March 2008 – Page 2 – Seabrooke Leckie

Life and death in a birdhouse

With the nice weather yesterday, and perhaps also as a symbol of the new season, I took my screwdriver and went out to clean out the birdhouses to make room for this year’s residents. When I was growing up we didn’t have birdhouses set up. I’m not sure why, because we always had feeders. Perhaps it just hadn’t occurred to us. Sometime in university I think I won a birdhouse in a bird-related contest that I’ve since forgotten the details of. We put it up that summer, and it wasn’t long before a House Wren set up shop. The burbling song brought such life to the garden – not that the garden hadn’t been lively before, but the wren just added that sparkle.

There’s now five and a half birdhouses out in the garden: four traditional single-unit houses, and a double-unit house. The double-unit is the above covered wagon, which my mom won at a convention or AGM some years ago. By the end of the summer, every single one of these houses has been checked out or used, and they all need cleaning the next winter. The primary residents are the House Wrens, although we have had Tree Swallows and Eastern Bluebirds using a couple of them during the early part of the season (once they’ve fledged the wrens move in and raise a second brood there). There’s perhaps as many as three pairs of wrens on the property, although it can be a little hard to keep track of them.

Both compartments of the covered wagon had been stuffed with twigs. Wrens make very characteristic nests in boxes, you can always tell it’s a wren when you take it out. Somehow they manage to tote these twigs, many longer than their own body, back to the nestbox, pull them through the small opening, and stuff them into every corner. They fill every nook and cranny in the box, and the result is a firm rectangular nest that holds its shape even when you take it out of the box.

This wren has lined its nest with horse hair, which is abundant at the property, what with there being five of them plus a donkey within easy flying distance. You can tell which horses donated their hair to the nest by the colour of the strands. There’s also downy breast feathers from several birds, which suggests that this was a late-summer nest, after some other species had already finished raising their brood and had started moulting in fresh feathers. The bright orange one is obviously from a Baltimore Oriole; the others I’m less sure about, but could possibly be from a robin.

In the compartment on the other side of the wagon was this nest, which fell apart as I removed it. It had no lining and appeared to never have been finished. House Wren males will build multiple nest structures that they then show off to their prospective females. The female decides which one she likes best, and then works to finish lining it to start the family in. You can tell a lot about the surrounding trees by what the wren has stuffed in its box; in this case, the box isn’t far from a grove of cedars that would have provided a fair bit of easy, short building material.

This is the Tree Swallows’ box. They usually arrive early in the spring (perhaps in the next couple weeks) and start checking out the boxes in the yard. They invariably choose this one in the end. They raise one brood and then move off. They leave at about the same time that the wren is looking to start up a second brood (or a third), and he’ll often move in to build his own in there.

Here’s the house with the door open. I can’t recall now whether we cleaned this house out between tenants or not, but the wren’s twigs go right down to the bottom of the box, so it’s possible we did, or he stuffed more in there around the swallow’s nest. Either way it’s very much a wren nest now. They like for their nests to be a certain height below the entry hole, and will fill the bottom up with twigs to bring the lined nest up to that height as necessary.

The hole in the covered wagon is much closer to the bottom than in this nestbox, and so the twigs were used more to fill the back of the space than to fill the bottom, you could actually see the snow through the bottom of the cup. In this case they needed to bring the height up a fair bit, and the bottom two or three inches are solid twigs. I’m not sure what laundry Mom was hanging out on the line at the time, but it may have been a sleeping bag or comforter – the lining at the top of the nest is partially composed with synthetic fluffy filling.

When I opened the nest up to check out what the wren had used in building it, I was surprised to discover something in it. At first I thought it was a clump of fur, maybe leftover from an owl’s rabbit kill or something like that, that the wren had picked up. But it turned out to be a little baby wren, old enough to have fledged, but still in the nest. Why?

The answer was in its position. One leg was stretched out way in front of its body, and in removing the little bird from the nest I found a strand of the synthetic filling wrapped around its foot. I actually had to snap the strand to get the bird out of the nest. Evidently the nestling had become caught, and couldn’t leave the nest when its siblings did. It would have starved to death as a result. It’s rather sad.

The nestling was soft in my hand. They are the most beautiful mousey brown, even the colour suggests soft. Their wing feathers are a little rustier, particularly when young, and barred in neat lines characteristic of wrens. I left it in the nest contents where I found it. I feel sad for it, but I also have to consider that this is nature. Perhaps only one of those young birds that left the nest last summer will survive to return to the area this spring. A bird’s first year is brutal, and the death rate among first-year birds is very high. Once a bird has made it through its first year its chances of surviving to three or four years, or perhaps even longer, is greatly increased. So instead of dwelling on this one death, I look forward to the return of these cheerful little birds, the ones who’ve made it through another winter, in the coming month.

Signs of spring

Yesterday was the first day of spring. The sun was out today and the birds were singing. My mom heard the first Red-winged Blackbird calling from the swamp. I heard a flock of Sandhill Cranes flying by, out of sight. I’m also fairly certain I heard a Brown Creeper, though I wasn’t able to find him, either.

I walked about my parents’ property looking for other signs that it was indeed upon us. For instance, the ice on the little pond, above, was beginning to melt. I checked it for frogs, eggs, or little aquatic invertebrates, but saw no signs of life yet.

The icicles on the eaves of the house are also melting.

The buds are coming out on the maple trees in the front yard.

I spotted some green grass! Admittedly, this was in a footprint along one of the regularly-traveled paths through the snow, but still. Grass.

But the most conclusive sign that spring is finally here:

The driveway has turned to mud.

A beetle from summer

When I returned to my parents’ this week my mom had brought out a beetle she had found while shopping downtown in the local town back in the summer, following a conversation we’d had earlier this week on a subject I can’t recall now. The beetle was dead when she found it, so she picked it up and brought it home with her. It was a warm reddish-tan, with large black spots down each side of the carapace, and one in the middle of the back. It’s obviously a member of the scarab beetles family, and further research revealed it to be a Grapevine Beetle, Pelidnota punctata.

Ordinarily a dead beetle on the sidewalk would probably have been passed by unnoticed, but the size of this particular beetle was what caught her eye. Below is an image of the beetle posed with a (live) ladybug for comparison. The scarab family contains 1300 species, some of them the largest beetles in North America. Grapevine Beetles can grow up to an inch long, which is not quite up to the six inches of the southern Hercules Beetle, but is still a pretty impressive beetle for this part of the country.

I’ve never seen this beetle alive myself; in fact, this is the first time I’ve seen it ever, which seems somewhat unusual for what looks like it should be a rather conspicuous bug. It seems fairly common, occuring through most of the east from Ontario south to northern Florida and west to Nebraska. The adults can be found from May to August through much of its range, and will regularly come to lights in the summer.

It inhabits deciduous forests. Adults feed on the foliage and fruit of grapevines (hence the species’ common name), but appear to do little serious damage. It lays its eggs in the summer on decaying logs, which the larva feed on during their development. Larva overwinter in the logs, pupating and emerging as adults in the spring. I found one site that offered care information for the species, but aside from a couple comments on the web, couldn’t see any evidence that it was frequently kept in captivity.

One of the features of scarabs is their club-like antennae. You can sort of see here that the club is actually many-parted. These plates are called lamellae, and the beetle can fan them out when sensing odours. When it’s not testing the air, it folds them up out of the way. This individual’s a little dusty from sitting on a shelf since the summer, but in this and the previous photo you can also see the mouthparts it uses to cut bits of vegetation. In the previous photo you can get a better view of the upper cutting mandibles, and the lower manipulating ones.

Beetles, like many insects, have hairy legs and bodies, under their smooth carapaces. These hairs are called setae, and are used for sensing the environment. Generally they sense small changes in air pressure.

Take a look at the claws at the end of this guy’s feet. The claws are primarily used to help the beetle secure itself to whatever it’s walking on. However, in scarabs the front claws are modified for digging. You can see how much more curved they are on this individual. Grapevine Beetles aren’t really diggers the way some scarabs are (such as dung beetles), but they retain the characteristics of the group.

In looking up information on beetle feet, I discovered this site that is doing research on the applications of beetle-foot design to modern technology. One of the main things they’ve developed from it is an adhesive that’s twice as sticky as glue-based tapes, and is reusable simply by washing with soap and water. I wasn’t quite clear on the specifics of the technology from their description, but it uses the principle of a beetle’s hairy feet (I gather this is a characteristic of a different family of beetles), which act like a thousand little suction cups on long threads. The suction cups adhere to the surface, while the long threads allow dust motes and other debris to slip between the affixing surfaces, so it can attach to dusty and dirty surfaces as well. The lab’s site has videos of their Mini-Whegs robots scaling vertical glass walls using the adhesive. I’m on dial-up while here at my parents’, so wasn’t able to watch them, but even just the idea is pretty cool.

Tunnels from top to bottom

When I sat down to enjoy the sunshine and do a bit of sketching in the Don Valley trails on Sunday, I chose a young sapling to sit in front of. Not for any particular characteristic of the tree, but just that I like to have something at my back. I didn’t pay much attention to the tree initially, and I hung my camera bag on a broken-off branch before sitting down. When I got up and reached for my bag, I happened to notice these lines on the bark.

They’re obviously made by some sort of insect. Curious to what it may have been, I started poking around the ‘net. The answer to this question was not nearly as easy to find as I had expected it to be. Between yesterday and then again today I’ve spent several hours typing in search terms into Google and checking out promising links. This is easily the longest I’ve spent on researching a post to this point, and I didn’t even come up with anything conclusive for all that effort.

Research for my posts usually starts with a single, rather vague, descriptive term. For instance, when I was researching the Black Knot information, my first term was “black crusty growth on twig”. You usually get a few misses at first before hitting on to what’s obviously the correct identification. In this case I started off with “bark miner”. I’m familiar with leaf miners, which create tunnels between the two surfaces of a leaf, and this looked very similar. It seemed like a pretty obvious connection, but the search produced no viable hits. I changed my approach. “mines under bark lines on surface insect branch”.

This turned up a lot of not very useful stuff, but did contain one page that had something. It was a fact sheet on the Allegheny Serviceberry. What does that have to do with insect mines? It had a section on pests. The first paragraph read, “Cambium miners cause concern when noticed but are not very damaging to the tree. The mines can extend from a twig all the way down to the roots. The mines form light-colored lines in the bark.” Aha! A lead!

So the next search term was “cambium miners”. The cambium is the layer of reproducing cells in a tree located between the outer bark and the inner hardwood which is the source of the tree’s outward growth. It’s just a narrow layer, and in a young thin-barked tree like ash, maple, birch, and other deciduous species, it’s pretty close to the surface. This seemed promising.

Most hits I found just simply called them cambium miners, without identifying the species or even the order of insects they belonged to. I didn’t find this especially useful. However, after poking through a number of hits I came across a page from an online resource called Tree Dictionary. The page seemed to be focused on pests of trees as well, and included a lot of information on various fungi. Also paragraphs on sapsuckers, squirrels, frost, beetles, and, the object of my search, cambium miners.

The page indicates that cambium miners are flies belonging to the genus Phytobia. The flies lay their eggs on branches near the top of the tree, and the young larvae mine their way through the cambium down toward the roots, where they stay till they pupate. There isn’t actually a lot of information on the life history of this genus on the web, at least that I turned up in my initial searches. I was able to determine that there are a number of different species that have different host preferences, and some are cambium miners while others are leaf miners.

Knowing the species of my tree would help. I’m not certain, as it’s a small sapling in the middle of winter with no leaves. I can rule out birch fairly safely, I would think, and cherry, because there aren’t any horizontal lines. Beech and maple would be grey. Hawthorn would have spines. But that still leaves me with an assortment of options, including common species like ash, and less common ones such as alder, hickory, etc. I’m leaning toward ash, given the location and its commonness.

On the website ForestPests.org I found an informative factsheet on the Ash Cambium Miner. The page indicates that the larvae of this fly mine in straight or serpentine tunnels near the top of the tree, but the further down they get (and presumably, the older they get), the more their tunnels take on a zig-zagging appearance until they’re distinctly so by the time they reach the roots, where they’ll spend about 10 months. They overwinter there, then exit the roots in late spring and pupate in the soil.

I continued to poke around, pressing on and changing the search terms to see if I could turn anything else up. I had a few other potential culprits, including flat-headed borers (metallic wood boring beetles, the group that includes Emerald Ash Borer), and small moths of the genus Cydia, but none of the online resources seemed to match as well. I’m still not positive on calling them Phytobia sp, either, given that I couldn’t find any resource showing their mines to be able to compare to the ones I photographed, but the information all seems to match pretty well.

Today I spent the day laying laminate floor in the family room at my parents’ house. I’m pretty sure that laminate wood flooring is a little like vinyl tile in that they make the wooden planks out of pressed particleboard (or something resembling it) and then print a design on top, rather than laying an actual wood veneer over it. However, I assume they use an actual image of woodgrain to create the print image, so the laminate planks represent actual woodgrain patterns.

What does this have to do with cambium miners? Well, on both of the sites mentioned above, they indicate that the mines left by the larvae get grown over as the tree continues to grow and result in small discolourations in the wood. These show up as small dark marks on stumps when the tree is cut or, as in the case here, in wooden planking, where they’re called “pith flecks”, among other names. They apparently don’t show up in ash wood very well, but are fairly noticeable in most other types of wood. I’m not sure what type of wood this laminate is supposed to be an imitation of, but it’s got a distinctly reddish tinge.

Here’s a close-up of the pith flecks in the woodgrain of the laminate print. You can see nearly all of them are associated with the tree-ring growth mark, where the larva would have been tunneling close to the surface of the bark (the dark growth line). A couple of the marks are further in; apparently there are some species that will occasionally feed in the xylem (the layer under the cambium) for short periods, and that could be what these are.

Despite that these marks are due to insect damage, they’re not generally considered defects of the wood by most lumber manufacturers, but they are recognized as such by the Fine Hardwood Veneer Association (who knew there was such a thing?). I suppose that, over the course of a tree’s life, there’s a good chance it will be infested at least once so it would be hard to completely eliminate the marks from wood products.

Insects. They’re everywhere.

Solitude in the heart of the city

This morning I got up early, leaving Blackburnian still asleep in bed, and slipped out the door with my camera and sketchbook to go to one of my favourite spots in the city. Unlike the Rouge, this area is just a short drive, perhaps ten minutes along in-town roads, located in a section of the Don River valley. I discovered it a couple of years ago, when I was hired by the city to do a report for them on one of their properties. This was the area I chose to use as a control site during my study. I chose it initially because it was un-groomed, natural and wild, and over the course of the next several months I really fell in love with the location.

It’s accessed from a small park and playground, through a short, narrow mini-ravine that runs between two rows of houses. The trails are used almost exclusively by the local residents for jogging and dog-walking. I encountered very few people on the trails during my surveys. This morning, in the hour and a half I’m there, I meet no one. This is one of the things I love about the place; it’s quiet, peaceful, relatively undisturbed, and you can almost forget you’re in the heart of the city.

Halfway down the entry trail I notice these snowballs. The sides of the mini-ravine here are steep, and evidently something, perhaps a fallen twig or bit of bark, began sliding down the side of the slope, gathering snow about it as it went. It’s not the typical snowball you see when snow rolls down a hill, and I have to assume that the object slid rather than rolled, and spun as it did so to create these neat doughnut shapes.

The entry trail meets up with the main network, and I turn to follow it to the north. It runs along the base of another set of homes. I think how magnificent the view from their back porches must be, and then I think they must command a real premium on house price for such a location. Indeed, most ravine-backing homes are way out of my price range in the city, usually starting at $500-600k for the small run-down places, and going up to well over a million for the really nice ones. Toronto is a wealthy city. It has to be, in order for so many people to live here, with property prices being what they are. In the neighbourhood where we rent you’re lucky to find anything in good shape for less than $300k. I couldn’t afford to buy here on my own. Even Blackburnian and I together would be hard-pressed to find something we could afford jointly. Who are these people, making all this money?

I turn west down a small side trail, and am afforded my only real view of the city as a backdrop to the park, with a few tall apartment buildings towering over the treetops, at the far side of the Don. A short distance down the trail and the city melts back into the trees, hidden from view, and forgotten, for the moment.

The side trail comes out at a bluff, overlooking a bend in the Don where a gravel bed has been exposed. During my surveys I always scanned the gravel for Killdeer or Spotted Sandpipers, but never saw either, despite it looking like a good spot for them. I did once see a Black-crowned Night Heron fishing from one of the low-hanging trees, but the bend, for all its nice scenery, was always disappointingly empty.

I pause, and look out over the river. The sun is peeking above the trees and casting a warm glow on the bare canopy of the forest across the way. It hasn’t yet reached the river, or even where I’m standing. I briefly consider stopping here, but decide I’d like to sit someplace in the sun, and move on.

The trail goes down a small incline (decline?) and where it levels out it passes through a small grove of spruce. Their lower branches have been pruned from them years ago to make room for trail users to pass through, which gives them an unusually domesticated look, for someplace far from the nearest backyard. In this natural tunnel I recall frequently encountering chickadees, kinglets, and Yellow-rumped Warblers during my spring surveys. There is no one here at the moment.

In other areas, though, the trees are full of song. The cardinals have woken with the dawn, and perch in the upper branches of the poplars, illuminated by the warm orange rays of the rising sun. There are at least a dozen of them, I estimate, throughout the area. They all belt out their declaration of possession of their claimed bits of woodland. “Cheer! Cheer! Whit-whit-whit-whit! … Birdy, birdy, birdy-birdy-birdy-birdy!”

The other birds join in. I hear a pair of White-breasted Nuthatches arguing back and forth at each other over the ownership of a particular patch of cedars, and briefly glimpse a short chase as they dash through a small clearing. A pair of male Downy Woodpeckers has at it over the attentions of a female, who seems rather blasé about the whole episode. House Finches fly over the site in groups of two or three, and I hear the odd male singing. Chickadees move through a patch of hawthorn, calling to one another, and a trio of crows perches atop the maples and caw loudly. The birds seem to be as happy about the sunny morning and approach of spring as I am.

I come out from the spruce grove along side the river, at a lower area along its banks. The river takes another turn here and is lost from sight, winding its way through the city toward Lake Ontario. It is beautiful here, natural and undisturbed, but along its length it will run through less pristine areas, ultimately coming out through an industrial zone at its mouth before exiting into the lake. A freeway runs north and south through a large part of the valley system, but is far enough away here that I don’t notice it. A rail bed also runs along the valley, and a train thunders by while I’m there. It’s just beyond the ridge, and I can’t see it, but I can certainly hear it. I’ve seen salmon in these parts of the river before, and it seems at odds with the surrounding city, particularly considering the state of the mouth of the river. Nature forges onward.

I decide to take a trail branch that I’ve never been down. On this section of the trail I had always been in the middle of my survey and was unable to follow the side branches. They were often muddy, too, compared to the main trail. However, a few people have been down here recently, and the snow is packed enough to walk along comfortably. I come through another small grove of spruce and the trail widens into a small open area. The sun is streaming in here, and the spruce protect me from the wind. The clearing feels cozy, and I decide this is the spot. I find a log to settle on, and pull out my sketchbook.

I am not ordinarily a field-sketcher. Usually I’m too busy watching birds or taking photos to settle down somewhere and sketch. I admire those who do, though. Debby at Drawing The Motmot is a fabulous field-sketcher. I absolutely love her rainforest studies, which are done in pen while sitting in the field, over as many as three days.

While I have the skill to execute those sorts of drawings, I am sure, I also know I don’t have the practice, or the patience, right now. There’s too much to do, to look at, and I haven’t disciplined myself to sit still long enough to study the landscape and develop the eye necessary to render such detail so accurately. I content myself to sitting for perhaps 20 minutes, soaking up the warm sun, and casually sketching the trail in front of me. Perhaps I’ll make an effort this year to pause more often and sketch a little more.