A little after noon I spotted the first-of-the-season Northern Water Snake coiled up under a Baldcypress at the bottom of the boardwalk in the Wetlands.

Although not necessarily known as even tempered snakes, Northern Water Snakes are harmless.

The same day, Lead Animal Keeper Kristen spied a Copperhead along the path in Explore the Wild.

And today, Lead Horticulturists Joe found several Rough Earth Snakes (Virginia striatula) and a Brown Snake (Storeria dekayi) under some debri at one of the Museum’s storage areas. Both of these snakes are small snakes, maxing out at about 13 inches and 18 inches respectively.

One of several Rough Earth Snakes seen on the 11th of March.

Brown Snake.

Close-up of head of the Brown Snake.

Brown Snakes are gentle little snakes, please respect them by leaving them be if you come across one on the trail.

March 10 was also a busy day for turtles. Besides the dozens of Painted and Yellow-bellied Turtles out basking, the first Common Snapping Turtle of the season was seen from the Wetlands Overlook.

The turtles were stacked up on the Wetlands (3/10/10). Pictured here are all Yellow-bellied Turtles (sliders).

I wonder what will show up today?

The same day, Spring Peepers, Upland Chorus Frogs, (The chorus frogs are the ones that sound like someone running their finger down a comb, the peepers are the higher pitched single notes heard) Pickerel Frogs, and at least one (1) American Toad was heard calling from the Wetlands or in the swamp between Catch the Wind and Explore the Wild.

A Pickerel Frog readies for the mating season.

Still no snakes. Still no odes (dragonflies/damselflies).

The snakes could very well be up, but just not out and about. It’s the odes that have me troubled. I’ve usually seen Fragile Forktails by this time each year. The only explanation I can think of as to why I haven’t seen them yet has to be the unusually cold February that we’ve had this year (by North Carolina standards). Any day now, any day.

And finally, what’s that? What are Lead Horticulturist Joe and Facilities Tech Craig looking at?

Is that a bird they're looking at?

No…

A big blue blimp went over yesterday afternoon.

It’s a blimp!

Keep looking up, you never know what’s going to sail by.

One of a group of some dozen Fish Crows passing overhead (and calling) on Saturday (3/6/10).

Though Fish Crows have been seen and heard in our area (Piedmont) for several weeks, Saturday (3/6) was the first sighting for me at the Museum. If I hadn’t heard them first I would have passed them off as American Crows. Although Fish Crows are a bit smaller the two species look very much alike. Luckily, their calls are a bit different. Fish Crows sound like an American Crow with its nose pinched as it calls, it’s very nasal.

It’s very difficult to gauge the bird’s size in flight, but sometimes you can distinguish the two by size alone or by the cadence of their wing-beat , but I wouldn’t bank on either.

Most Fish Crows leave our area in winter so it’s a sort of spring right-of-passage to see them each year at this time, one of the undeniable signs that spring is upon us.

As far as the Leps, Saturday also brought out a few butterflies. A Questionmark, American Snout and Mourning Cloak were seen.

Enjoy.

Elm buds have been showing for a few weeks, this one was close enough to the ground to photograph.

Red Maple is in full bloom.

Wax Myrtle is showing buds.

A Gray Squirrel partakes in a tasty snack of buds or flowers, or both.

A Carolina Chickadee inspects a natural cavity in a sycamore. This tree is within 12 feet or so of the boardwalk. If the bird decides to use this for nesting it may make for good photographic opportunities.

A Red-winged Blackbird checks out the Wetlands. This bird was in the company of three others and was just passing through. There is, however, alone male who sings daily in the Wetlands.

Apparently always excavating holes in trees at this time of year, a Brown-headed Nuthatch continues its work.

I noticed this bird circling above Catch the Wind (2/5) performing a "courtship" flight. I later found the bird (Cooper's Hawk) in a pine calling loudly kak, kak, kak, kak...it's time to think about nesting.

A winter resident at the Museum, this Ruby-crowned Kinglet searches for food among the branches of a willow in the Wetlands. Kinglets often start singing before leaving us for points north, I haven't heard their song yet.

Get outdoors and have a look around for yourself, and let me know what you see!

American Sycamore

I was recently asked whether or not I knew why the bark on American Sycamore drops off the tree in large thin flakes. Coincidentally, while walking around the Outdoor Exhibits this winter with camera in hand, I’ve been taking photos of various trees to use on this blog in a series of informal, mini-field guides. My intention was to start with some of the more readily identifiable winter trees, trees without leaves. Although winter’s nearly over, this is a good time to squeeze in at least one of those mini-guides.

One of the easiest of trees to identify is the American Sycamore. It’s white upper bark standing off against the winter sky, and other trees in the forest, make it hard to miss and appreciate.

Sycamore is a tree of the bottomlands. Just about any stream or river in our area has it’s share of sycamores growing along its banks, often alongside River Birch. Here at the Museum it grows next to the Wetlands as well as in the swamp between Catch the Wind and Explore the Wild. This handsome tree is often planted along city streets but its roots are near the water.

Many trees have a different type of bark at the base of the trunk than they do at the younger, upper portion of the tree. The sycamore takes this to the extreme.

Take a look at the tree on the right. Scroll up and follow the bark up to the top. It starts out as “typical” gray bark. As you scroll up you’ll notice that the darker bark begins to flake off until finally it becomes nearly all white at the top of the tree.

Towards the middle of the three, starting at about a quarter to a third-way up the tree, the bark often appears “camouflaged” with various gray, brown, and green hues.

Below are some close-ups of the bark.

The lower portion of the trunk has rough gray-brown bark.

The bark becomes scaly and flakes off about 1/4 the way up the trunk. It often appears as if camouflaged.

Towards the top of mature trees the bark may be nearly all white.

But, why do sycamores shed their bark? Why does the bark peel off in large thin flakes all season long? I’ve sometimes wondered that myself, but apparently not long or hard enough to actually find out…until now.

Trees have bark to help protect them from losing moisture and drying out, protect themselves from insects (although there are many insects that get past this defense), birds (woodpeckers go in after the insects), and disease. And, all trees have bark specific to the trees themselves. Flowering Dogwood has scaly “alligator” bark. Loblolly Pine has furrowed, segmented bark which bares a resemblance to the loblollies on a dried lake bed. Shagbark Hickory has a shaggy appearance with big, gray pieces of bark sticking out from the trunk. Sycamore has bark that peels off and becomes white near the upper portion of the tree.

What evolutionary advantage is it for a tree to shed it’s bark the way sycamores do? Everything from the tree’s favored habitat to photosynthesis has been suggested by people who should know, people who study trees. Most of the theories that I’ve read seem like sound reasons for this bark shedding habit. Apparently though, there is no definitive answer to the question of why this tree looks and behaves the way it does.

Instead of me quoting or paraphrasing the various suggested answers to this question, from another source, it may be easier for you to read them yourself. The linked article is from the Daily Plant out of NYC, NY and tries to answer the question of why sycamore sheds its bark through an interview with Dr. Marc Abrams, Professor of Forest Ecology at Penn State University.

Oh yeah, back to the identification of the tree. If the bark doesn’t nail down the ID of this tree for you, perhaps the many fruit balls that typically dangle from the branches will do it.

Sycamore has fruit balls on its branches all winter.

The fruit hang from the tree throughout the winter, are about an inch to an inch and a quarter in diameter and, unlike the spiky seed balls of Sweetgum, are soft to the touch.

On your next walk through Explore the Wild stop at the platform midway down the boardwalk. If you stand facing the Animal Footprints Exhibit and look about 40 degrees or so to your left you’ll see an excellent example of an American Sycamore with all of the features described above. Another is about the same amount of degrees to your right. If you look about 90 degrees to your right you’ll see a slim, straight sycamore which is nearly all green, all the way to the crown. Why is this sycamore green and not white? That one will have to wait for another day, maybe.

Enjoy your walk.

]]> http://blogs.ncmls.org/greg-dodge/2010/03/03/the-big-white-tree-with-the-peeling-bark/feed/ 3 http://blogs.ncmls.org/greg-dodge/2010/02/26/red-tails-red-breasts-and-a-nervous-nomo/ http://blogs.ncmls.org/greg-dodge/2010/02/26/red-tails-red-breasts-and-a-nervous-nomo/#comments Sat, 27 Feb 2010 00:03:37 +0000 Greg Dodge, Ranger http://blogs.ncmls.org/greg-dodge/?p=4224 As a follow-up to the Spring? posting of February 25th regarding the questions on the Red-tailed Hawks:

A few hours after posting the above, I was out in Catch the Wind and observed a pair of Red-tailed Hawks performing their aerial courtship flight. I didn’t get the whole sequence of events on film (digital), and the birds were way up there requiring a bit of enlargement, but hopefully you’ll get the gist of what the birds are doing.

One bird (on right) comes in from above the other bird, which is slowly gliding into the wind

The upper bird lowers its talons and drops in closer.

It's just about at this point where the lower bird inverts itself with talons raised, the two locking talons and tumbling through the air.

The next image should show the birds tumbling through the air, but unfortunately the birds went behind a group of tall pines and we’ll have to wait till next time for that one. Sorry.

Later the same day, down on the ground, a group of some fifty American Robins were feasting on worms and other invertebrates.

Some of the robins that have stopped in to rest and feed on their journeys north.

A closer view of one of these very familiar, handsome thrushes.

Although our avian visitors were eating invertebrates at the time, American Robins relish berries and other small fruit. Northern Mockingbirds (NOMOs), who also like fruit, and who stake out and protect winter territories where their food source is plentiful, get rather anxious when a group of fruit eating birds settles in nearby.

This Northern Mockingbird appears a bit bothered by all of the robins that decided to stop and feed in its territory next to the Ornithopter.

See you outside!

Sure, it was colder than usual the first two months of this year. And, it seems as though it has snowed more this year than within memory. It’s predicted to snow today!

A recent snow in the Wetlands.

But, there’s much evidence pointing to a new season springing forth. The days are getting longer. Both the maples and elms are ready to burst open their buds and Hazel Alder is nearly in full flower.

Elm buds, swollen and ready to bring forth flowers.

The sun is coming up earlier and setting later. Chorus Frogs and Spring Peepers are calling and Pickerel Frogs have been seen slowly moving about the landscape. More and more turtles are coming out to bask in the afternoon sun, both Yellow-bellied Sliders and Painted Turtles.

Two Yellow-bellied and one Painted Turtle come out to bask in the afternoon sun.

I saw a solitary wasp in a sunny spot of the trail in Catch the Wind and a paper wasp flew by me in the Wetlands.

On my drive in to the Museum recently I saw two different Red-tailed Hawks carrying nesting material. The two Brown-headed Nuthatches that were digging a hole in a Loblolly Pine in Catch the Wind at the beginning of this month are at it again, this time on the opposite side of the same tree.

A Brown-headed Nuthatch digs yet another hole in a pine branch. Apparently the first hole didn't meet the standards of its prospective mate.

Listen for the nuthatch’s squeaky-toy calls in the pines as you walk around throughout the outdoor areas of the Museum.

Northern Cardinals have been singing for the past month and, according to Exhibits Tech David, one was seen carrying nesting material last week. I heard the first singing Red-winged Blackbird of the season on the 19th of February. Tufted Titmice are singing their clear-whistled, repetitive notes. Pine Warblers are in song. And, I heard a Song Sparrow briefly trying out its repertoire of rolling trills.

A small band of some two dozen Cedar Waxwings attempted to storm the small hollies next to the Ornithopter for their berries. The Leonardo da Vinci inspired ride in Catch the Wind was too much for the little waxwings; its huge white wings flapping back and forth next to the hollies kept the birds at bay.

A Cedar Waxwing patiently waits for the Ornithopter's wings to stop before alighting on the holly bushes below. Note the red markings on the bird's wing, like tiny drops of red wax.

These waxwings arrived four days earlier than last year’s nomadic troop of over 400 that descended on the hollies growing next to the main Museum Building.

Purple Martins have been observed within our borders. These birds are early arrivals, for sure, but the rest of their species is definitely on its way north.

From this point on things will move quickly. New arrivals from the south will appear, fresh new leaves will begin to emerge, snakes, insects…I can’t wait!

Gray Fox track (front foot) in mud.

Gray Fox are seen here at the Museum throughout the year. I sometimes see their tracks in the mud on service roads and there is a den in the woods near the Dinosaur Trail.

Gray Fox den, somewhere in the woods at the Museum.

The frequency of sightings usually picks up in mid-winter. Over the past few weeks there have been numerous sightings by myself, Museum Staff, and Museum Guests….

It was near closing time on Saturday (2/13) as I stood at the entrance to the Dinosaur Trail looking in the direction of Catch the Wind. A Gray Fox bounded across the trail several hundred feet down the trail where the service road enters the paved path. A few seconds later it bounded across the trail in the other direction. Some thirty seconds later the fox came running up the middle of the path from Grayson’s Cafe and directly in front me as I watched in amazement (and wished that my camera wasn’t still in its case).

The fox continued down the trail until in got to the point where I had originally seen it bounding back and forth across the path. It suddenly stopped, stood for a second, and then leaped into the woods. I knew that Museum guests were still walking back in from Catch the Wind, so I reasoned that the fox had seen someone coming up the path and had jumped into the woods, and indeed, that was the case. I asked the person who was walking up the trail if she had seen the fox and she excitedly exclaimed that yes, she had seen it, as well as another at the Bird Feeder Exhibit (Flying Birds) and, that it (seeing the fox) was the highlight of her day.

The activity became a frenzy on February 17th when a fox was heard calling from the woods near the Red Wolf Enclosure. I later watched as a fox ran back and forth in the woods behind the Cafe calling out as it went along. As I watched this yelping fox search the woods for whatever it was looking for, another called from behind me.

Throughout the day, and throughout the Outdoor Exhibits, Gray Fox were seen by whoever ventured out into the wild. Two fox were seen chasing each other about in Catch the Wind. Two were heard calling at the same time behind the Cafe. One fox was seen leaving the property through an open gate. A fox was seen running down the hill under the boardwalk. A fox was seen at the Bird Feeders. Heard enough?

The next day, I saw one Gray Fox. The following day, no sightings.

What caused this “Fox Frenzy” on the 17th of February? Well, it IS the breeding season for fox. Gray Fox are certainly more active during the daylight hours at this time of year. However, the calling, running, chasing, and timing of sightings on that particular day leads me to believe that there was a third fox on the scene. I can’t say for certain, but perhaps an interloper, another male fox, entered the area seeking a mate. It’s only speculation of course, since I can not distinguish the male from the female and I have not yet become familiar enough with the fox that live here at the Museum to separate one individual from another, male or female, but it seems as if the hyperactivity of the day was caused by a third individual. Any ideas from you, the reader, are welcomed.

To hear what a fox sounds like click on this link. But first, once at the linked site you’ll have many choices of both Gray and Red Fox sounds to sample (our fox are Gray Fox – Urocyon cinereoargenteus). The sounds that are representative of what I heard on February 17 are call.wav and fox territory call.wav.

Oh yes, if you happen to see a fox trotting by, sitting in the woods, or under the bird feeders, look, but don’t approach it. While they are very “cute” and may sometimes appear to be rather “tame,” it’s important to remember that they are wild animals and should be respected as such.

Enjoy!

The Fossil Dig Site signage.

If, before entering, you happen to read the signage at the Fossil Dig Site on the Dinosaur Trail, you will discover that the material through which you are about to search for fossils is of the coastal plain and not of the Piedmont. The gray, coarse material in the Dig Site was shipped in from a phosphate mine near Aurora, NC and at one time was on the bottom of the ocean when that part of North Carolina was under water.

If you stop and read the sign at the Fossil Dig Site you will also learn that the material in the Dig Site was deposited on the ocean floor during a period of about 5 to 23 million years ago.

Some of the 5 to 23 million year old fossils you will likely find at the Dig Site.

What you will not learn from the sign is that the boulders that surround the site, and that are also found along the pathways and exhibits of the Dinosaur Trail, Explore the Wild, and Catch the Wind, are some 200 million years older than the “dirt” in the Dig Site.

The boulders surrounding the Dig Site are much older and of different origin than the fossil material.

That same ancient rock also makes up the rock “walls” that you pass as you descend the boardwalk into Explore the Wild and which forms a natural barrier around half of the Black Bear Enclosure.

Rock wall along one side of the boardwalk leading to the Wetlands.

Durham, NC lies in what is called a Triassic basin, the Deep River basin to be exact (the Durham Sub-basin of the Deep River basin to be even more exact). When the continental plates which comprise what is now North America and Africa began to move apart some 220 million years ago (during the Triassic Period – two geologic periods before the dinosaurs depicted on the Dino Trail were trotting about the landscape), rifts or cracks began to appear in the earth’s crust with at least one of the rifts widening enough to become an ocean basin, the Atlantic Ocean basin. The other rifts, and there are many along the eastern seaboard, became lesser basins filling with silt, clay and other sediment brought in by rivers and streams from the higher ground of the surrounding areas. Over time, those sediments became layered, sedimentary rock.

The boulders, rocks, and rock walls that you see at the Museum are igneous rock, which means that they cooled and solidified from molten rock. This molten rock, or magma, intruded between layers of the already existing sedimentary rock in the Durham Sub-basin, which makes this rock intrusive igneous rock. And, because it flowed between the layers of the sedimentary rock, the formation is referred to as an intrusive sill.

When molten rock lying below the surface (magma) cools deep within the earth the magma cools slowly allowing crystals more time to form and so are larger and visible to the naked eye. You can see the grain in the rock.

When molten rock flowing above ground (lava) cools and solidifies on the surface it cools at a relatively quick rate. Crystals have less time to form and so are small and often not visible to the naked eye. You can not see the grain in the resulting rock without magnification (not to confuse you more, but rock that cools above ground is called extrusive igneous rock since the molten rock, or lava, extruded from the ground).

The rock here at the Museum cooled very close to the surface (but still below the surface) and so is intermediate between the two. The grains in the rock are visible, but are small. It is fine grained rock and, this particular rock, is referred to as basaltic diabase.

The grain, although small, is visible in this close up of the rock at the Museum.

The Wetlands and floor of the bear enclosure make up the bottom of a quarry that was in operation in the early 1930’s and which supplied the local area with crushed rock to surface its roads. If you stand at the Black Bear Overlook and look at the rock face to your left (where the A/V kiosk and scent displays are) you can see vertical lines in the rock.

The vertical lines in the rock are the remnants of holes drilled down into the rock by quarry workers in order to insert explosives for blasting the rock away from the face of the cliff.

The arrows point to the drillings which allowed the workers to insert explosives for blasting away the rock.

Throughout the outdoor areas of the Museum you’ll notice much of the rock is stained various shades of green, brown, orange, and black, among other hues. These colors are on the surface only. The true color of the rock is gray, about 50% gray or darker.

This boulder which sits alongside the Parasaurolophus on the Dinosaur Trail gives a fair representation of the true color of the rock.

If you’re now thoroughly confused, don’t worry, for some of us it’s not an easy thing to learn, this geology. It was quite a while before I actually understood (I think I understand) what all this rock lying about the Museum grounds is, why it’s here, and why it’s different from rock in other parts of North Carolina.

If you want to learn more about the rock formation here at the Museum, and many other geologically important and interesting areas of the Carolinas, I suggest that you read Exploring the Geology of the Carolinas, it certainly helped me to understand some of what I look at everyday as I make the rounds on the paths and trails at the Museum.

One of the authors of Exploring the Geology of the Carolinas, Mary-Russell Roberson, used to work here at the Museum. I didn’t know her but, quite by coincidence, I’m sitting in the office she occupied as I write this.

Geology is something that can be studied and enjoyed in all seasons; the rocks don’t migrate, loose their leaves, or hibernate. Stop by the Museum and have a look for yourself, I promise you that the rocks will be here, and be easy to locate, when you arrive.

Turkey Vultures are a daily sight as they soar, dip and bank across the Museum’s airspace.

Note the small head, gray flight feathers, and rather long tail on this Turkey Vulture sailing over the Museum.

The slightly smaller Black Vulture, while seen at least once a week here at the Museum, is not as often encountered as the Turkey Vulture.

A short tail, small head, and white or gray primaries (the feathers at the tip of the wings) are trademarks of the Black Vulture. Black Vultures flap their wings more often, and more rapidly, than do their larger relatives, Turkey Vultures.

Hardly a day passes without seeing or hearing a Red-shouldered Hawk at the Museum. They are most often encountered while they’re perched in the woods silently watching below for prey.

A Red-shouldered Hawk sits quietly in the swamp between Catch the Wind and Explore the Wild.

Red-tailed Hawks are seen above at least once a week in winter, but there is a two month period during summer when they may not be seen at all. Whenever they do show up, a Red-shouldered Hawk is often there to greet and escort them out of the airspace.

Although larger and more powerful than Red-shouldered Hawks, Red-tailed Hawks are often chased out of the Museum's airspace by the smaller hawk.

This Cooper's Hawk was seen January 28th hunting over Catch the Wind.

Copper’s Hawks have successfully nested here at the Museum for the past two years. I see one of these brazen, bushwhacking, aerial hunters nearly every week of the year, certainly every month. Last week was a double; I saw one (most likely the same hawk) on two different days. Each time, the hawk was hunting from above, settling down into the pines north of the Lemur House.

On February 3rd, a tap-tap-tap-taping sound high in a Loblolly Pine in Catch the Wind signaled the workings of a Brown-headed Nuthatch excavating a nest hole. A pair of these tiny pine dwelling nuthatches had dug two holes in a pine not fifty feet from this location last year, only to give it up (or lose it) to a pair of Carolina Chickadees several weeks later.

One nuthatch quickly exits the hole as the other waits to inspect his handywork.

This pair seems to be a bit ahead of themselves. Last year’s nuthatches were first spotted on February 20 as they had just begun excavation. From the apparent depth of the current hole it appears as though they’ve been working on this one for several days, if not more.

I’ll keep you posted on their progress.