fetuses

Deer Fetus

Tuesday, March 15, 2011

Useless Creature Triple Feature

I've got a trio of animals to discuss, the first of which is March Buck. The day after the body was found and the head was removed, I transferred it from my parents' garage to their backyard. An amazing amount of blood -- almost a cup's worth -- had dripped out from the neck overnight. I took a few photographs of the buck's head; a bit of blood had fallen near the still-intact eye, staining the fur, and looking for all the world like a teardrop.

March Buck VIII

The next step was to cover the antlers in aluminum foil, in an attempt to discourage squirrels and mice from chewing on them. A a result, the buck looks a lot like a macabre Christmas decoration. I tied the head to the fence, to keep any scavengers from taking off with it, and that was that. Over the next few days, I returned to check up on the head, but as of Sunday, there really wasn't too much to report.

Yesterday, I returned to visit the rest of the body. On the way, I encountered an old deer skull that had long ago had its back half (and likely antlers) sawed off; the mice have since used it as a source of calcium. When I finally reached the site of the dead buck, I was amazed to find that the (very heavy) body had been dragged between twenty to thirty feet from its original place! I have no doubt that this was done by coyotes; indeed, they had truly ripped into the carcass, taking advantage of where we had sawed off the buck's head. The skin on the neck stump had been peeled back, and the coyotes had stripped the muscle from the remaining neck vertebrae. Parts of the ribcage were also exposed, and the shoulder blade was no longer inside the skin. It's probably reasonable to assume that the next thing that will happen -- if it hasn't already occurred -- will be the scattering of the deer's limbs.

Here is the view from the cedar tree, where the dead buck was first found:

March Buck

As I drove out, I noticed a dead opossum on the side of the road, near the gardens' entrance, but I decided I'd come back for it later. That afternoon, Steph and I did return, with the intention of simply moving the opossum from the ever-busy Dixboro Road to a more sheltered place. It was a bit more of a trickier operation than I'd bargained for, and it involved crossing a stream and getting whacked in the face by many a thorny branch. I finally reached the opossum, waited (quite a while) for traffic to pass, and grabbed the tail, disappearing back into the underbrush.

The opossum was a huge male, and very heavy. His skull was split, and a tire tread had ripped open his belly. He had a faint, musky smell, the tip of his tail had succumbed to frostbite, and his feet were absolutely fascinating.

March Opossum

March Opossum

It was so interesting to be able to view this opossum's feet up-close. The whorls on the paw pads looked a lot like human fingerprints, and the front foot even felt a bit like a human hand. Opossums have such specialized feet for climbing and gripping branches; the "thumb" on the back foot was a bit of a surprise!

March Opossum

Like many roadkill opossums I've encountered, this individual's mouth was wide open, exposing his very sharp and numerous teeth. One canine had been crushed when he'd been hit, but the rest were present. Opossums have a pretty bad reputation, and I'm guessing it has a lot to do with their naked, rat-like tails and their pointy, seemingly endless number of teeth. They're North America's only marsupial, and they've gradually moved north into Michigan. Opossums didn't originally live in such cold areas, and their naked toes and tails often suffer because of this northern migration.

We left the opossum's body near the bank of the stream; it will decompose in a more dignified place, and it will be scavenged in a far safer area.

As we studied the many animal tracks in the mud near the water -- we identified raccoon, muskrat, and mink prints -- a flash of white caught my eye. It was another raccoon skull poking up through the leaf litter, not far from where I'd found the raccoon skeleton on Thursday.

Raccoon Skull

We found many bones, resting both atop the leaves and in the dirt. This was another young animal; the ribs were tiny and the vertebrae were not fully fused. As we drove home, Steph made a discovery that was at first alarming -- something was inside the braincase! I feared the worst, thinking it was a spider egg case, but whatever it was seemed far too woolly and hairy to belong to a spider. We decided it was probably a moth cocoon, and a quick internet search matched exactly with what is inside the skull. Right now, we're keeping the raccoon skull inside a bugbox, with the hope that the tussock moth will emerge.

I hope to follow up on this interesting re-purpose, and will definitely take some photographs. What a neat use for a skull!

Thursday, March 10, 2011

The Buck Beneath the Cedar Tree

It's been a very snowy winter -- one of the snowiest on record in Ann Arbor, in fact. Several times, the snow has melted, revealing the earth, and several times, it has snowed again, only to cover everything up once more. March is a month of flux; today, the snow was melting, and tonight, the snow will likely be falling. This morning, I headed outside to see if the newly-uncovered ground revealed any dead animals or shed antlers.

I followed several deer trails, through marsh and field, and poked around beneath coniferous trees. One of the first things I found was a spot where a rabbit had been consumed: soggy fur and entrails littered the slushy snow, and crow footprints led to and from the scene. On the muddy bank of a stream, I discovered some fantastic examples of raccoon footprints, and a few yards away, I found the skeleton of a raccoon:

Raccoon Signs II

Most of the bones were under the leaf litter. The skeleton belonged to a rather young individual, as the sutures on the skull had not yet fused, and some of the bones (mostly the vertebrae and leg bones) had not completely fused, either. This is the third raccoon skeleton I've found since moving to Ann Arbor, and the second I've found at the Matthaei Botanical Gardens.

The real find of the day, though, came about thirty minutes later. I was slogging through a field, my feet cold and wet, when I saw a turkey vulture take to the sky. It had been eating something, and I knew I had to investigate. As I drew closer, and the vulture circled overhead, I saw one antler, and then another -- it was a dead buck, resting beneath a lone cedar.

March Buck V

It took me a while to decide how old the body was. At first, I thought the death was rather recent, but the buck's hindquarters had decomposed quite a bit. At the same time, the front half of the deer -- especially the head -- was in remarkably fresh condition. One eye had been pecked out, likely by the vulture, but the other eye was intact. I finally came to the conclusion that the buck's body, at least most of it, had been buried beneath the snow for some time, and was only recently revealed in the latest melt.

The first thing I noted was that the buck had seven tines on his set of antlers, and one of them, the right eye guard, had been damaged at some point, either during the rut or while he was still in velvet. In addition, his antlers were much whiter than I'm used to seeing.

March Buck II

The second thing I noticed was far more mysterious and worrisome. On the buck's left foot, stuck between his hooves and dewclaws, was a thick, plastic band. It was hard to look at: the skin and bone had grown around it, resulting in a misshapen, malformed foot, and his hooves had grown long and deformed as a result of the injury.

March Buck III

It's obvious that this buck had been in a lot of pain. I have to wonder how much this injury hampered his movement, and if it got infected. Perhaps this led to his death; I can't imagine a limping deer would fare too well in deep snow. I can only assume that early on in this buck's life, he stepped into the tube, and it never came off.

The buck was certainly a challenge to photograph. Though it was in good condition, his face was not very dignified looking, and the rest of his body was in the process of being picked at by vultures. As a result, I focused on his antlers: they were stately, proud, and more or less permanent, unlike his fur and muscle.

March Buck VI

After I finished photographing the deer, my mother joined me with a couple of saws and a lopper. It took an amazing amount of sawing -- and now I understand what the scavenging vultures and crows are up against! -- but my mother was finally able to break through the fur, skin, muscle, and bone. Like September Squirrel, I will observe the decomposition of this buck's head in my parents' backyard. It will be interesting to note the differences in both the scavengers and speed of decay in comparison to the rest of the body, which I will check up on periodically, as well.

We also cut the plastic band from the buck's foot; I will keep that, too, as a reminder of what happens when garbage is discarded so carelessly.

Saturday, March 5, 2011

Rainy

Today, I took a walk in the rain. I encountered two partially-eaten mice; both, I am sure, were killed by one of the many feral cats that live on the Matthaei Botanical Gardens' property. What's left will likely be dinner for a crow or other carrion-eater.

March Mouse

Wednesday, March 2, 2011

Gnawing Away

It's a fact: rodents love to gnaw. One of the most notorious gnawing critters, at least in the north, is the porcupine; I have heard stories of them gnawing on just about anything, and that includes outhouses. Here in Ann Arbor, there sure aren't any porcupines, but there are fox squirrels, and a whole lot of them. The squirrels are especially prevalent in our neighborhood, and our birdfeeders suffer because of it. Still, I can't help but have a soft spot for these crafty, acrobatic rodents -- they're smart, they're cute, and they're fun to watch.

Last October, during one of our many forays onto the property of the Matthaei Botanical Gardens, we found the tibia of a deer. Before winter arrived, I left the leg bone out on the deck of our apartment, in the hope that the local fox squirrels would find it tasty and useful. They discovered it almost immediately, and soon were chewing away! It's amazing just how loud the sound of gnawing can be.

Today, I was finally able to photograph a squirrel in the act of gnawing. In just a few minutes, it had made quite a dent in the bone.

Calcium

Here's a view of the tibia, after this most recent gnawing:


Squirrels gnaw on bones for a couple of reasons. Firstly, bones are full of calcium and other minerals, nutrients that rodents need to survive. Shed deer antlers are also a favorite of porcupines, mice, and squirrels.

Secondly, the incisors of rodents grow for as long as the animal is alive, and gnawing keeps them worn down to a manageable length. If a rodent's teeth aren't used on a regular basis, the animal will undoubtedly develop life-threatening dental problems. I have seen gruesome images of squirrels and other rodents with incisors that have curled and grown through their skull. Gnawing on bones, as well as nuts, antlers, and plant matter, keeps rodent incisors healthy.

Interestingly enough, bone-gnawing is as old as the dinosaurs, as this article reports.

Sociable