The Marvelous in Nature

Easter birds

At my parents’ for Easter dinner yesterday, I popped outside for some around-the-house birding while waiting for the turkey to come out of the oven. I decided not to venture further because there’s still quite a bit of snow on the ground, and with the (slightly) warming temperatures it’s quite soft now. Also, the driveway practically requires galoshes to navigate cleanly, and I haven’t unpacked mine from the winter yet.

There was still a fair bit of activity even just around the house, which is where birds congregate due to the presence of the feeders. I had to wait a little while, but I did finally get to see the Red-winged Blackbirds that my mom had reported arrived the other day. They usually come to the seed spread out on the driveway in front of the house, but yesterday they were sticking to the cast-off litter under the feeders in the backyard, possibly because of the seven cars parked in the driveway turnaround surrounding the seed. One also visited the suet a couple of times, which was where I got the best photos of him.

This is just a youngster, a second-year bird, meaning he was hatched last year (as birds’ ages are labeled by calendar year – he won’t truly be a year old till the summer). You can tell because the black feathers on his back and wings are fringed with orangey-brown, a characteristic of young males.

American Goldfinch and Red-winged Blackbird

Behind the blackbird, a couple of American Goldfinches were coming to the nyger feeder. They’ve been mysteriously absent for the last couple of months, only just starting to return recently. I’m not sure where they all went. Normally they spend the winter mobbing the feeders in fairly substantial numbers. The most I’ve seen at a time since mid-winter has been three.

The males, like this guy, are starting to get their brilliant summer yellow plumage. You can see it all beginning to come in around his face. In the middle of winter you can still tell the males from the females despite their relatively drab plumage because some males will retain slightly brighter yellow faces. Also, their wings and tails are a sharp, crisp black, rather than the duller brownish-black that females sport.

The starlings have settled in. There’s at least a couple of pairs present now, with the two males often counter-singing to each other from their respective territorial perches. This particular male seems to have chosen the north peak of the house as his nest site of choice. Here he pauses in his singing to check out the activity (me) below. Two starlings, a Blue Jay and a White-breasted Nuthatch are the birds to have discovered the suet dough, so far. The nuthatch takes respectable small pieces, but the other two species really toss it back when they visit the feeder.

While standing out there watching the feeder birds, I glanced up at a crow crossing the the sky, and happened to spot, up high behind it, this Red-shouldered Hawk moving with purpose to the north. It was right at the reach of my (relatively) short 300mm lens, this is a close crop on the original image. There are a pair of Red-shoulders that live in the neighbourhood every year. I’m not sure where they nest, other than that it’s somewhere to the west of my parents’ place. I regularly hear them calling from that direction in the summer.

I recall some years ago there being some concern over decreasing populations in the province, but I think these declines are more limited to the southwestern portion, west and southwest of Toronto. That said, the recent Ontario Breeding Bird Atlas recorded them in quite a number of areas where they hadn’t been 20 years ago. There is some likelihood that this is due in part to new surveys that were implemented for the species by Bird Studies Canada in 1991, contributing a lot more targeted effort than took place in the first atlas. Still, even taking this into consideration, the results of the atlas are encouraging, and probably suggest increasing forest cover in the south of the province as abandoned fields regenerate. They remain an uncommon species in most of my “home range”, and I’m always pleased to see one.

Also on the raptor front, although I wasn’t able to get a photo, I spotted a Turkey Vulture circling over the escarpment, the first of the season. They migrate south for the winter, so are always a welcome sight in the spring. Come summer you can usually see at least one or two over the escarpment where the topography of the cliffs creates great thermals for soaring. During the peak of migration you can have up to a couple dozen.

This Common Redpoll has been hanging around the feeders for a little while, she was there earlier in the week as well. She doesn’t seem to be doing too well, although I’m not sure what she might be ill with. She was feeding periodically, and moving around on the ground, but at other times would just sit on the feeder perch or at the top of the birdhouse in the centre of the garden, looking around but otherwise not doing much.

She’s identifiable primarily because she’s always fluffed up into a near-spherical shape. Fluffing like that is a bird’s way of putting on extra layers – when we would go grab an extra sweater, the birds will fluff up their feathers. The amount of fluffing is similar to the number of layers of clothing, as the air pocket trapped under the feathers, which traps warm air close to the body, will increase as the feathers are further raised. None of the other birds were fluffed this much, it wasn’t that cold out. Birds that are sick will usually fluff their feathers as well, I suspect in a similar reaction to our burying under the covers when we have a fever and are suffering chills.

She was too active for me to consider trying to catch her, and she is continuing to eat, so that’s in her favour. However, she was still sitting at the feeder at dusk, one lone redpoll. I hope she gets well.

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.

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