Category Archives: mammals

Big Brown Bat

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I’ve been doing that thing again where I get distracted by other projects and forget to post here. Sorry about that. It’s been a busy month and promises to be a busy month to come.

Here’s something from a few weeks ago. One morning Dan discovered this guy (or gal?) on the screened-in porch. I believe it’s a Little Brown Bat Big Brown Bat (thank you to PFG to Mammals author Fiona Reid for correcting my ID!), one of the most common around here; we’ve got a colony of these (whichever species they are) that occasionally take up residence in the cracks of the beams above our front (open-air) porch. They’ll stay for a few days then move to a different roost for a while. We always know when they’re there because the porch beneath becomes littered with bat droppings.

Dan propped open the door hoping the bat would let itself out while he took care of some chores inside, but when he returned a while later it had settled down on some trim up near the ceiling and fallen asleep. I’ve heard that you’re not supposed to move bats during the day, and since it wasn’t at risk of bothering anyone there we decided to leave it till evening. It stayed put, barely moving, till dusk.

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As the sun started to set it began to shift. It crawled over the edge of the trim and hung there, tucked into the corner, still looking very sleepy. I decided that was my cue to shift him outside; we’d let the cats come out while the bat was asleep (they’d remained completely oblivious) but once it showed signs of waking up I didn’t want to take any chances.

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I donned gloves and got a kitchen towel to collect it up in. Unfortunately, in my concern about injuring it my grip wasn’t firm enough and it slipped out. Still dozy, it basically glided to the floor where it sprawled with its wings out. What a neat opportunity to see the intricate structure of the wings and tail. And look at those tiny toes on the back feet! They and the thumb, at the “wrist” of both wings, are long and thin and designed for clinging to stuff since the bat doesn’t really have the option of using its hands. Still, it’s more than birds have.

Those wing bones are incredibly thin and delicate. Birds, of course, have evolved to have hollow bones that helps to reduce the amount of weight they need to get airborne. Bats don’t have hollow bones so they just have to be smaller in the heavy bits. It also helps, however, that the long finger bones allow bats to make shapes with their wings that other flying creatures (birds and insects) can’t – they use this for producing novel mechanisms for increasing lift, to compensate for their greater weight.

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Bats are amazing creatures, really. Besides just the flying, they’ve got the really cool ability to echolocate, something shared only with some cetaceans, a couple species of birds, and a type of shrew. (Only certain types of bats echolocate, however – microchiropteran bats, the nocturnal insectivores; flying foxes, the fruit bats, don’t.)

Those big ears are important for catching the sound as it bounces back. It’s a complex skill involving the measurement of time between making the sound and hearing the echo, the time between hearing the echo in one ear versus the other, and the intensity of the sound for one ear versus the other. This is mostly done instinctively, below the level of consciousness. We do some of this ourselves already, in being able to identify from which direction a sound has come from. The only difference is that the bats are listening for echoes of sounds they produced themselves.

Remarkably, it’s possible for some blind or visually challenged people to develop a form of echolocation to help them navigate their world. Their visual cortex is repurposed for processing sounds instead of sights. The YouTube video above (also here) is an amazing example.

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The bat climbed up onto my glove easily once it was on the floor, and I took it and tacked it up to the side of the house (a convenient advantage of wooden logs). It still seemed sleepy and not ready to head out yet, so I left it; when I checked back half an hour later, it had gone.

Bear encounter

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Yesterday afternoon while heading out with the dogs to see if I could relocate a Common Buckeye butterfly that Dan had seen in our back fields (they don’t typically occur up here, so this was a really rare sighting), we startled some wildlife in the tiny patch of trees that the trail passes, no more than a couple dozen feet across and a few dozen feet long but dense enough at the edges to make it hard to see into. The dogs were, of course, intensely interested and my focus was on preventing their pursuit of the thing; so it didn’t immediately register that the sound of departure was not the bounding ba-dump, ba-dump of alarmed deer but something more shuffling. Then when I seemed to hear something climbing a tree I thought it must be a porcupine, which I also did not want the dogs taking off after. But when I got Jack secured and Raven to heel and peered through the foliage, what was looking back at me was not a porcupine. Or a deer.

I was too surprised to move, at first. But the bear seemed more cautious than aggressive, and after a moment I relaxed, a little; enough to pull out my camera and try for a few shots. She was tucked in behind a wall of vegetation through which I had just a small window to see her, but I got a couple of photos that were recognizably of a bear and was content with that. Carrying Jack, and with a firm verbal leash on Raven, I turned and carried on down the trail so she could leave.

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I made my way slowly to the field where Dan had seen the butterfly and dawdled around there for a bit (didn’t find it). Then I started to mosey back, pausing a couple of times to take photos of things. By the time we returned to the woods patch the bear had had lots of time to clear out, but I still picked Jack up and approached slowly, just in case. Cautiously I peered through the trees to the spot she’d been, but the patch was empty and silent.

Relieved, I set Jack down. She’d made some marks on the trunk that I wanted to check out, so I started picking my way through the trees toward where she’d been. Halfway there, when I was about twenty-five feet from the target tree, there was a soft grunting growl and the bear sat up on her haunches beside it.

Panic! Panic! Call the dogs back! Jack, come! Raven, heel! Now! Thankfully, both dogs came quickly, and I turned my shoulder to her to show her I was not trying to threaten her (even while keeping her in my sight, just in case!) and started to casually leave the forest patch. She didn’t say another word as she sat back and watched me, alert and uncertain but staying her ground. I paused near the edge of the trees, since she wasn’t moving, and took a couple more (quick!) photos without the obstruction of leafy vegetation, then left.

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A couple of times while I was nearby she tried to climb the tree she was beside. This is about as high as she made it before slipping back down to the ground each time. When I’d first glimpsed her, through the small window in the vegetation, I’d thought I’d seen a second little head beside her. I’d definitely heard more than one animal in there, startled by our approach. And given the fact that fifteen minutes later she was still sitting beside the same tree, and inclined to climb it, even, I’m guessing she had at least one cub somewhere up that trunk. (I didn’t think to check, at the time; my focus was more on containing the dogs.)

It wouldn’t surprise me if that were the case. Last fall I found evidence that was very suggestive of a mother bear with a cub. Female bears mate every other year, and take two years to raise each cub. If the second animal of last year’s discovery was in fact a bear cub, it’s possible it was a second-year cub that was weaned before the winter, and this is the same mother bear with a new baby. Female bears tend to have home ranges of 1600 to 6400 acres (2.5 to 10 square miles; which is about 6.5 to 26 square kilometers); certainly not small, but not so large that the same animal wouldn’t pass through an area semi-regularly, especially if she had favourite haunts.

It was exciting to finally get a chance to glimpse our local bear, since in the three years we’ve been here we’ve seen lots of evidence of their presence but no actual bears. I kind of wish it had been at more of a distance… but hey. Luckily, she was calm. It makes me happy to know she’s out there, somewhere, and passing through from time to time.

Cats / tracks

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I’ve been waiting for a really nice, sunny, mild day to head out with my cordless drill to clean out our nestboxes, and the weather conditions were perfect for it this afternoon. I took photos and will follow up on that on probably Wednesday.

While I was out there, though, I saw a number of other critters enjoying the sunshine like I was. I spotted a few fuzzy caterpillars, mostly Woolly Bears like the above. They emerge so early, I don’t actually know if they spend any time eating before they pupate. There wouldn’t be a whole lot to eat yet. Although, I did spend some time raking out our garden, and the first shoots of daffodils and croci are coming up, as is the rhubarb. And quite a number of plants stay evergreen under the snow. So maybe there would be enough.

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On the way back to the house I came across this guy, who I initially mistook from a distance to be another Woolly Bear, but who turned out, upon closer inspection, to be a Giant Leopard Moth caterpillar. I still get inordinately pleased whenever I discover one of these guys, even though they’re not uncommon here. We didn’t have them where I grew up (or if we did, I never noticed them); it wasn’t till I moved east that I started seeing them. So I still get that thrill of somethingcool! when I find one.

As I was walking back from the last nestbox I noticed a robin off some distance away in the forest, making a lot of noise in the leaf litter. I’d brought my binoculars with me (something I don’t always do, since I do most of my birding by ear these days and it’s one less thing to carry around) so I was able to watch him closely. After a moment or two he picked something up, dark and thick and C-shaped, carried it a short distance, then plunked it down in the leaf litter. I’m fairly certain it was a dark fuzzy caterpillar like one of the two above. I think he might have been trying to de-bristle it prior to eating it.

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I made a brief detour out to the rail trail and walked down to the creek, and discovered these tracks out there. What first caught my eye was the size of them. Certainly much bigger than any deer I’d seen around here. They’re cloven like deer and domesticated ungulates (except horses/donkeys), but there was really only one animal I thought could make something that large, at least that I would reasonably expect might be found walking down the rail trail. Which is a moose, of course.

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Having seen a moose in our back fields last fall, this wasn’t quite the stretch that I might have otherwise thought it. It’s possible he’s hung around the area, in one of the swamps nearby, keeping out of sight. I took a few photos and double-checked my tracks guide when I got back. They seem to be potentially confusable with domestic cows, with the main distinguishing feature being the front of the track – the hooves are pointed in moose, but rounded in cows.

You can’t see it as well in the first photo, but you can tell in the second that the front of the tracks are pointed. It was pretty clear in person, too, that the paired hooves were long and tapering at the front. They were relatively fresh… I didn’t notice them on my way out, only on my way back, though that’s not to say that they weren’t there and I just missed them on the way out. I tried following them to see where they went, but they seem to curve out from the fenceline and then back into the fenceline. I can only presume he jumped the fence, then got spooked after walking only a short distance down the trail and jumped back. And yes, moose, like all deer, can jump:

Who Knew? - Moose Jumping a Fence Photo by Bruce Barrett (nordicshutter) on Flickr; CC-licensed (the only such photo I found of a moose jumping, though there are others that are not CC)

Otter trails

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A couple of weeks ago I noticed these trails out on the ice of the creek the rail trail crosses. It looked like the animals had traveled down the frozen stream on a mild day, or perhaps just after a rain, when the snow that had been sitting on top of the ice had softened just enough to create slushy conditions. The temperature must have dropped shortly after because the prints, while not detailed, were certainly well-defined.

When I first noticed them I’d naturally not brought my camera along, but the unusually dry winter we’re having did me a favour and didn’t snow at all before I was able to make it out. (It’s snowed since, but not very much, and you can still pick out the tracks frozen into the ice. I worry a bit for what this will mean for spring water levels, unless nature’s saving it all up for March. In which case, I worry for March.)

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The tracks belong to otters, of course. I say “of course”, but I actually wouldn’t have known this prior to moving to the lake house a few years ago. Then, we discovered a set of similar tracks out on the ice of the lake, and I’d hypothesized that it was a predator periodically dragging a heavy prey. Which still seems like a reasonable guess, but the real answer is obvious, now that I know it.

The long troughs are from the animals sliding on their bellies. They’ll bound for several strides and then flop down, letting their momentum and the slippery ice carry them forward. This helps conserve energy – and during winter, every little bit counts – but is also probably just darn fun. As animals go, otters must be among the most playful.

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I’ve actually seen otters in this creek before, so I’m not too surprised to see their tracks here, but I tend to forget they’re around. I encounter them much less frequently here than I do down in the Frontenacs where Dan and I do our summer bird programs.

The Atlas of the Mammals of Ontario, a project undertaken by Ontario Nature and published in 1994 (back when they were still known as the Federation of Ontario Naturalists), provides range maps for all of Ontario’s mammals. The larger species are typically more well-documented than the smaller ones (rodents, bats) simply because they’re easier to find and identify. All of the maps are available at Ontario Nature’s website.

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I’ve included here the range map for River Otter, as documented up through the early 1990s. White squares indicate areas where the precise location the record is from (mostly historical and/or OMNR trapline data) can’t be pinpointed. Coloured squares are known. The data used was taken across most of the last century, when available, with date indicated by shape.

It’s pretty clear that the otter shows a close correlation to the Canadian Shield, rarely found in the limestone regions of most of southern Ontario. This is probably partly due to the fact that water bodies become scarcer in regions with the more porous limestone bedrock, but also likely has something to do with human land use. We’ve modified the vast majority of Ontario south of the Shield, to either urban or agricultural landscapes, with all the loss of habitat and pollution that comes with both. The Shield itself is too rocky, with too shallow a soil base, to make for good farming, so it’s largely been abandoned to nature in the last several decades. Where we live still sees a fair bit of agriculture, but it’s all mostly low-impact – small-scale livestock and hay farms. In the Frontenacs, even that scale of farming becomes scarce, and the primary use of land is simply residential and recreational – homes and cottages.

I was so delighted when I discovered, via a neighbour at the lake, that there were otters in the area. And then when I found the tracks – and later, saw the animals themselves – I was over the moon. Otters! How cool! I’d always thought it funny that I’d never seen them where I grew up, and had kind of figured it was just because where I lived there weren’t any decent-sized water bodies. But looking at the map, now, I guess they weren’t in the area at all. Even if all I’m seeing are the tracks, it’s nice to know they’re here.

Flying Squirrel

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I missed last week’s post, busy preparing for a wedding, and yesterday, catching up from the wedding; apologies! But I’m super excited about today’s post. I was planning on another topic for this evening, actually – I’ll end up doing it this weekend, perhaps. But as I came down to check on the fire I noticed Oliver was hunched over, peering out the window at something at the window feeder. He does this regularly, and always when I go over to look there’s nothing there.

But this time there was! A small, furry brown body was curled up right at the window’s edge, its back to the house. I thought at first it was a rat or mouse, but then it stretched out to grab a seed and I got a good look at its eyes. They were huge! This was no rat – it was a flying squirrel!

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I knew we had flying squirrels around here because I’d found shredded cedar bark in one of the nestboxes a couple of years ago. The box actually wasn’t that far from the house, but I’d never seen evidence of them visiting the feeders (on the other hand, I don’t know exactly what I’d be looking for). I have, however, on occasion heard little feet scampering up the side of our log house while I’ve been working in my study late at night. I know that sound from the daylight hours when the Red Squirrels run up and down to the feeder. I guessed that the nighttime scamperings must therefore belong to flying squirrels – but I’d never seen one till tonight. Here or otherwise.

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There are only the two species of flying squirrel in North America (though there are a few subspecies). Ours are most likely Northern Flying Squirrels, though we’re near the northern edge for Southern Flying Squirrel, too. There are visual differences between the two species if you get a good look at one, including size, but they’re most readily distinguished by habitat preference, with the Northern preferring mixed or coniferous forests and the Southern largely mature hardwood forests, especially Carolinian. Our forests around here are pretty strongly mixed.

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The flap of skin between the front and back legs can only be easily viewed when the squirrel is gliding, of course, though you can sometimes see the wrinkle there when they’re still. They’ve also got flattened tails that presumably help with steering when they’re in the air, and oversized eyes to help see in the dark. They’ve got a varied diet and are pretty opportunistic about what they eat, but Wikipedia suggests the bulk of their diet is truffles (various types of underground fungi), which they sniff out with their nose.

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Obviously, they also eat birdseed. We have our feeder set up so one side of it is butted up against the house, below the living room window. The cats and Jack love this. Jack’s mostly interested in the Red Squirrels, while the cats prefer the birds. The critters at the feeder learn pretty quickly that what’s going on behind the glass has nothing to do with them and they’re free to keep eating. All of our animals will paw at the window or press their faces right up to it, but it doesn’t bother the critters at the feeder in the least.

Apparently the flying squirrel has learned this, too. It sat not four inches from Oliver’s nose, just a couple panes of glass between it and some sharp teeth. But it was very confident in those panes of glass. Charlie came and joined us after a bit (the two of them made it a little hard to get any pictures). I could put the camera right up to the window, the lens knocking against the glass and the flash going off at regular intervals, and the squirrel would be completely undisturbed. It’s too bad there’s a screen in the window; it makes it hard to get good shots. The smeary nose prints all over the glass doesn’t help, either. ;)

I hope he’s a regular visitor! I think it’s so cool we’ve got a flying squirrel coming to our feeders.