reptiles – Page 3

Tuesday Miscellany

The month of July has been one thing after another, it seems, and I’m not just talking about nature observations. Between moving at the start of the month, internet downtime immediately following the move that stretched into a few weeks, unpacking and settling into the new home, housesitting for my parents a couple of times, and a trip back to Halton for a funeral, I’ve had lots of distractions that have kept my mind from blog. As a result, I have a pile of photos that I’ve taken but not posted that I thought I’d gather together and put into a miscellany post.

The first photo is from a couple of weeks ago. I’d taken Raven for a walk at the 100 acres that adjoin our main piece of property, to scout out the trails and get the lay of the land. As I was following the path through a field lined with milkweed, I spotted this little guy curled up in the leaf of one of the milkweed plants. It was a smaller Gray Treefrog than I usually see, and the facial markings were particularly well-defined. I wrote about treefrogs last spring when I found one calling from my parents’ water garden.

Another amphibian, this one an American Toad. This guy turned up at one of our MAPS stations. I’d just taken off my rainpants (which I consider a vital piece of clothing in the early morning hours when everything is still covered in dew) and had sat back down on the rock when I was startled to discover a toad only a couple of inches from where I’d just flopped down. I’d missed squishing him by less than a hand’s breadth. You can read more on toads from a post I did last fall.

Another near miss, this Eastern Milksnake was sunning itself on a patch of moss when I very nearly stepped on it. It may even have been the same day. I haven’t seen too many milksnakes about; even though they’re common, they’re not frequently encountered, being less numerous I guess than the abundant garter snakes. I’ve done a post on milksnakes, too. It happens to be my number one top most visited post that I’ve written so far, no doubt because they are often kept as pets.

I found this caterpillar in the grass at Rock Ridge a couple of visits ago. It stayed in the same spot for half the morning. It was a fairly chunky caterpillar, as these things go, and being brightly coloured I figured it would be easy to look up when I got home. I searched through all of my caterpillar references, and then did a Google image search for yellow caterpillars, and wasn’t able to find it. So I turned to my usual fallback, BugGuide.net. Within hours of posting the photo, it was identified for me as an Elm Sawfly – not a lepidoptera at all! Which would explain why it wasn’t in my caterpillar books. (It is actually in the Kaufman insect guide, but looks white there, not yellow, so I may not have noticed it). Sawflies are actually a type of stingless wasp that deposit their eggs in the twigs or leaves of plants. The “saw” in their name refers to the structure of the ovipositor, which resembles a saw.

This one really is a caterpillar. I believe that it’s a species of moth in the genus Furcula. However, when you look at caterpillar guides or online at BugGuide.net, all of the Furcula caterpillars are green with brownish saddle patches. None are completely brown. A Google image search turned up only one other brown Furcula caterpillar, which was taken by Bev of Burning Silo, who happened to have taken the photo just up the road (relatively speaking) from mine.

I found this nifty fly resting on a dried flower head among the patch of sunflowers when I was searching for insects. It didn’t move when I plucked the deadhead and twisted it around for a better photo. I wondered if it might be dead or possibly parasitized, but when I put the stem back down and it brushed against a leaf the fly took off. It’s a Tachinid fly, possibly in the genus Cylindromyia. Tachinid flies are nearly all internal parasitoids of caterpillars and other insects. Whereas parasites will feed off their host but let them live, parasitoids nearly always kill their host in the end. You can really see well the “halteres”, the vestiges of the second set of wings, which look like round knobs behind the main wings here.

In banding you often have the opportunity to see some strange things you may not have noticed or been able to observe while the bird was perched up in a tree. This is one of those things. This bird’s foot has been infected with a type of bird pox that gets under the scales of the foot and causes mutated growth of the cells. This one is an especially “hairy” looking one, many just grow thick and lumpy. These growths are especially tender and prone to bleeding if they get caught up in netting or the like, and you can just imagine how uncomfortable they must be for the poor birds. I let this guy go as soon as I’d removed him from the net, without taking him back for processing. Occasionally the pox can spread up their leg, and if it does it can become a nasty situation, causing the normally loose bracelet-like band to squeeze and constrict the leg. Some birds will never suffer that, but better safe than sorry.

The new home has many bluebird boxes scattered out in the meadows behind the house. When I was walking through the meadows near one of these last week I could hear constant chittering coming from one of the boxes. As I drew nearer, I could see faces frequently popping up to the hole to peek out at the world. Clearly these were fledglings that would be departing the nest either later that day or the next. They had lots to say, and weren’t too concerned about me. however, when Raven came near to the box, panting loudly and conspicuously, they all shut up and sat tight. Too late, little birdies, you’ve already given away your location!

And finally, this box belonged to some actual bluebirds. Dan discovered the nest, tipped off by a couple of upset adults when he walked by the general vicinity of one of the boxes. Very young, only a few days old at most, these babies are most likely a second brood for the bluebirds. Baby birds grow fast to begin with, but second broods are especially fast, and these babies were probably out of the nest by a week and a half old, two at the most. The boxes that are currently in place are old, weathered, and some are starting to rot. Also, they all require a screwdriver to open. Dan and I will probably replace a few over the winter/spring with new ones that can just be flipped open to check and clean. They’re all currently above head height, too – hard to see what’s inside without a stepstool! I got this photo by holding the camera above my head and hoping for the best.

Scheduled post: Turtle crossing

June seems to be when the turtles come out. In the last few weeks, Dan and I have moved probably dozens of turtles off of the road and out of harm’s way. Around here, the landscape is so rocky that sandy roadsides are incredibly appealing to turtles as potential nest sites. We’ve seen a good mix of species along the roads. The Snapping Turtles whose eggs I wrote about earlier are one of the more common species, although I’ve seen fewer adults than I have depredated nests.

This individual was along the shoulder while I was doing my point count route. On my way back, after I’d finished the counts, she had moved out into the middle of the road, so I stopped the car and shooed her back into the ditch. She was moderate in size, her shell perhaps a foot long, although very old individuals can get nearly twice this big. Most turtles sort of drag themselves along, shell to ground, but as I nudged her with my toe, she lifted herself off the ground and hurried across the road in a peculiar, stilt-legged gait. Note the sharp “beak” in the first photo. Snapping Turtles are omnivorous, but favour protein, and will eat mostly anything they can catch including vertebrates such as fish and ducklings. They have powerful, crushing jaws, and can do some damage to well-intentioned fingers – hence why I moved her by prodding her with my toe.

The other species we’ve seen a lot of is Map Turtles. These guys superficially resemble Painted Turtles from a distance, being about the same size and general shape, and with yellow markings along their necks and legs. However, when you get closer you can see that their shell has a ridge running down the backbone, and they lack any red in their patterning. Supposedly the name Map comes from the pattern of swirly-cues on their shell, which to some people resembles maps of watercourses or topography. They’re a locally common species occurring in a patchy range from Minnesota, east to Vermont, and south to Georgia. In Ontario and Canada it’s a Species of Special Concern due to recent declines caused primarily through habitat loss.

I’m not sure why this one was so sandy, although there was a sand pit a short distance down the road and I wondered whether she’d been in there to lay her eggs, although they’re supposed to prefer sites within 50m of the water. They come out on warm evenings or humid mornings from late May through July, and lay 10-15 eggs in a shallow nest dug by the female. Interestingly, while the eggs of the Snapping Turtle are perfectly round and resemble ping-pong balls, those of the Map Turtle are elliptical, longer along one axis. Along their longest dimension they average about 1.25 inches, or 3.3 cm.

Nature’s artwork

Yesterday afternoon I’d put Raven out on her tie-out in the yard, and was sitting inside at my computer doing some work. Raven will occasionally bark at random things if she’s feeling bored – a stray flowerpot, a broom propped against the house, other things that I can’t see. She’s got a particular type of bark that goes with those objects, playful. But yesterday she started barking something different, very much alarmed and uncertain, something she almost never does. So I went out to investigate.

I noticed some movement in the long grass at the edge of the lawn, which I took at first to be a snake, so I returned inside to get my camera. When I approached closer, to take a photo, I realized it wasn’t a snake, after all, but rather a turtle. I reached in and pulled it out of the grass for a better look. It was a Painted Turtle, Chrysemys picta, and a good-sized one with a shell 15cm (6″) long.

I presume that she was wandering about looking for a sandy spot to lay her eggs, since this is about the time of year they would be doing so. If that were the case, then this would be a female turtle. The females don’t reach sexual maturity until at least 5 years of age, sometimes not until 7 or even older, while males are ready to mate at 2-3 years. That’s a long time to have to avoid predators and cars. Dan thought he saw another one in the side yard near where the soil was recently disturbed to have the septic tank pumped last week. That’d be a great spot for a turtle to lay eggs, so I’ll have to check for any signs of digging. The nests are only about 10-12cm (4-5″) deep, and the female lays only a relatively modest 4-15 eggs. However, she may build up to five nests in a season.

There are two ways to determine the sex of the turtle. One is by the placement of the cloaca on the underside of the tail. In females, the cloaca is close to the body, while in males it’s further down the tail. This confirms this individual as a female. Also, the shape of the shell above the tail is helpful: in females it’s relatively straight, while in males it’s notched above the tail. The reason for both of these differences has to do with how turtles mate. Sex in plated body armour is not easy, and takes a bit of careful manoeuvering. The male climbs onto the back of the female with his forefeet so that his tail is approximately aligned with the female’s, and then curves his tail underneath so their cloacas meet. The notch is so that when his shell is tipped backwards it’s not cutting into his tail.

Even the tail gets tucked away when the turtle pulls itself into its shell. Really, when they “retract” their body it isn’t all that different from you pulling your knees and arms to your chest to form a tight ball, except that the turtle has a wide, hard shell overhanging on each side. A turtle’s shell is actually modified bone; the back is modified ribs, broadened and flattened to form a continuous surface, and the the belly is modified sternum. The turtle’s backbone is fused to the interior of the shell, so unlike a hermit crab that can trade in its shell if it finds something it likes better, a turtle is very much connected to its shell for life. If you find an old shell, its owner long since gone, it’s interesting to examine the bone structure.

Look at those claws! Turtles have remarkably long, strong claws that are used for a number of purposes. Defense, certainly, if needed, but a turtle’s primary defense is its shell. The claws are more useful in helping to grip the ground to power forward when walking on land – a cumbersome endeavour – as well as in digging out the nest site. However, males have substantially longer claws than females. Wikipedia suggests he uses them in foreplay to “tickle the cheeks of the female rapidly up-and-down in a vibratory manner”. I don’t know if this is true or not, but… whatever gets you going.

From underneath you can really see the colours that give the Painted Turtle its name. There are four subspecies of Painted Turtle, all varying in the alignment of their shell scutes and the patterns on their faces. We have the Midland Painted Turtle (C. p. marginata) here. The Western Painted Turtle (C. p. bellii) is also found in Ontario, but only in the northwest, near the Manitoba border.

Turtles hibernate over the winter, burying themselves in up to 3 ft (90 cm) of mud under relatively shallow water. In this environment they are starved for oxygen, but have evolved the ability to survive for up to five months without oxygen at temperatures just above freezing. This is the longest known period of oxygen deprivation of any air-breathing vertebrate. Unsurprisingly, over the winter their metabolism slows to a near crawl, but unlike the Wood Frog, they don’t “die”.

One can often see Painted Turtles in the summer hauled out of the water on a submerged log or rock. They do this to sunbathe, to raise their body temperature since, as reptiles, they are unable to thermoregulate themselves. Their body temperature needs to be at least 65 F (18 C) in order for them to digest their food properly. Interestingly, Painted Turtles, as well as other semi-aquatic turtle species, will only eat underwater.

Raven remained freaked out by the turtle even when I showed her it was harmless. Probably a good thing for any future turtles she may encounter, anyway. I picked the turtle up and took it down to the lake to release it, where it would be away from Raven (both for its sake and Raven’s). I set it gently in the water at the edge, where it remained momentarily, before abruptly extending its limbs and motoring away into the lake. For all their awkwardness on land, turtles are really at home in the water, moving swiftly and with ease. In the blink of an eye, it was gone, hopefully off to find itself a better nesting site than our driveway.

Today at Kingsford – Snapping Turtle eggs

The home inspection associated with the sale of the house was scheduled for yesterday morning, so I bundled Raven up and headed over to the nearby town to see if I could find any cardboard boxes to get started on packing. I also made a stop at the local ball diamond to let Raven run for a bit – something that this house lacks is open space for her to dash around. There’s a little side yard, but it’s just not enough space for Rocket Dog. We had a nice outing, Raven got lots of exercise, I got a few wine boxes from the liquor store, though the other stores’ recycling pickup had unfortunately been the day before, so I wasn’t able to get any large boxes.

On the return trip home I decided to go along a back route that I don’t normally take because it’s narrow and twisty and indirect. It’s significantly faster to go along the main route, but the back route is quite scenic. Since I wanted to give them lots of time to finish up the inspection before I returned home, I opted for the slower, scenic route. As I was coming along a section that ran alongside a lake, I spotted what appeared to be a mess of white reptile eggs at the side of the road. I quickly pulled over and stopped the car, grabbed my camera and asked Raven to stay patient for a couple of minutes, and went over to investigate.

There were a lot of them, and they were strewn across the sandy shoulder. As I got closer, I could see that there was a small hole in the ground that presumably they had once been inside of. And as I got closer still, the mound of dirt beside the hole suggested that these weren’t simply a natural hatching. Inside the hole there were still a couple of eggs, but it appeared that nearly all of them were now on the ground at the side of the road.

The eggs were large, nearly the size of a ping-pong ball, and about the same texture and hardness. Based simply on the size, I figured they had to be Snapping Turtle eggs. There are certainly snappers in the area around here, although I haven’t encountered too many. They don’t haul up on logs the way Painted and other small turtles do, so it’s easier to miss them. Snappers lay their eggs in sandy soil, usually in June although in some parts of their range they may lay eggs spring through fall. The eggs get covered up in the sand, and heat released from the ground as it’s baked by the sun over the summer helps to incubate the eggs. The young eventually hatch after about 100 days, in August or September. When they hatch, the babies are just 4.4 cm (1.75 inches) long. They crawl up through the soft sand, and then make their way to water.

That is, if they manage to survive undiscovered for the entire summer. Reptile eggs are a delicacy for foxes and raccoons, and many clutches will end up as somebody’s dinner. The difficulty the female turtle faces, when she lays her eggs, is in concealing the nest sufficiently that it doesn’t arouse suspicion before the next rain can wash away both visual and olfactory clues to its presence.

The rain didn’t come soon enough for this nest. Not a single egg was intact. Most of them were clean inside, but there were one or two that looked like they contained what might have been egg yolk. I suspect raccoon, which would be more likely to hold the eggshell and lick the interior clean of yolk. Also, the hole in the ground was way too small and tidy to be the work of a fox (consider what results when your dog digs up your garden, for instance), but for a raccoon with dexterous arms and hands it wouldn’t be any trouble to dig a small opening and then reach inside to pull out the treats.

A female snapper may make more than one nest, each containing anywhere from 20-40 eggs, so hopefully she has another clutch safely buried somewhere, but it’s entirely possible this was her only bunch and she’ll have to wait till next year to try again. Fortunately, wild snappers, once they’ve made it through those perilous first few years, may live up to 30 years or more – captive individuals have been recorded as old as 47 – so she should have many opportunities for a successful clutch.

Today at Kingsford – Black Rat Snake(s?)

Our landlord was up at the house today to take care of some yard work, so for Raven’s daily exercise I clipped on her leash and headed up the road. I haven’t been doing that as much since the forest has leafed out and all the birds have returned, since there’s only so much exercise I can give her through walking on a leash, but today I decided to walk down the next road to the neighbouring lake, where I could toss a stick in for her a few times.

It turned out to be a fortuitous decision, because just as we were starting down the last hill before reaching the lake, we discovered this beauty of a Black Rat Snake sunning on the road. At least four feet long, and a good inch and a half thick, it was the largest rat snake I’ve seen so far (admittedly, this is not a difficult accomplishment, as I could count the total number I’ve seen on one hand).

More than other snakes I encounter here in the woods of southern Ontario, Black Rat Snakes have that predatory look to their eye, that fierce glance that one sees in the faces of other carnivores such as hawks and wolves.

Look at the longitudinal muscles running along the sides of his spine – you can see them flexed where his “neck” curves. Snakes are practically all muscle, strong, used to help the creature move across the ground in the absence of legs (and, in the case of some, to suffocate and kill prey in the absence of claws).

By complete coincidence, a few hundred yards beyond the rat snake we discovered this old snake carcass lying at the side of the road. At first I thought it was a shed skin, but as I drew closer I could see the bones sticking out from the dried flesh. I’m not sure of the cause of death; it could have been a roadkill that has been picked over by scavengers and dried out in the sun, or it may be a hawk kill, quite possible the meal of one of the Red-shouldered Hawks in the area. I’m leaning toward the latter, mostly because the head and the tail remained intact, although I must admit I don’t know whether hawks just tear the flesh off of snakes, or if they eat them whole, but in bits.

Check out all those ribs. I’m surprised they’re still as intact as they are. The average vertebrate – you, your dog, the robin on your lawn – has a dozen or two pairs of ribs (the number varies by species; humans have 12 pairs, dogs have 13, horses have 18) attached to the thoracic vertebrae of the back, along with cervical (neck), lumbar (lower back) and caudal (tail) vertebrae that make up the rest of the spine. In snakes, the number of cervical, lumbar and caudal vertebrae are reduced, and the number of thoracic vertebrae greatly increased – some of the longest snakes may have upwards of 300 thoracic vertebrae, each with a pair of ribs attached. One particular gene complex, called the Hox genes, controls which type of vertebrae each segment becomes, depending on which ones are switched on in which segment. They also are involved in the development (or lack thereof) of legs.

I’d planned to do a bit more poking around the ‘net for more information on the eating habits of hawks, and developmental biology of snakes, but we seem to have exceeded our download limit for the day (we’re on satellite internet, which has the disadvantage of having a bandwidth quota), and the connection is reduced to slower-than-dialup speed, so the questions will have to wait for another day.