the Marvelous in nature

The purpose of the visit to the pond last week was primarily to check out the creatures in the water, not the forest paths, as much as I enjoyed that. We didn’t see any of the salamanders on this trip; as plentiful as the newts had been a couple weeks ago, they were now conspicuous in their absence. In fact, there didn’t appear to be any macro-life in the pond, at least that was visible from the water’s edge. However, there was still lots of micro-life.

We scooped up a number of samples of pond water and bottom-muck, and let it settle out in a basin. Then we poked through it to see what we could find. Copepods were abundant, as well as a number of other little, microscopic creatures that were best observed with magnification. There were also quite a number of large critters, which could be observed easily (and photographed).

The above is a predaceous diving beetle, probably of the genus Neoporus. The group is also sometimes known as water tigers in their larval stages, for their predatory habit, but it also well suits this black-and-orange adult individual. Adults propel themselves with their broadly flattened hind legs, which they use as oars (but don’t confuse them with oarmen or boatmen!). I noticed while trying to get a photograph of this guy that whenever he stopped moving he’d go bottoms-up, with his head tipping forward to point toward the bottom of the tub. It was not especially helpful in getting a good photo, but this is how they collect air to breathe - in tipping forward like this they trap an air bubble underneath their wing covers which they carry with them while swimming. They’re not strictly aquatic; they can fly and will travel in order to exploit temporary water bodies.

This is the larvae of a skimmer dragonfly. Dragonfly larvae, or nymphs, are entirely aquatic during this first phase of their life. Adult dragonflies lay their eggs in the water, usually attached to vegetation, where they develop and hatch. A dragonfly spends most of its life in a larval form. Some species can remain in the water as a nymph for up to five years, depending on the species and the local environmental conditions. During this period they’ll go through more than 20 instars, or larval stages, where they moult their skin to grow. The different types of dragonflies have differently shaped larvae; the skimmers are short and squat, like this guy. Nymphs are predaceous, feeding on other invertebrates, or even sometimes small fish or tadpoles. When they’re ready to metamorphose into adults, they’ll climb up a stem out of the water, where they’ll split their skin and crawl out as an adult form. The newly emerged adult will take a few hours to strengthen up and gain its adult colours.

This is a blackfly larvae. I didn’t know what it was when I first spotted it in the water. It moves along much like an inchworm, securing one end, then moving the other, rather than crawling like a caterpillar, or wiggling like mosquito larvae. It uses suckers on its bulbous end in order to firmly attach to its substrate. If they happen to become dislodged, they remain secured to the substrate by a thin silken strand, much the way a spider that gets knocked or blown off will catch itself on a string of silk before it reaches the floor. This prevents it from getting swept away in the currents, but can also be used as a controlled way to move from one point to another within their habitat. They tend to prefer the faster-flowing segments of streams or creeks, but can be found in ponds as well. A small, leg-like appendage under the head can create a small current where none otherwise exists. They’re mostly filter-feeders, using “gills” near their head to sieve food from the water as it flows past, which is where moving water would be advantageous.

I expect that most people will recognize this bug. It’s a water strider (also known by a dozen other names of a similar theme), usually found skittering across the surface of still water such as ponds or lake edges. However, they’ll also inhabit faster moving streams, and in fact this particular one came from the creek where we caught the crayfish, although there were also some on the pond surface as well. Predatory insects, feeding on other insects and invertebrates found on or near the water surface, they can scoot across the water as fast as 1.5 m/s (nearly 5 ft/s) - per second! They need this speed to be able to catch their prey before it takes off. They’re able to stand on the water through a combination of structural and chemical water-resisting features. They have a wax covering on their legs, but the more important factor is a series of tiny hairs with grooves that line each foot and spread out the pressure of their foot on the water surface, while simultaneously trapping air between the hairs, acting a little like snowshoes combined with waterwings. At certain times of year adult striders of some species can develop with wings, which allows them to disperse from one area to the other; in other species they always have wings.

This was my favourite of all the little critters we swept up in our container. We got several of these, little tiny guys just a couple millimeters long. They sit on the water surface, much like the water striders. However, to move around, they jump like fleas. In fact, I think the name “water flea” would be much more appropriately labeled to these guys than to the microscopic Daphnia. They jump by using a mechanism similar to the click beetle in yesterday’s post. They have a long spike on their abdomen, resembling a “tail”, which is generally kept locked into place. When they want to jump, they release the clasp and the spike rapidly springs away from the body, pushing against the substrate (in this case, the water), and propelling the insect forward. It’s this jumping mechanism that gives the group its name. They can be found in nearly every habitat, even on the snow surface in winter - these ones are appropriately called “snow fleas”. Interestingly, unlike with the water striders, this speed isn’t for capturing prey, but rather for general locomotion and avoiding predators, as they’re primarily savengers, feeding on decaying plant and animal debris.

On Tuesday I bought myself an early birthday present. I’ve been wanting a good macro lens for a while. In the winter I got a Canon close-up lens, basically the equivalent of a magnifying glass that you screw on to your existing lens like a filter. It worked fairly well, but unfortunately the lens that I had wasn’t top quality, it was the entry-level telephoto lens that came with the camera kit bundle. Sure does me fine for a beginner DSLR-er, and the price was definitely right (next step up is megabucks, relatively speaking), but because it’s low-end the optics are soft and the photos are never crisp. Generally this can be corrected with digital sharpening in Photoshop, but with the addition of the close-up lens, which softens the image a tad more, it was really hard to get good sharp shots without a tripod and ample light.

So I’d been eyeballing a dedicated macro lens. I find macro photography fascinating, because, unlike most wildlife photography, it’s a world that we don’t ordinarily see with our unaided eye. We also tend to overlook a lot of the small stuff, and I wanted to be able to capture these things to share with others. I wanted a lens that wasn’t afraid to get in there, and that would produce good sharp photos while doing so. The answer was the Canon EF 100mm f/2.8 USM Macro (quite a mouthful of a name!). I did a lot of research, and the general consensus was that the Canon 100 was the best bang for the buck at that price level. I couldn’t find a bad review. So I bought it.

I took it out to test-drive it that afternoon, swinging by the Leslie Street Spit, which wasn’t too far out of my way. It was unfortunately quite windy, and a little cool, and I had other errands to run after, so I didn’t stay out too long. I focused on the dandelions that were growing along the edge of the parking lot and nearby path, pretty much the only wildflowers growing yet in these disturbed areas. There didn’t seem to be anything visiting them, no bees, no butterflies, no insects of any sort. Until I looked closely. There, crawling around at the base of the petals, deep within the flower head, was a teeny-tiny ant. It had a slight purple sheen to it, and its antennae were tipped with pollen. I don’t really know what it is (aside from colour and general size, ants are so similar to each other…), but it does resemble the Odorous House Ant in the Kaufman guide to insects. I gather it’s not limited to houses, despite its name, and the “Odorous” comes from its habit of emitting butyric acid, which smells of rotting coconut (presumably someone who lives where coconuts grow, and subsequently rot, would know better what this smells like).

The above fly, although also on a dandelion, was from a couple days later, when I was back at my parents’ place. It was also the only insect I found on the flowers. Like the ant, flies are difficult to identify, but this might be Cheilosia sp., a type of flower fly from the family Syrphidae.

Later that day my mom and I returned to the same pond site where we found the salamanders for another check-up visit on the status of things for a program she’s doing next week. We decided to walk down the trail through the woods a little ways, looking at the wildflowers and seeing what was blooming. We were mostly focused on the flowers, so nearly overlooked this beetle, even though it was sitting out in the open on a leaf.

It’s a click beetle, though species is uncertain. Click beetles are named after a characteristic noise they make. They have a spine on the underside of their thorax that snaps into a groove a short ways further back. It’s the snapping of this spine that produces the distinct clicking noise. The noise is primarily used to distract predators, but the spine can also be useful for flipping the beetle back right-side-up if it gets turned over. The action can be quite violent sometimes, jumping the beetle some distance into the air.

Further down the trail I stopped to photograph some trilliums and found this brightly-coloured beetle perched on the edge of a flower. I discovered, when I went to look it up in the field guide, that there are quite a number of long, narrow black beetles with red collars. This particular one had the unique characteristic of two bumps on the red thorax that made it easier to distinguish from the others, but I still had to submit the image to BugGuide.net to get an ID for it. It’s Asclera ruficollis, a beetle of the northeastern woodlands. Adults are found feeding on the pollen of wildflowers during the spring period, from March to May.

The last bug of this post was a little moth that flitted across the trail as we were walking. I tracked it a short distance off the path, where it came to rest on a dead log. If I hadn’t watched it land, though, I may have been hard-pressed to locate it again. It’s just a small moth, maybe a centimeter (half an inch), and cryptically coloured so it blends in with the wood (it looks fairly obvious here because I’ve isolated it with the camera, but believe me, it wasn’t). I think it’s a species of Pseudexentera, though I don’t really know which one. I could even be wrong on the genus. All those micros can be so tricky to ID! There just aren’t a lot of field marks on their tiny wings to reference.

Going out with my new lens in hand, I was looking for little things to photograph, but I was somewhat focused on the flowers. The lesson here: look carefully and pay attention, there’s lots out there that you can just walk right by without even noticing!

Just a short ways down the road from my parents’ house is this little creek. I don’t know its name, or even if it has a name. It meanders through the woods to either side of the road, backing or crossing through various properties. I’ve always wanted to wander down its length, but never plucked up the courage to brave the potential encounter with a displeased property owner.

But I admire it from the road’s edge whenever I drive through. My sisters and I would come down here sometimes when we were young. We liked to drop sticks into the flowing water and see whose came out from the other side of the bridge first. I recall occasionally pushing through the vegetation, either to look at the little chub that swam in it, or to pursue the damselflies that danced along the water’s edge. In the summer it’s lined with grasses that will slice your skin like a papercut, so I either had to be especially keen or otherwise well-covered to want to approach the water.

Every spring I watch it for the first signs of the Marsh Marigolds. They’re such a cheery spring flower, and the first ones out in the creek corridor. There were some blooming last week when I visited, and I thought that was the show, but this week they abound. I’ve noticed they’ve been featured on a couple of other blogs that I read, in particular A Passion for Nature; they’re just that eyecatching.

They’re part of the buttercup family, Ranunculaceae. There’s about 2500 species in this group of plants, found across all continents, but most prominently in the palearctic. Most species have flowers that are radially symmetrical (meaning it will look the same from any direction), though a few are bilaterally symmetrical (have a definite up/down/left/right). In their centres they have a small forest of pistils (the female organ) surrounded by stamens (the male organ). Insects come to collect pollen and also to sip at the nectar that is produced at the base of the pistils. In doing so, the pollen sticks to their bodies and they spread it from one flower to the next, easily done when the parts are all so close together.

All members of the family contain a compound called protoanemonin, which is toxic to people and animals. Many species also contain additional compounds, especially concentrated in the sap and in new shoots; buttercups and clematis contain glycosides, which are potent skin irritants, while Marsh Marigold, delphinium, monkshood and larkspur, among others, contain highly toxic alkaloids. One site recommends only handling these plants while using gloves. Some particularly sensitive-skinned people may find that necessary, but I’ve never had any reactions to handling any of these plants (for instance, buttercups - kids pick them and hold them under their chin to see if their chin glows yellow… which means something. Probably to do with love, since that’s a popular theme among kids games. But I’ve never heard of kids getting rashes from doing so).

Apparently these properties make it useful for a number of medicinal purposes, however, including removing warts (I guess the sap effectively burns the tissue). A tea made from the leaves can be a diuretic and laxative (that would be the poison aspect of it kicking in there), and other aspects of the plant can be used to treat fits, anemia, and even the common cold.

They tend to grow in discrete clumps, rather than as broad swaths of the flower. This patch was in the ditch right next to the road and I didn’t even need to get my feet wet to photograph it. They aren’t limited to streamsides, though that’s often the place they’re most easily seen since road bridges allow unobstructed views of the water’s edge. They can also be found in the soggy ground around wetland and marsh edges, and in bogs, fens, and swamps. Partial shade is their favourite, they’re unlikely to do well in heavily canopied forest swamps or wide-open marshes.

In some areas they’re a common garden flower, planted in water gardens or soggy areas. They grow well, and their showy, early flowers make them very appealing. They can be easily bought from many nurseries, and there are a number of different cultivars now available.

According to Wikipedia, the common name, Marigold, apparently refers to the flower’s use in medieval churches at Easter in celebration of the Virgin Mary. However, I know there’s more than one plant called marigold, so it may be that, like the North American robin, one was the species truly used and the others were just flowers that reminded the namer of the first species.

The species is also sometimes called Kingcups, though I’ve never heard them called that myself. They’ve got many local or little-used, but colourful names as well: Mayflower, May Blobs, Mollyblobs, Water Blobs, Water Bubbles, and the Publican, among others. I have no idea where they get “blobs” from, or even Water Bubbles, since they look like neither to me. I would suggest that these names were inserted into Wikipedia by someone as a lark, but I have actually seen them mentioned elsewhere, as well. Wikipedia suggests that these other names for the species reflect the plant’s persevering nature, especially through the often inclement weather of spring. I don’t get that either, really…

Towards the end of April I happened across a few observations that I thought would be interesting to post as a wrap-up to earlier topics.

This first one is going back to the jumping spider that I watched pounce at (and miss) a smaller brown spider. The following week I came across the above perched on one of the legs of my tripod. It was huge! Well, relative to my first little guy. It was easily a centimeter and a half long. Black and hairy, with striking orange markings, hard to miss. But the most eye-catching thing about this little spider was its fangs, a radiant metallic green.

The spider belongs to the genus Phidippus, but I’m unsure of the species. The metallic fangs are characteristic of this group, and are used in impressing females in courtship dances. The genus is primarily restricted to North America, and includes some of the larger jumping spider species. Julie Zickefoose apparently has a little black one that keeps her company while working. His name is Boris.

A bit earlier, I had found this guy hanging out on the wall of the station building. Unlike the individual from my original post, this one had had better luck hunting. He’s munching on a midge, which are extremely common down there.

I came across this butterfly at the end of the morning one day. It was flitting from one tree to another and paused at this birch briefly. I identified it as a Painted Lady, and didn’t really give it much further thought. Then, while preparing the photos for this post I decided I should just double-check that it was a Painted and not an American, because I couldn’t remember which one had the spot on the wing. Well, turned out it was neither. I hunted through the entire Kaufman guide to butterflies twice before realizing that it was an extremely worn, rather orange Compton Tortoiseshell. The first one I’ve ever seen. But now I wonder if I’d been seeing them but writing them off as the more common Ladies.

It was pausing at the birch trees, and when I looked closer I realized it was drinking sap from fresh sapsucker wells. This species overwinters as an adult and comes out in early spring, much the way Mourning Cloaks do. Because it’s still quite early for nutrition in the form of flower nectar, they take some of their food from other sweet sources, such as sap wells (mentioned in the original post about the Yellow-bellied Sapsucker).

And finally, returning to the Pussy Willows. The same day I had the tortoiseshell, I also observed three or four Mourning Cloaks visiting the buds of this Pussy Willow. For the same reason that the tortoiseshell was sipping at the sap wells, these Mourning Cloaks were drinking the nectar available from the female flowers of the willow. I love the velvety red-black of the wings in sunlight. Most butterflies I see that overwinter as adults look a little ratty in the spring. The tortoiseshell had a chunk missing from its wing like a bird had snapped at it. This Mourning Cloak seems to be missing a piece from its hindwing.

Fancy Daffodil

I’ve always liked that phrase. A selection of blooms from my mom’s garden. I’m cheating a bit, these were all taken in April. But most of them were the last couple days of April - that’s close enough, isn’t it?

Daffodil

Hellebore

White Trillium

Frilly Daffodil

Snowdrop

Red Trillium

Crocus

Boy, has this week flown by! Here we are at the weekend already and I feel like the week’s only just begun. Part of this has been the progression of a new project. TheMothMan and I are starting work on a new field guide to the common moths of northeastern North America, which we’re pretty excited about. I haven’t wanted to say anything till I felt it was sure to go ahead, but we just secured an agent to represent the book so it looks like it should be more a question of where, rather than if, it gets published. Our agent also represents such notable naturalists and authors as Julie Zickefoose, David Sibley, Pete Dunne, Lang Elliott…. excuse me while I geek out for a moment. How often does something happen to bring you two degrees of separation from your idols? It’s only slightly less thrilling than if I’d met them in person.

Okay, composing myself… back to the topic at hand. Moths as well, as it turns out. Or rather, their larvae.

The above photo I took a few weeks ago, at the beginning of April. It completely encircled a small branch of a small tree, with white egg surfaces on top, but a crusty golden layer across the bottom. It wasn’t very big, perhaps a couple centimeters at most in its longest direction. I filed it away as “unknown insect egg mass” and there it stayed for a couple weeks. Then, while looking up something completely unrelated (always the way, isn’t it?) I stumbled across a photo in the ID Request section on BugGuide.net that looked just like my egg mass.

They were Eastern Tent Caterpillar eggs. They were especially conspicuous against the dark bark of the tree they were on, or I may not have noticed them at all.

This week, when I arrived at my parents’ for a couple days, I was struck by the huge number of web tents in the trees. I wondered if there really were an unusual number this year, or if it was just that I was taking more notice this year, what with the motivation of potential blog entries making me more attuned to these sorts of things. Either way, there seemed to be lots of them, two or more in a few trees even.

My mom pulled out her handy dandy Stokes Guide to Observing Insect Lives and we looked it up (my images are nicer… ). Over the winter we’d investigated Chokecherry Tentmakers. Thinking that I’d seen several webs in the chokecherry out front, I’d suggested it was these. In fact, they don’t appear till later in the summer. The only web tents found at this time of year are those of the Eastern Tent Caterpillar (Malacosoma americanum).

There are two primary species of tent caterpillar: the Eastern and the Forest. The Forest is associated mostly with oaks and maples. The Eastern is found on trees of the Rosaceae family, most notably apple (cultivated, wild, and crabapple) and cherries (cultivated, Black and Chokecherry), as well as hawthorn, pear and plum. Indeed, when I really stopped to look, all the tents at my parents’ appeared to be in the chokecherries, the crabapple, and the cultivated apple trees. And the little tree where I’d found the eggs at the station was also a young apple. When I checked back this week, sure enough, there was a little tent.

The most obvious sign of their presence, of course, is their web tents. When the caterpillars hatch out of their egg cases they migrate along the branch till they reach a major fork, where they set up shop. This is another feature that tells the tent caterpillar apart from the webworms; tent caterpillar nests are never out at the end of the branches. The young caterpillars all band together in an amazing show of cooperation, building the first little nest to get them started.

As time progresses and the caterpillars eat and grow, they build more layers on the nest to expand it. They lay down silk on the outside of the nest, and as it dries it tightens, eventually separating from the layer it was laid down upon. This creates a stratified effect within the nest. As the caterpillars grow they need more room, but they also require additional layers as the existing ones become filled with frass and moulted skins. The caterpillars leave a hole or two in the webbing, usually near the apex but potentially anywhere, by which they come and go from the nest. You can see the hole here. They tend to lay down the most silk on the side that faces the sun most directly. Usually this is the southern or southeastern side, which allows them to catch the morning rays more efficiently to warm up at the start of the day.

You can see in this picture, of a relatively new nest beside my rather dry fingertips, just how small the caterpillars are to start off. They use the nest for a number of purposes. The first and perhaps most obvious is for protection from both predators and the elements. When not feeding, the caterpillars huddle inside the tent. They also use the outside of the tent for basking or huddling to raise their body temperatures prior to heading off to feed, which you can see them doing in this photo. They pack together like this to reduce individual heat loss due to air movement. The stratified layers within the nest also help them thermoregulate, as the silk traps heat like a mini greenhouse. By moving in or out as needed they can adjust their temperature.

As the caterpillars move about, they are constantly laying down silk secreted from a spinneret at their tail-end. In going to and from the feeding areas they end up creating silken trails along the branches. They appear to follow these trails when moving, but they’re actually following a trail of pheromones that are also laid down by individuals. Initially, or once a particular source is depleted, individual caterpillars will go on “scouting” trips, looking for good food sources. So that they can find their way back to the nest they leave a scent trail to trace their steps. If they found a really good source of food, on their way back they lay down a stronger, more specific pheromone trail that tells the nestmates where the good stuff is. Well-traveled trails will be strongly defined with silk, while new or lightly-traveled trails may be barely visible.

Here you can see the empty egg cases of the little caterpillars, with a silken trail leading away towards the nest. The eggs are laid by the adult moths in the late spring or early summer, about 200-300 in a single egg mass. It doesn’t take long for the caterpillars to develop within the eggs, only about three weeks. However, they then remain dormant until the following spring. They hatch out just as the leaves are beginning to unfurl. Occasionally, the caterpillars from two or more egg masses laid close by to each other will come together to form a single colony. I think that’s what happened in the case of this bunch, since I found at least three empty egg masses within the same branching system, but only one nest.

The caterpillars will eat and grow and shed their skins and eat and grow some more for 4-6 weeks. They’ll go through six larval stages, or “instars”, each one still a caterpillar, but getting progressively larger. In their sixth instar they stop laying silk down on the nest or trails, instead conserving it for pupating. It’s during this stage that you usually find the caterpillars on sidewalks, benches, roads, and elsewhere, as they disperse from the nest to find a safe location to spin their cocoon and pupate. The cocoon is usually tucked into a corner or crevice, and is fuzzy and imbued with a yellow powder.

The caterpillars come out of their nests three times a day to feed, all corresponding with the times of lowest predator (especially bird) activity: at the crack of dawn, in early afternoon, and at dusk. The only deviation to this pattern is in their final stage, when they only emerge at dusk. They back this up with a chemical deterrent. Apple and cherry tree leaves, in particular, contain small amounts of cyanides, which the caterpillars ingest. When disturbed they produce cyanide-laden fluids to dissuade predators.

Tent caterpillars are much-maligned because they’re a defoliator. I recall as a kid being under the impression that tent caterpillar nests, when found, should be cut from the tree and burned to prevent spread of the infestation. What a dramatic reaction! An individual nest will not do significant harm, and in fact even an outbreak of the insects will not do any lasting damage to a tree. The caterpillars rarely kill their host trees, usually only if the tree was already weak or damaged prior to infestation. Any defoliation caused by the insects will generally regenerate later in the summer, once the caterpillars have headed off to pupate. Of course, depending on the size of the colony, it may be possible that that year the tree doesn’t produce any fruit. I think this may be where their bad rap stems from - they would be nuisance pests in orchards where they may stunt the fruit crop for the year. They are likely also perceived as unsightly in suburban settings (both their nests and the resulting defoliation). But really, they’re pretty harmless.

The only potential problem the caterpillars may cause is they’ve been implicated in Mare Reproductive Loss Syndrome (basically abortion by horses). The going theory is that the hairs of accidentally ingested caterpillars may puncture the intestinal walls and provide a conduit that allows bacteria to enter the uterus.

I like to cheer for the underdog (unless there are obvious good/evil sides), and so I support the tent caterpillars, much as I back Purple Loosestrife and Brown-headed Cowbirds (subjects of future posts, I’m sure). They’re a good food source for many creatures, including as many as 60 species of birds, maturing just when the birds are looking for bugs to take home to feed the kids.

A week and a bit ago, when I was down at TTPBRS to allow the coordinator a much-needed day off, we caught a Rusty Blackbird. It was a rather slow morning, we hadn’t caught many birds, so this caused a bit of excitement. Although Red-winged Blackbirds are a dime a dozen, Rustys are the opposite. We see them every season, but in very small numbers, rarely more than one or two at a time, and usually only a handful over the course of the whole season.

This year the water levels are very high on the lake, possibly the highest we’ve seen them in the five years we’ve been there so far. A couple of our net lanes are located close to the water’s edge, and as the water level has crept up, the lanes have become flooded, such that we now require rubber boots to be able to wade in to check them. This is great Rusty Blackbird habitat, as they, like their cousins the Red-wings, are partial to water, and indeed this was the net the Rusty was caught in.

As we do with all birds, we banded him and took a few measurements and then let him go (after an obligatory, but short, photo shoot). He flew up into a nearby birch where he perched for a few moments, straightening out his feathers and checking out this new accessory on his leg. I couldn’t tell how old he was specifically; most songbirds can be aged as far as whether they were a baby or a parent last summer because of the way the two age classes moult their feathers (adults generally moult everything, while young birds only replace a subset of their nest feathers prior to migrating). However blackbirds are one of those exceptions to the rule, and all I could say was that I knew he wasn’t a 2008 hatchling.

In the top photo you can see the rusty tips to the glossy black feathers that give the species its name. We tend to think of a lot of species as having “breeding” and “winter” plumages. In most cases, these breeding plumages are obtained through a second moult in the spring. However, there are a few that only have one moult a year, in the fall, generally before they migrate. Their breeding plumage is obtained through the general wearing down of the feather tips over the winter. European Starlings are a good example of this that most people are familiar with. In the fall the birds replace all their feathers with fresh, white-tipped ones. Over the winter the white tips wear off revealing the oily-black breeding plumage. Snow Buntings are another, rather dramatic example of this type of plumage “change”. In the case of Rusty Blackbirds, their rusty tips wear down to form their black breeding plumage. This individual is an adult female that we banded a couple of years ago in the fall. This year’s male is the first that I’ve banded in the spring. Although we see them both seasons, they’re ordinarily a fall capture.

Rustys are just migrants through our area. They do breed in southern Ontario, but only once you get up onto the rocky Canadian Shield. There they favour forested wetlands and swamps, particularly fens, bogs and muskeg. In the recently published Ontario Breeding Bird Atlas, the southernmost record for the species were concentrated around Algonquin Provincial Park, a huge expanse of protected boreal forest about three hours north of Toronto, just a few shades shy of Yellowstone National Park in size. They nest as far north as Hudson Bay, where they tend to breed in muskeg along creeksides. They reach their highest breeding abundance in the Hudson Bay Lowlands, where they can be relatively common, though never as abundant even in their peak areas as Red-winged Blackbirds are south of the boreal forest.

Population monitoring surveys such as the Christmas Bird Count and Breeding Bird Survey have shown a rather alarming trend for the Rusty Blackbird. Since BBS counts started in the 1960s, the species has declined by about 95%. Put in other words, only 5% of the population that existed in the 1960s still remains today. The reason for this incredible decline remains a bit of a mystery, as other species that share their habitat and food preferences on the breeding grounds have not shown the same dramatic trends, although many species that breed in boreal wetlands have been declining to some degree. This may be in part due to acidification of boreal wetlands by acid rain (the limestone rock base south of the shield does a lot to neutralize the acids in the water here, but on the shield the rock is granite which doesn’t have the same properties, so groundwater becomes acidic), or, more recently, chemical or physical changes in boreal wetlands as a result of global warming. But it doesn’t explain the huge decrease in numbers of the Rusty Blackbird.

The answer may instead lie on the wintering grounds. In the non-breeding season blackbirds and related species will congregate to roost in flocks of often hundreds of thousands of birds. They target the waste grain left behind in harvested agricultural fields, but also become a pest to growing crops, particularly ripening corn and sunflower seeds. Blackbirds aren’t protected by the same laws of the Migratory Bird Act that cover other songbirds, and they’re often persecuted as agricultural pests. Surfactants are sprayed on roosting winter colonies that disrupt the birds’ natural water-repellent protection, and the birds succumb to the elements. Despite that Rusty Blackbirds don’t actually feed in agricultural fields very often (even in the winter they prefer wet woods for foraging), they tend to join these communal roosts at night, and so are targeted by the same control methods.

Virtually all species of blackbird are in some level of long-term decline (this includes the widespread and widely abundant Red-winged Blackbird, which is nonetheless declining as well). Why the Rusty should have been so dramatically affected when other birds haven’t been is hard to say, and is part of the mystery behind their population crash, however another likely factor is the gradual loss of wet woodland habitat on their wintering grounds as it’s converted for agriculture and development. It may be that a combination of breeding ground and wintering ground factors are coming in to play to cause the species’ decline.

Because the cause of their decline is still uncertain, it is difficult to form a plan of action to protect the species and bolster its numbers. All we can really do for now is to try to protect the birds on their wintering grounds, maintain the habitat they require there and during migration, and continue to monitor their populations.

It’s sad to think that once upon a time, not so long ago, Rusty Blackbirds may have rivaled some of the other blackbird species in numbers during migration and the winter. Nowadays, it’s a real treat to spot one of these guys as they make their perilous way north and south.

Last week, after my mom and I visited the pond with the salamanders, we stopped by a little creek that was just around the corner. It’s Silver Creek, which is one of the primary tributaries of the Credit River, which itself runs into Lake Ontario. Silver Creek joins the Credit just south of Georgetown, a small town west of Toronto, not far from where my parents live. It runs north through Georgetown, passing the little hamlet of Ballinifad, to its headwaters… or I suppose it’s the other way around, running south from the headwaters, to join the Credit. Either way, it’s one of the primary creeks in my parents’ “neighbourhood”.

The Credit River was one of the rivers that was part of an Atlantic Salmon reintroduction program launched in 2006 due to the quality of its water. The salmon can occasionally be seen migrating up its Silver Creek tributary, and there are signs in areas where the creek passes under roads or through parks indicating that it’s a salmon-spawning creek. It’s a good creek for salmon, with the sort of stony bottoms that create many nooks and crannies for spawning. The same characters that make it good for salmon make it good for other aquatic invertebrates and fish.

We stopped at this beautiful stone bridge and hiked down to the water’s edge. The water comes over the waterfall above and then slows down (a little) in this broader area just before the bridge. The slower water allows creatures to move around between and under the stones where in the faster currents they would be swept away. It also allowed us to step in to the water without being knocked over or our boots filling with water. Or my mom’s boots, anyway - I stood on the bank. Mom waded in and started turning over stones while I held the net a short ways downstream.

It didn’t look like we’d caught anything at first, but as I pulled the net out of the water I could see something large moving amongst the debris. We put some water in a tub and dumped the net contents in. To our surprise, there was a lot more than we initially thought. The large moving thing turned out to be this giant crayfish… in fact, all the moving things were crayfish, of varying sizes. The biggest one was dark, and very big. I can’t believe I didn’t see it go into the net when Mom turned over the stone. Mom decided she didn’t really want to lift up any more rocks.

In contrast, the little guys were quite little, perhaps only 1.5cm (less than 3/4″). There are about 500 species of crayfish in the world, about 350 of which occur in North America, where they’re also called crawfish or crawdad. I had no idea there were so many species of them. The largest is found in Tasmania and may grow up to 40cm (15.5″), the smallest is in the southeastern US and only reaches 2.5cm (1″). On average, most species grow to about 7-8cm (2.5-3″), sometimes reaching 12cm. Our big one was definitely one of the larger guys.

So I don’t know if what I had in the tub were different species or just different life stages. McMaster University lists 9 species occurring in Ontario, of which 6 are stream-dwellers. Many species will reach sexual maturity and mate the fall after they hatch, though fertilization (the female holds the sperm internally over the winter) and egg-laying usually occur in the spring. The female carries the eggs attached to her belly until they hatch 2-20 weeks later (what a time span! I assume that to be a range across species, although water temperature is also a factor). The young stay on the female till after their second moult. A crayfish lives on average about two years.

Crayfish are crustaceans, closely related to lobsters, and are in fact eaten in much of the world. In the US, they’re mostly found on plates in the southeast, prepared similarly to the lobster. Wikipedia makes the interesting observation, “Notably, in Canada the crawdad is considered interchangeable with the potato.” You know… this one seems to have slipped my observation. I use potatoes.

They’re also occasionally found as pets in aquariums. They’re easy to keep, feeding on shrimp pellets, tropical fish food, algae wafers, or other easy sources. They’re also not opposed to taking small fish if the opportunity arises, and may deplete an aquarium’s community rather quickly. Most Ontario species eat small invertebrates or fresh vegetation.

The eyes of a crayfish are on movable stalks that they manipulate to look around, rather than moving the eyeball (or the retina, like the jumping spider). They have two pairs of antennae, which they use for sensing their environment. They breathe through gills that are located on their frontmost legs (which are also used for manipulating food, and are in front of even their large pinchers); you can see them poking out from under his chin here.

After examining our catch and marveling at the size of the big guy, we gently released them back into the water to carry on with what they were doing. Which was probably sitting under a rock waiting for food to float by.

This past week we’ve had beautifully warm temperatures. Up to 20 C (68 F) or more on some afternoons, warm enough to wear a t-shirt (some warm-blooded types might also pull out the shorts or skirt, but I need for it to be at least 25 before I’d feel comfortable with bare legs. Either that, or sitting in the sun with no breeze). These warm daytime temperatures translated into warm nighttime temperatures - a regular occurrence come late May, but in April are worth taking advantage of for mothing. Some early-spring species live for these warm April evenings, and there are many that are more difficult to find as the season wears on.

As indicated last post, early this week I was at my parents’, out in the middle of the countryside. The rural setting there, it turned out, and the relatively diverse habitats on the property resulted in an excellent collection of species observed over the two nights. I ran the blacklight and sheet in the self-portrait of the first photo for a few hours of the evening, shutting down about midnight, and then had my trap set up which ran the whole night. In the pic it’s shown with a blacklight, but I actually had the more powerful mercury vapour bulb in it, which I think helped with the night’s catch. Although the blacklighted sheet didn’t do too poorly, either, really. It wasn’t a wide array of equipment; I also had two more blacklights and an extra sheet to what I put out, but I didn’t want to have to spend a lot of time taking it all down. And, as it turned out, I didn’t really need it anyway.

I ended up with a conservative estimate of 42 species, but there was probably a few more than that - I haven’t yet ID’d all the little small guys, and there’s a good chance that, with my inexperience, I may have written off some stuff as variations of other more common species. This isn’t too shabby for mid-April, as I understand it. Most of these species have emerged from overwintering as larvae or pupae, but a few overwinter as adults. They tend to be the raggedy ones, at least in the spring. Later on in the year the raggedy moths are just worn with age. As I photographed them I released them on to a concrete statue of a raccoon my mom has beside their front stoop. Because they go into a sort of torpid state they didn’t move very far after I placed them on the statue.

This was possibly my favourite moth from the two evenings. I caught five of them total, three on one night, and two the other (it’s possible that one or both of the two were among the three caught the next night, I suppose). It’s a Lettered Sphinx, one of the smaller of the sphinx moths, and fairly blandly coloured compared to many other sphinxes. I loved the way it curls its abdomen up when at rest. I didn’t realize what it was at first, something about photographs of sphinxes makes them look bigger than they really are. This was actually one of the larger moths I caught, but it was still less than 4cm (perhaps 1.5″) long. For whatever reason, these moths only came to the mercury vapour bulb at the trap, I didn’t have any at the sheet.

Another that only came to the trap was this Dogwood Thyatirid. Considering the abundance of Flowering Dogwood, the larvae’s host plant, at my parents’, it wasn’t a great surprise to discover five in the trap over the two nights, either. They’re a pretty nice moth, with a hint of pink to the whiteish patches that just doesn’t really come through in the photos well.

This moth was the opposite, I had five individuals over two nights that only ever came to the blacklighted sheet. Now why would that be? I hypothesize that the blacklight produces a slightly different wavelength of UV light that the different species orient to with greater or less preference. But really I don’t know. This striking green moth is The Joker, and was the very first moth on the very first night. Considering that up to that point most of the moths I’d seen were rather drab, this really made my evening. And, I gather, they only get better from here.

Here’s another one that I was pleased to see. It belongs to the genus Caloptilia, and it’s tiny, less than a centimeter long. This group of moths are among the leaf miners that create trails through deciduous leaves. Like the sphinx moths, when I first saw photos of these guys I thought they were substantially larger than they really are. I thought they were pretty neat-looking, propped up on stilts as they seemed to be. I got one to a sheet last fall, and immediately recognized it (it’s really a rather distinctive shape and posture), but was a little shocked at how tiny it was. Little moths (the so-called micromoths) are tricky to photograph because they tend to come out of torpor very quickly, basically as soon as you disturb them, because their small size means their bodies warm up and resume normal function very quickly. I got two of these guys, both in the trap. The first one I only got a photo of it on the carton it was resting on while in the trap; as soon as I nudged it to try to get it onto something more photogenic it took off. This one is waving its antennae furiously as it contemplates leaving.

This last moth I like because of the intricate mottling and nice mossy-green shading to the pattern. It’s a Grote’s Sallow, and I think I got five between the two nights (what is it about the number five?). Imagine this guy tucked into a crevice on an old, jagged-barked tree trunk. He’d blend right in and you’d never know he was there.

It’s hard to pick just a few species to highlight of the dozens I got, but those were definitely among my favourites. Those interested in checking out more of what I got can visit my moths series on Flickr.

I’ll wrap up with this photo of Lettered Sphinxes snickering behind a Curve-toothed Geometer’s back.

In the last week or so I’ve managed to accumulate quite a backlog of potential post subjects. This is largely because I’ve been out looking at things, rather than sitting indoors in front of a computer, and with spring progressing there’s the potential for a lot of interesting observations. For the same reason that I’m getting lots of good stuff, I’m also falling behind on writing about it - it’s hard to write when you’re not at the computer! I rather suspect that a number of these subjects will be tucked away for safekeeping, to be pulled out at a future date when things aren’t coming quite so fast and furious, or when I’m stuck indoors and haven’t been out to observe much. Julie Zickefoose refers to a person who sequesters posts for lean times (such as herself) as a “blog ant”, referring to the ant’s habit of building a larder in the underground (think of the Aesop’s fable of the ant and the grasshopper). I’m probably more akin to a packrat than an ant - an ant, it would suggest, is discerning. My blogging habit more closely resembles my living habits, where I store things that may come in useful, and when I decide I need something I go back and look over my cache for something that might work.

None of that has anything to do with this post, of course. I’m not writing about packrats, or ants (although I do have some ant photos tucked away). Rather, today’s post is on salamanders, who I’m pretty sure don’t participate in caching behaviour. While visiting my parents this week, my mom and I went out to a local site where she often does pond study field outings with schoolgroups for a local non-profit. It’s a relatively small, but still nice pond, set in the woods back from the road. They usually scoop up some water or sediment and poke through it to see what they can find, learning about the aquatic environments in the meantime. So, to be prepared for what they might encounter, my mom wanted to scout the site and see what was happening.

Along with a handful of different invertebrate species, there were a couple species of frogs heard, and these guys. This is a Red-spotted Newt, a subspecies of the widespread Eastern Newt. A newt is actually a type of salamander, one belonging to the family Salamandridae. The Eastern Newt is the only representative of this family in North America, although they’re fairly widespread on other continents, primarily in the northern hemisphere. There are in fact 10 different families of salamanders, but the other ones we typically think of here in North America, such as the Jefferson’s or the Spotted, are mole salamanders, family Ambystomatidae. Most other salamander families aren’t differentiated by name the way the newts are, however.

The Red-spotted Newt inhabits still or slow-moving waters such as ponds or small streams. They generally prefer moist woodlands, with sufficient debris or submerged vegetation in the water to be able to hide under. The ones we saw were all doing that, they’d cruise languidly along in the warm surface waters (the water was less than a foot deep in the very gradually-sloping pond edges, so it was pretty much all surface water) but as soon as I made an attempt to come in with the net they’d dive under the leaf litter at the bottom. They never went very far, but they disappeared completely.

They eat aquatic insects and insect larvae, small molluscs and crustaceans, and even small frogs and tadpoles. They have an amazing lifespan - females can live up to 12 years in the wild, males up to 15. I suppose this difference could be due to the greater energy demands on a female in creating and laying eggs, versus the relatively energy-”cheap” effort of creating sperm. One study notes that female survivorship from year to year is generally lower than that of males, though a reason isn’t provided.

At just 7-10cm (2.5-4 in), they’re not large creatures. They also aren’t very difficult to catch, once you know how. I started out trying to catch them by surprise by swooping in quickly before they could dart away. Although I successfully got the first one this way, the drag of the net through the water reduced its speed to the point where speed was not the answer anymore; the salamanders were all easily able to dart off before the net reached them. Then I discovered that if you came in quite slowly, they would just sit there, and you could practically scoop them up without them moving.

The species has three life stages. The first is as “larvae”, the salamander equivalent of a tadpole. Eggs are laid in the spring, and take about a month to hatch into young. These are gilled, and spend the next 2-3 months in the water hunting small aquatic prey. They hatch at less than a centimeter (less than 1/2″), but grow quickly; within a couple months they’ve reached nearly 4 centimeters (just under 2″). At this point they metamorphize into their second stage, pictured above.

The second stage is called a Red Eft, and is terrestrial. They can remain in this stage for as many as 4-7 years, depending on latitude and the richness of the local habitat. This is the most commonly seen stage of the species’ life history, likely because of the bright colouration and also their on-land habits. It is in this stage that dispersal takes place, with individuals undertaking long treks of 800m or more where they may encounter new ponds. While their olive-green back is useful for camouflage in the water, on land they have a different strategy. Newts in non-larval stages have toxic skin that is used as a deterrent to predators, but the skin of the efts is ten times more toxic than in the adults. Their bright orange colouration is a warning to creatures wanting to make a meal of them (this special warning colouration is termed “aposematic”).

Of course, I didn’t know this at the time that I was looking at them, and I happily (though gently) picked them up to get a couple of side-on photos that better showed their faces and bellies than a top-down view of them sitting in the water. Fortunately, I suffered no ill effects from the encounter. The back is more toxic than the belly, and despite this defense, newts are often preyed upon; predators get around the toxicity by targeting the newt’s underside. The newts rely on a learned avoidance by predators, where young predators that attempt to take a newt for dinner will remember the distastefulness of it and not try any others. This may result in the loss of one newt, but the protection of many others. Some predator species have an innate avoidance of aposematically-coloured creatures.

The eft I caught was found in the water. This is an unusual spot for one, as they generally stick to the land, and it could be that it was preparing to metamorphize into the third life stage, the adult (perhaps resulting in a lowered toxicity level). Only the olive adults mate, which means that sexual maturity isn’t reached until often three or four years of age, or potentially up to seven or more if the efts metamorphize late. I wonder how old some of the newts I was looking at actually were.

The adults have an amazing homing ability, like that of homing pigeons. Displace a newt from familiar territory and it can still find its way back. It orients using magnetic fields, but also uses its sense of smell (to detect water) and sight (to orient against the sun) to guide it, although in experimental tests even newts with no smell or sight could successfully find water. Displaced newts will automatically orient downhill, which is reasonable, since water usually lies in the lower areas. I wouldn’t've thought that newts would find themselves displaced often enough to have needed to evolve such a complicated system.

I probably saw more salamanders in that single outing than I had in my life prior to that combined. They don’t occur in the ponds on my parents’ property (or, if they do, certainly not in great numbers like they were here, and don’t hang out in the open). I will admit to never having made a special outing to look for them before, either, though. As is the case with so many things, if you actually go looking for something, you can amaze yourself with how common it actually is.