March 2009 – Page 4 – Seabrooke Leckie

Robin on the lawn

Today we had snow. I had really been enjoying the mild weather, but of course it is still early March, and the balmy temperatures can’t last. We have a month of ups and downs ahead of us before we settle into mostly springtime weather (and even then, we still have the possibility of snow right into May). There’s an inch of the white stuff on our lawn now, after it started falling yesterday evening and finally tapered off this morning.

But yesterday, the lawn was bare but for a few randomly-scattered patches of crusty snow. As I was in the kitchen making myself some tea after coming in from our hike with Raven yesterday, I glanced out the window and noticed some movement on the open ground: a robin, scouting for invertebrates groggy and sluggish from the warming sun. And then another, a short distance away. And a third. And finally a fourth, kicking around the detritus on the forest floor.

It’s hard to know for certain if these are migrants, returning with the first signs of spring. Some robins do spend the winter in our frozen north, feeding on icy berries over the cold months, while invertebrates are hard to find. They tend to move about in moderate-sized groups; I noticed a group of about 14 once or twice in our general area over the winter. Others will fly south, some just to the northern states, others might carry on a bit further. Although they’re traditionally thought of as a sign of spring, the bird to watch for, in actuality other migrants such as blackbirds or Killdeer often return before the robins do. I don’t know why robins have come to be associated as a sign of spring – perhaps because by the time they do arrive it’s much more likely that spring is just around the corner? Or perhaps because they are often seen in urban environments, on lawns and in parks, where blackbirds are not.

These were the first ones I’ve seen on our property since the fall. Probably drawn there by the open lawn, since there are no berry bushes on or around our home (if we plan to stay here a while I’ll be sure to plant some, however). Mostly males, with their crisp gray back, jet black head, and rich orange-red belly, although Dan thought he spotted a female amongst the group (which would be more subdued in browner tones). Among migrant robins, males are the first to return in the spring, with females following a week or two later, but both males and females may choose to overwinter in the north. Since these were males, neither possibility can really be ruled out, although it’s still a bit early for migrant females.

I don’t know that the earthworms would be active yet; it was warm, but not that warm, or at least not for long enough to warm the earth up considerably. I noticed most of the robins were checking under the leaves, perhaps for invertebrates that had tucked themselves into crevices in the earth. They would pick the leaves up with their beaks and toss them to one side. They are very proficient at this, able to throw the leaf a good foot or more away. It was slightly overcast by then, and too dark to get a good photo of their leaf-throwing, unfortunately, but you can see to the right of the bird the leaf that he’s just thrown. It was hard to tell just how much they were finding through this effort, but they kept at it.

There was at least one robin who did seem to be hunting for earthworms, or at least wasn’t checking out the leaf litter. Robins on a lawn typically tend to run a number of steps and then pause to cock their head at the ground. While it might look like they’re tipping their ear to listen to what’s going on down there, experiments have shown that robins hunt by sight, not by sound, and the tipping of the head is simply the bird’s way of getting a better view of the ground. Because their eyes are set at the sides of their head, not the front, they don’t have straight-forward vision the way we do, and in order to focus in on a particular object the bird needs to turn its head and look out one eye or the other.

Based on the fresh, crisp wing feathers on this bird, I would guess it to be an adult male (an after-second year in banding terms), meaning that 2009 is at least his third calendar year – he was hatched in 2007 or earlier. Because of the patterns of moult in the different age groups, a second-year bird, hatched last summer, would be showing more wear to its wing feathers, and they would probably also be brownish, slightly faded. In robins the difference can sometimes be quite obvious, particularly as you get closer to summer.

I didn’t notice this till blowing up the photo on the computer, but it looks like when the bird replaced its tail last (which would have been “scheduled” for late last summer, or may have been replaced over the winter if he’d lost some feathers to a close run-in) the waxy sheath that surrounds the feather at its base as it grows wasn’t removed. Most of the time birds will preen these waxy sheaths off, because they start to itch, but it looks like this guy got it halfway off the feather and then forgot about it when it stopped being a problem.

They were gone again today, the robins. There was nowhere for them to forage, the lawn covered up again by the recent snowfall. Off in search of berry bushes, I imagine. But that’s alright, it won’t be too long before they return again – spring is, I’m sure, just around the corner.

Spring in the air

Yesterday was a gorgeous day. So warm that when I took Raven for her walk, I didn’t need my toque – note the bare ears in the photo! And bare hands – no mittens! And unzipped jacket. It was lovely. The day had started out overcast, but by the afternoon the sky had cleared and the sun shone brightly. There was a light breeze, but rather than nipping at your exposed skin like winter breezes usually do, this one caressed your face with soft, warm breaths of air. Oh, it was gorgeous. The sort of day where you just want to close your eyes and soak it in. I took Raven up the road to the abandoned property, where there were a couple of very old wooden chairs tucked at the edge of a clearing in the woods, where I could sit and do just that. The photo just can’t capture how beautiful the day was.

Today was lovely, too. Not quite as warm, so those delicious pockets of warm air weren’t present, but still mild and sunny, with the lingering scent of spring. Dan and I went up the road a little ways to hike around a parcel of crown land that Dan wanted to scout as a potential location for a new MAPS study site (MAPS – which stands for Monitoring Avian Productivity and Survivorship – is a banding program that helps give clues about the “why” to complement the “whether” species are declining that other studies, such as the Breeding Bird Survey, detect; through the use of banding the program helps to determine birth and death rates, as well as other important information on territories and dispersal). We hiked about two kilometers, returning to the Jeep with our feet soaked by the soft, melting snow that still covered much of the woods. But what a splendid afternoon.

The sun and mild temperatures have melted the snow off my small little “garden”, the bit of earth that I cleared and planted with bulbs last October. I planted six types of bulbs: crocus, mini iris, scilla, allium, Nectaroscordum, and fritillaria. The latter three are all late spring bloomers, although the fritillaria might start blooming in late April. The other three, however, are all early spring bloomers. I did plant the bulbs in a particular arrangement last fall, but I can’t remember what went where now. There are shoots poking through the soft dirt already, encouraged by the warm sun and mild weather, but I don’t know who they belong to. I’m looking forward to their blooms!

And finally, the first moth of the season! I was standing outside last night, waiting for Raven to pee. Raven, however, was feeling a little freaked out by the barks of a dog a kilometer or so down the road echoing up the lake. When she gets like that, she won’t pee, despite much coaxing (she does know the command, and under ordinary circumstances will go right out and pee quickly and we can go inside again). So while I stood there waiting for her to gather her courage or whatever she was looking for, a moth flew in and started fluttering around our yard light! I quickly dashed inside to grab my insect net, and snagged it from up on the wall of the house. I suddenly didn’t feel so annoyed with Raven for taking her sweet time.

The moth was a Morrison’s Sallow, Eupsilia morrisoni. They are relatively common and widespread, and among the earliest to emerge in the spring, having spent the winter tucked into some crevice or nook as an adult moth. They will occasionally make appearances during the winter on exceptionally warm days/evenings. Although our temperature made it up to 12 C (54 F) during the day, by the time I was putting everyone to bed at midnight it had dropped to 2 C (36 F) again, and while I thought perhaps the warm sun might have roused somebody from their winter slumber, I had expected any moths to show up would be in the first hour or two after dusk, while it was still somewhat warm. I was quite surprised to see a moth out and about so late, after the temperature had dropped so much. I tucked it in the fridge overnight (it’s actually warmer in the fridge than it was outside, ironically) and took photos and released it this morning, setting it in the sun where it could warm up and then go off to find its own nook to crawl into again.

Today at Kingsford – Vertebrae

On the same outing that I discovered the bobcat scratches, I found a dead tree whose top had broken off, leaving a stump with little pockets where debris had collected between the jagged points. I was reminded of Wanderin’ Weeta’s post where she peered into some holes in the trunk of a tree and discovered, among other things, a sowbug graveyard.

I looked closer at the top of my stump; no sowbug remains, but there did seem to be two little round, white loops that resembled vertebrae. I thought maybe they had belonged to a mouse or some other rodent. I looked around for any other evidence of remains, but saw nothing. To have a closer look, I took a twig and hooked them with it to lift them out. Even my delicate little woman’s fingers were too big and chubby to fit into the small nook.

Sitting them in my palm, it was quickly apparent they weren’t mammal vertebrae. For one thing, the backbones of mammals have a bony bit that sticks out from the middle of the back, onto which the back muscles attach (these are the bumps you see when someone bends over). These little loops had projections to the side. Also, the central holes appeared too large for a mammal vertebra, which has only to accommodate the spinal cord and doesn’t need to be exceptionally wide. I would expect the hole of a mammal’s backbone to be about the same width as the circling bone is thick.

A closer look provides the answer: see the little protrusion at the bottom of the lower one? I believe these are the bleached, empty sections of an invertebrate, possibly a millipede. It’s likely it was somebody’s dinner, and part of the remains were either discarded here or dropped from a perch higher above, and landed in the stump, where they sat and bleached and waited for me to find them.

Shredded bark

While out walking Raven this afternoon, I came across this tree, whose lower trunk had been shredded. It was basically in the middle of the woods, right at the edge of a small clearing. The clearing had a handful of young (maybe 20 years) White Pines along its edge, and two White Spruce of roughly the same age. The photos are of one of the spruces, but the other also had been damaged, less recently. This one looked like it might have been within the last week, perhaps two. There were no signs of tracks in the snow or ground around the base of the tree, no scat, no evidence that anyone or anything had been there at all, aside from the damage to the tree.

The damaged area was only two to three feet (less than a meter) above the ground. At that point the lowest branches started, and there was no access to higher up the trunk. The bark had been absolutely shredded. I might not be surprised at this if it was soft cedar bark or some other soft wood, but the outer layer of the spruce is tough, and the loose bits that hung away from the trunk were stiff. In areas where the bark hadn’t been shredded there was evidence of deep grooves, perhaps as much as two to three millimeters (1/8″ ish) deep. There were a few grooves in the softer wood layer under the shredded area, as well.

What could have done this? My first thought was that it was a buck rubbing his antlers on the trunk of the tree. I might have settled on that and gone on my way if these were cedars, but when I touched the strips of bark and felt how tough and resilient they were, I ruled out deer. They have tough antlers, but they’re not that sharp. I don’t think they would have made the deep, narrow gouges, either. My second thought was bear. There is certainly the odd bear around here, even if I haven’t personally seen one. But bear markings are usually high up the tree, at least at my eye level, if not above. This being less than three feet off the ground, that just didn’t match up either.

My only other thought is possibly bobcat. There are bobcats in the area, as well, though I don’t think they’re very common. Our neighbour up the lake indicated they’d seen feline prints and urine while out hiking in the park once, but the park superintendent couldn’t confirm or deny the presence of the cats.

Bobcats are little, only about twice the size of a housecat, standing 14 to 15 inches (36-38 cm) at the shoulder. They mark their territories in a variety of ways, including conspicuous feces deposits, urine spraying, and clawing prominent trees. Their home ranges can vary considerably in size, depending in part on the quality of the habitat and the number of other cats in the area, but even the smallest ranges are often on the order of dozens of square kilometers (upward of a dozen square miles). This, combined with their secretive habits and tendency to only be out at dawn and dusk, would probably explain why they’re so rarely seen. Also why I’ve never seen one.

The shredded tree trunk seems like a pretty good match for bobcat. The only reason I’m at all hesitant to call it that, besides the fact that I’ve never seen a bobcat, around here or otherwise, and so they exist in the realm of fantastic creatures like unicorns and centaurs, is that I would’ve expected claw marks inflicted by something with a paw to have multiple grooves all parallel to one another, the result of three or four claws being dragged down the trunk together. Instead, the marks here seem to be individual and random. Could it be just that sometimes only one claw pierced the tough bark? On the other hand, this website describes the scratches as being parallel to the tree trunk and two to three feet above the ground – which fits these marks perfectly.

How cool would that be, territory markings of a bobcat? Certainly the closest I’ve ever come to one, even if he is long since gone.

Future potential

Last spring I found a weird clump of insect eggs wrapped around a twig on a small tree at the research station. I discovered what it was while looking for something else on BugGuide.net. It turned out it was a bunch of tent caterpillar eggs. So knowing what they look like, this winter I’ve kept my eyes open to see if I could spot any prior to them setting up shop in their little tents.

Eastern Tent Caterpillars prefer trees in the family Rosaceae. This includes the cherries (Black Cherry, Chokecherry), as well as hawthorn, crabapple and apple trees. Those are the species I most often see their nests on. The closely related Forest Tent Caterpillar opts for oaks and maples. For both species, theirs are the web nests you see in the spring; webs later in the summer and fall belong to another species, usually the Fall Webworm.

I had checked out the apple trees on the property down the road I often vist, but hadn’t noticed any egg clusters. Yesterday I took Raven back there for the first time in ages, since the snow started to melt (before it was quite a trudge in there, with snow up to your shins). Walking down the path I passed by a small sapling with the remains of a nest in it. I’m not sure how I’d managed to miss it on all my previous visits; looking elsewhere, I guess. In any case, I paused here to check for eggs.

I didn’t find any new egg clusters, but I did find what was left of last year’s. I could tell they were old because the eggs were all open, their tops popped off when the little baby caterpillars left last spring. Or possibly even the spring before, I don’t know how long these egg masses last. There were four such clusters on this small little tree – it was evidently hard-hit last year, but spared this year.

A bit further up the path was an older tree, much larger, with a branch that hung down low to eye level beside the path. On said branch was another old nest. Interestingly, this one had some shed caterpillar skins still clinging to it. As the caterpillars grow, they shed their old skins and leave them behind, often trapped in the layers of their web. At the end of the summer you can sometimes find nests with the old skins inside, but I was a bit surprised to still find them there this late in the winter.

It was here on this tree that I found some new egg clusters. They’re very distinctive, with a hard, shiny shellac to them that smooths over the egg surfaces and protects them from the elements. I’m not sure what the shellac is made of, but I presume the little caterpillars have to chew their way out after leaving the eggs. The whole cluster is no more than an inch long (2.5 cm), but wraps nearly completely around the branch. It’s possible for there to be up to 200-300 eggs crammed into that small mass.

This tree had a few egg clusters from last year (obviously, as they would’ve hatched out the inhabitants of the old nest in the tree), as well as the ones from this year. It looked, at least from the ones I found, that there were more eggs this year than last on this tree. On one branch, I found a new egg mass less than an inch from last year’s old one, an interesting juxtaposition of the past and the future.

It’s funny how the tents can take you completely by surprise come spring, like they came out of nowhere. And yet, they were there all along, hidden on the branches in plain sight. I’ll have to remember to watch for these guys when they hatch out and start building their webs in late April.