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Archive for the ‘wildlife biology’ Category

goldenrod galls

Photo by Collin Purrington - http://www.flickr.com/photos/cpurrin1/

It’s March in Vermont, and I sit here typing, snow falls outside. After a few balmy days of rapidly shrinking snowbanks and rising creeks, the prediction for today is 3-6″ of new snow. It makes me wonder about the turkey vultures, the robins, the redwing blackbirds, the green tips of daffodils poking up, even about the moth I saw on the wing last night and the hundreds of spiders crowding the winter-flattened grass near the old pond. That was yesterday, when it was spring. Today it is winter again. But not to worry, it is a fleeting renewal, the last-ditch clutch of a season passing. Summer will come. I think the birds, the spiders, and the moth all know this… and so do the Vermonters, although the weather still galls them.

Some months ago, when the temperatures dipped below freezing, but before layers and layers of snow began their assault on the landscape, I went out and found a couple of patches of goldenrod (Solidago species) and collected a few of the many galls on the stems of the plants. Being a curious person, I noted that the galls showed no sign of anything having exited them, and thought that maybe, just maybe, if I kept them inside and warm for a bit, whatever was due to come out in the spring might make an early appearance for me. I assumed that living inside that hardened gall was a small insect larvae that in the spring would emerge as an adult insect. Well, OK, to be honest I remembered cutting a few open as a kid and finding just such a larvae –  a small, grub-like critter. But I had no idea what the adult version was.

Now, patience may be a virtue and all, but we do have this thing called the internet. It wasn’t long before I knew exactly what to expect coming out of the gall… a goldenrod gall fly (Eurosta solidaginis). This classroom-oriented site by Doug Collicutt was excellent, and this site also had some great photos — most of what I share here comes from these two sites. But before we get into the details, let me finish my particular story.

I set the gall in a mason jar with some screening over the top, and left it alone near a heater. I didn’t keep track of how long it took, but it seems like it was two weeks or so before I walked by it one morning and noted something clinging to the screen on top. A little fly with brown, spotted wings.  I hadn’t really thought that the experiment would work, but there in front of me was a goldenrod gall fly. He wasn’t much to look at really – a little, hunched fly that didn’t seem to move around or fly very well. But still, when you consider that as a larvae he was designed to survive a long winter of sub-zero temperatures in a little brown gall, I was still pretty impressed.

click on any of these for some other photos:

I suppose, when you think about it, any life is amazing. It is a beautiful, mysterious world out there, and our own existence is a marvel in itself. But still, there are moments like this that help one to appreciate the complexity and ingenuity of the world.

Think about it. In the spring, just as the sun is pushing the winter’s snow back and tender new shoots of goldenrods are reaching up into the sun, a little brown fly emerges from a dead, brown gall among last year’s stems. It can barely fly, but it wanders around the goldenrod patch on foot, looking for a mate. It has about 2 weeks to live. If it is a male (like the one in my pictures), its entire mission for its adult life is to find a female and mate with her. He doesn’t eat anything as an adult. He mates and dies, and that is it.

If the fly is a female, once she has mated she finds a growing goldenrod, and using her ovipositor, slips an egg through the skin and into the interior of the plant’s stem. I imagine she deposits a few eggs like this. She, too, does not eat. She simply mates, lays the eggs, and dies.

And the magic begins. Egg hatches to larva. The larva begins eating. The plant senses it, and responds by trying to grow new tissue around it and isolate it. Perhaps the larva secretes a chemical that influences the plant’s behavior, but in either case, the plant fails at its attempt to get rid of the parasite. The little larva gets bigger, and the stem of the goldenrod swells around it, forming a gall. Over the summer, the larva eats and eats, stealing from the goldenrod but not killing it. It spends the summer happily in its gall.

There are threats, of course. Anything that kills the parent plant leaves the little larva without its free lunch. There is no emerging early or crawling over to another plant – its whole life depends on the plant it is parasitizing. There are predators, too. Chickadees know what is in the gall if they can get in. Downy woodpeckers definitely have the means to penetrate the gall. One species of beetle (Mordellistena unicolor) is known to burrow into galls to eat the fly larva, and two species of wasps (Eurotyma gigantea and Eurotyma obtusiventris) use ovipositors of their own to deposit an egg inside the gall. When the wasp egg hatches, it eats the fly larva. And of course there is the curious naturalist who sticks galls in mason jars…

In the fall, as the goldenrod becomes senescent, something triggers the larva to dig itself a tunnel out to the edge of the gall, where it stops just at the skin, and retreats back to the middle. As the goldenrod dies, its tissues become hard, and the larva that misses this step would surely be trapped in the middle of an impenetrable wall of gall. And winter comes.

The goldenrod gall fly larva is one of several species of insects that are able to, as the temperatures drop, produce a sort of antifreeze in their bodies that allows them to survive sub-freezing (and sub-zero) temperatures without tissue damage. It is amazing when you think about it. Anything else would succumb to exploded cell walls and massive damage, but not this little larva. Snow falls, perhaps the dead goldenrod topples and the gall is buried in snow. Maybe it stands through the winter, swaying in frigid breezes. Inside the larva waits for spring.

The warmth of spring triggers a change. Metamorphosis. Inside the gall, the larva enters a pupal stage, and then performs the magic of the insect world (think butterflies) when it emerges as a fly. Unfortunately for the fly, it is still stuck inside a gall. But there is the escape passage dug by the larva in the waning days of fall, and only a thin skin of plant tissue between the fly and freedom. Again magic happens. According to Doug Collicutt, the fly “anchors itself and pumps body fluids into a special portion of its head.” What? Apparently the top of its head balloons out because of the fluids, and this swelling pushes out through the last layer of the plant skin. It waits for its head to shrink and its body fluids to go back to their proper spots, and then the fly emerges.

Wow.

Out there past the window, past the falling snowflakes and the sap buckets collecting crowns of snow, there are larvae waiting for their moment. What a cool world.

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It’s not every day that I see a spotted salamander. As a matter of fact, I spent a lot of time as a kid in the woods around here turning rocks over, poking sticks into holes, and generally looking everywhere I could for things that creeped and crawled. Plenty of red efts, plenty of newts, toads, and snakes. But never a spotted salamander like this one. And maybe for good reason. A quick google of Ambystoma maculatum tells me that the adults spend most of their time nearly underground, in moist, hidden places, eating earthworms and other such things. Only on warm, rainy nights do they venture above ground to go to a mating pond.

A careful study of the above picture though, might leave you wondering just what is going on here. Is that snow??!! Yep, that’s snow all right. This is a photo I took of a spotted salamander as he sauntered out on a fine day in late December, with plenty of snow on the ground. It was a sunny day, but not particularly warm, when I snowshoed up to a small, dark, moving mass in the snow. Stuck in a footprint, as a matter of fact.

There he was, on a groomed cross-country ski trail, stuck in a footprint. I was bemused, to say the least.

What in the world was a salamander doing out in December? I really have no idea. But I do know that due to my inquisitive nature and tireless tracking abilities, I could reconstruct part of the story. For on the uphill side of the ski trail, I picked up the track of the salamander.

How many people can say that they have followed the tracks of a salamander in the snow? Probably not too many. I found myself chuckling at the strangeness of it all while I carefully back tracked the footprints and tail drag of a spotted salamander in December snow. How far had he gone? How long had he been walking? Luckily, after only twenty yards or so, I had my answer. My quarry’s trail led back to a hemlock sapling that was just poking its head up through the snow. On the underside of the tiny trunk was a little tunnel where the tension of the bent twig had probably pushed against the snowpack just enough to create a little salamander highway. And that where the tracks came out of.

Intrigued by the strangeness of it all, I followed the tracks back down to the live specimen, still wriggling in the ski trail. He’d freed himself from the footprint and was now, very slowly, pushing himself forward one push of a leg at a time. The sun was soon to go down, he must have been getting colder and slower. I watched for a minute and he moved barely a foot.

These are the sort of times that can be a sort of test. I am a trained wildlife biologist, versed in the ways of data and statistics and study design. All of which train you to leave things be. To let things play out in a natural way without interference, for the good of impartial observing. And then there is also the school that believes that things happen for a reason, and that you should let nature take its course. That there is a sort of arrogance in thinking that we can change things for the better by sticking our nose into situations like this. I am partial to both of these schools, I will not lie.

But there is this, too. A kinship. I watched the salamander struggling, inch by inch, across the trail. It was now below freezing –  a dangerous time for an ectothermic being. The skies were clear, boding for a hard frost by morning. He was nowhere near shelter. Downhill, and in the direction he was traveling, were a string of beaver ponds that were probably his destination… a winter spent in a sheltering mudbath, I imagine. But I couldn’t imagine him making it that far before the frost crystals began rupturing living cells and putting a solitary end to his efforts.

I considered carrying him down to the pond. Too much? I am no reader of amphibian minds… maybe that wasn’t his destination at all. Besides, what about survival of the fittest and all that? Maybe this creature was not destined to breed again. Who was I to interfere? A leg reached out, the body serpentined and found meager purchase against the grains of snow. Well, I could at least get him off the trail. He stood some chance of being run over by a groomer during the night. My human interference might prevent human interference of another kind.

And so I picked him up and moved him off the trail, to the downhill side. And I hope he didn’t mind that I dug out the slightest of a hollow at the base of a tree for him, and finished by covering him with a handful of snow. Enough insulation, I thought, to help him survive the coming frost. I couldn’t help it.

Did he make it to the pond? Did he survive the night? I don’t know, but I hope so.

What I do know is that some day, years from now, I hope to be out in the winter with a friend, and come across a strange track in the snow. Not a beetle, not a mouse, but something different. I look forward to looking at it, smiling, and saying with confidence, “why, that’s a salamander track,” and then telling this story again.

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Another video… note how the upper juvie decides to gnaw on a stick. These, too, are Mexican spotted owl(ets)…

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I thought i’d share this video i took today of two Mexican spotted owls (Strix occidentalis lucida)… they are, well, doing the owl equivalent of kissing, i suppose. Scientific folk call it allopreening. The male is on the right and the female to the left. As of today, they have two young owls out of the nest (fledglings). While watching (and recording), i could hear the male give some quiet, chittering calls, the female a few rising whistles (contact calls), and an occasionally raspy begging call from the nearby juvies. I’ve got quite a bit of owl photos, video, and information that i will try to get posted soon.

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When you spend your work days in the woods, it’s nice every once in a while to slow down and -on your own time- walk wherever you want and at your own pace. It lets you notice more. And find nests.

There was a junco in a currant bush giving quiet alarm calls as i walked past, and so i detoured a little to see what he was up to. Juncos are ground nesters, so i was curious about the currant bush… a nest up off the ground? The bird flitted away as i looked into the shrub, with no sign of a nest. But then a couple of steps later, a bird flushed out from beneath my feet. Under a fist-diameter fallen branch was a pretty little grass nest with four eggs cradled. My first junco nest of the year.  And not far from camp, either, so one i can check back on.

Late June seems late for a nest… juncos are known for having more than one brood a season. But then again things are a little slow here in the mountains (over 9600′) and it was a long winter. Snow was still accumulating occasionally into May, and the snowdrifts lingered for a long time. The raptors, though, already have their kids out. I saw a Cooper’s hawk out of a nest three weeks ago, and the spotted owls i’m studying this summer already have fluffy little owlets falling out of trees.

A little further down the path, and another bird jumped up from the ground next to me. This one was a little more interesting… I’d forgotten that Townsend’s solitaires also nest on the ground, and usually on rocky banks like those left beside old forest roads. This one was a little bigger, and the eggs were spotted and quite pretty.

Even more interesting, though, was the behavior of the mother… who lingered in a nearby tree and starting making calls that i’ve never heard from a solitaire. It was a raspy, descending call that almost sounded like a red-tailed hawk imitation. One that i ought to file away in the memory banks, but will probably have forgotten by tomorrow.

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Just heard news from the wolverine folk up in British Columbia that Eowyn, the wolverine we captured and collared this winter in the Methow Valley, WA, was found dead up in Canada. Her remains were found buried next to a Doug fir along with some deer remains. The skull was found with deer bones, and the collar was located nearby. Cougar scat was also around and the buried remains also suggest cougar, so the theory is that Eowyn was found on a deer kill and then killed and eaten by a cougar (who may or may not have originally killed the deer).

It’s always sort of sad to hear about the demise of a being that you have touched, and the counterpoint is always that this is good and interesting data. So it is a mixture of feelings. We do know that she was a young wolverine, so I am sure this sort of mortality is not unusual.

Eowyn during capture in February

Eowyn's skull, photo by Eric Lofroth

skull and deer remains, photo by Eric Lofroth

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Canyonlands National Park, at the backcountry permitting desk. I mention to the rangers helping me that I worked in the park, surveying for spotted owls, 15 years ago, and was back to hike Salt Creek Canyon.  They’re interested, and curious about my work and life, so I share a few stories.  It’s nice, every once in a while, to find people that treat me like what I do is special and unusual. Sometimes I forget.

Later, after the ranger-led campfire talk at the campground, one of the rangers approaches me with a couple of friends. He wants me to give a spotted owl hoot and tell his friends about what I do. His wife is there and curious. When I mention that I am driving from Washington, where I was working with wolverines, to New Mexico, where I’ll be working with spotted owls, he turns to a friend and says, “see, he’s living the life!”

And it makes me stop. He’s there with his wife. I can’t reconcile a long-term relationship and this type of lifestyle. He is surrounded by friends. I’m traveling alone and my phone rarely rings. He has a steady job and probably benefits that include health insurance. I haven’t been to a doctor in fifteen years and live in fear of a serious injury or illness. It would bankrupt me. Quickly.

The Life. I suppose I am living it. I see beautiful places and get paid to do things that other people only wish they could do. But then again, there is a price. It is a glorious life, but not an easy one.

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