Posts Tagged ‘ponds’

DIY underwater webcam

One of the fun parts about field research (and much lab work too) is making equipment for really obscure purposes on a tight budget. My pond enclosures, for example, are made of window screen sewn together with fishing line. This year the DIY component of my experiment had slightly wider applications and could potentially be a fun thing to do if you have a fish tank or a favourite local watershed that you want to film.

I originally decided to film the stickleback mate choice trials so that I could figure out how long to run them for. Last year, I had no fish spawn in the first 30 minutes, but more than expected spawn after 24 hours (including way more inter-species mating than there should have been). I decided to try four-hour trials but hoped that I could eventually cut it to two hours if most spawning took place before then. Since I didn’t want to disturb the fish during the trial, filming seemed like the best option. Filming the trials would also potentially give me more data—I could record not only whether spawning took place but when, and how many times the female checked out the nest before deciding to spawn. So I needed to figure out a cheap way to waterproof a webcam and anchor it next to a nest.

My supervisor found this tutorial. It’s a pretty neat camera housing design, really cheap, and surprisingly easy to do—I used a Swiss army knife for virtually every step. I bought the cheapest webcams I could find, and used some old body lotion containers. I cut a window in each of these and covered it with a piece of an old CD case. The trickiest part was rewiring the webcam – I had to make a hole in the housing for the cable to go through, then cut the cable, thread it through the hole, and reattach all the wires. To keep the lens from fogging up, I put some silica gel inside the housing to absorb moisture. I glued everything up with aquarium silicone (which woudn’t leach harmful chemicals into the pond). Since the housing was full of air, it was positively buoyant, so I attached them to dive weights to keep them on the bottom of the pond. The cameras were connected via a bunch of boosted USB cables (actually the most expensive part of the project!) to a laptop on shore.

The results were mixed. The cameras worked as well as could be expected (they were, after all, dirt cheap). But positioning the camera so that it faced the nest was extremely difficult. I tied a piece of fishing line to the housing so that I could move it around without pulling on the cable (which would dislodge the silicone and cause a leak), but this often ended up slipping off the camera—so I had to pull it up by the cable anyways. Fortunately, the first few times they leaked I was able to dry everything out and reuse them. Eventually, however, the cameras just died. Possibly next time I should try drying them out in a jar of rice instead of just air-drying. (“Next time”, yeah right.) I also probably could have come up with a better way to attach the weight and fishing line, but I decided not to worry about it. The positioning problem made it clear that I wasn’t going to get much data from the videos, so I changed my goal to just trying to get some decent video I could show in a presentation. (Research is all about redefining goals, a.k.a. lowering your expectations.)

I did get some statisfactory footage. Here’s a benthic male nesting in the open (ish). I ended up not using this trial because the female wasn’t actually ready to spawn, and, as you can see, the male’s nest is actually in sparse vegetation that I had overlooked when I put him in the enclosure. It shows some of the nesting behaviour well, though. The male is in bright nuptial colouration—blue body and iris with a bright red throat—and he pokes around at the nest and occasionally deposits spiggin. At about the 1:50 mark, he also swims through the nest, which is pretty adorable. (Oh, and there’s a backswimmer kicking around in there too.)


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Pond withdrawal

The minor blog hiatus of the past two weeks was due to my defending my Master’s thesis. Take that, science!

This past week, I officially ended my habitat choice experiment (explained here). Yes, I continued this experiment virtually up to the day of my defence; don’t ask—like all experiments, it did not go smoothly. Anyways, I removed all the remaining fish—which will be used by other grad students for their own projects—from my ponds, took out the enclosures, washed them, and packed them away for some future scientist’s use. It was a little sad. But it was impressive to see how well those enclosures held up after more than a year exposed to the elements. What was even more impressive was how they became part of the pond environment: there were plants and algae, especially Najas flexilis, growing up through the mesh, so that the bottom edges of the enclosures were almost sewn into the pond bottom. The enclosures were also crawling with tiny tree frogs, as well as a legion of baby water scorpions, so I had a lot of fun just picking creatures off the enclosures as I pulled them out of the water.

The frogs are funny creatures: being tree frogs, they’re mostly terrestrial (okay, arboreal), and so not actually all that keen on being in the pond once they’ve metamorphosed from their tadpole form. They don’t swim very well at all—as soon as they stop actively propelling themselves, they float upright (it seems as if their heads are more positively buoyant than the rest of their bodies). And when they’re in open water they make a beeline for the nearest shoreline-like objects. This resulted in many frogs trying to climb up my legs.

Here’s a gratuitous frog picture. This little dude was sitting on top of a pole that was propping up one side of the enclosures. I thought this spot looked too hot and dry for a frog, but it seemed perfectly happy there—this funny hunkered-down pose, with legs tucked underneath the body like a sleeping cat’s, is their favoured posture.

So I guess my “Pond county almanac” is coming to an end. I have a couple of follow-up posts lined up, but I’ll no longer be at the ponds on a regular basis. This is a weird feeling, especially since it feels like summer’s only just started—as I’ve mentioned before, we’ve had unseasonably cold and wet weather this year. I think this has translated into fewer insects emerging from the ponds, although there are other variables that could explain the pattern I’ve seen. Here’s a picture of a section of enclosure from roughly this time last year: it’s covered with insect exuviae. When I took them down, there were about half as many exuviae as there were last year.

And finally, what the hell, here’s another frog picture. They’re so darn cute.

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Snake in a pond

Today was my idea of a lovely Sunday: I unexpectedly had another female stickleback ready to spawn, so I was able to collect one more datapoint. On top of that, it was gloriously sunny (finally). Better yet, the fish spawned quickly, so I didn’t have to wait around for two hours to collect my datum.

But the best part: as I was preparing to recapture the experimental fish, up swam a garter snake:

Snakes are quite good swimmers, and this one had probably slithered in to the pond to snack on the frogs which are ridiculously abundant right now. They seem to move through the water exactly as they’d move over solid ground, and leave hardly a ripple in the water. But it looked like this snake—a garter snake*, probably a western garter snake, Thamnophis elegans—was having a hard time climbing back out (again, the steep, smooth plastic sides of these ponds are not very-wildlife friendly), so eventually I fished it out. Then I and several other researchers there gawked at the poor thing for a while.

I should probably add a disclaimer here: if you find a snake, please don’t pick it up. That is (a) the one way to guarantee that it will bite you, though one this small won’t break the skin, (b) also a good way to get yourself sprayed with stinky stuff, and (c) not very nice for the snake, which will be stressed out and potentially injured if not handled properly. I do actually have considerable snake-handling experience so just do as I say, not as I do. (Unless you are in Guam and find a brown tree snake, in which case kill it.)

*Garter, not garden. There is no such thing as a garden snake.

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Posts have been a bit sparse this month and short when they do appear because I’m preparing to defend my Master’s thesis. I am, however, still working at the ponds every day, so here is a little update.

This summer, despite being one of the hottest on record in the rest of Canada, has been cool and wet here on the west coast. While I find this annoying in some ways, it’s useful from a science standpoint because it’s extending the stickleback breeding season—the shallow water where my enclosures are set up doesn’t get so hot that the fish die. Thus my experiment is continuing for a few more weeks.

The sides of my enclosures are speckled with insect exuviae—mostly damselflies, but increasing numbers of dragonflies, especially the big Aeshna multicolor, as well. The killdeer have hatched another batch of chicks and recently a mother duck showed up with ducklings. (They seem to have left; probably because the plastic sides of the ponds make it very difficult for the ducklings to get out of the water.) There are still tadpoles of all sizes, and the largest of them are now full-grown frogs.

The Scotch broom and many of the native wildflowers are done flowering. Now, some white sweet clover—another invasive legume—is dominating the landscape. I’m not going to be trying to remove it: it can grow back from cuttings, and I don’t really have the time.

Inside the enclosures, especially those with other vegetation, filamentous green algae has been growing rapidly. The stickleback are good at keeping the areas around their nests clear, but it was threatening to cover some enclosures, so I’ve spent a lot of time scooping it out. Fortunately, I seem to have an ally in some chironomid (non-biting midge) larvae. They are tiny little bloodworm-like things, except green rather than red (actually, I think they’re transparent, and the green is the algae in their guts), that encase themselves in a layer of slime and graze on the algae. They’ve managed to control the algal bloom in several enclosures.

My favourite moment this week has been the appearance of fledgling barn swallows. The picture above shows two of them perched on the ropes that hold up my enclosures. There were three at one point, all huddled together, while one of their parents wheeled around a chirped at them. One by one, they all eventually took flight.

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…of the first of this year’s tree frog cohort leaving the water, a poetry translation break.

senem in lacus

ranunculus saltabat—

sonitus aquae!

I’m being a bit self-referential here, because this is my (rather hasty) Latin translation of a classic haiku, suggested by Wickedday‘s delightful and wistful poem, inspired by my original frog post.

I was hoping to arrange matters such that the haiku would also scan as a hexameter, but that didn’t work. (Anyone who can improve on this, or who has corrections, please chime in!)

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Watch wildlife long enough, and you pretty quickly lose any illusions you had of nature being harmonious or in any sense just.

Last weekend there was a brief but torrential downpour, and any odonates (dragonflies or damselflies) that were moulting at the time, and thus still soft-bodied, were either killed or injured. Many survived but with crumpled wings, legs, or abdomens. They won’t be able to fly, and now they’re sitting on the edges of my enclosures, starving to death.

This is one of the more intact dragonflies—one hindwing didn’t open, one forewing is bent, and you can’t see it from this angle, but there’s also a scratch on her left eye. I’ve identified her as a blue-eyed darner (Aeshna multicolor) based on the two straight-edged, diagonal, unbordered stripes on her thorax. (Only the males of this species have blue eyes—I have yet to spot one.)

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Research goes slowly yet the hand-in deadline for my thesis advances fast. Time for another post where I try to distract myself, this time with pictures of pretty things.

I found this lovely moth, a black-and-neon-pink cinnabar moth (Tyria jacobaeae), outside the lab at the ponds today. In identifying it, I realized that I’d seen its caterpillars last year. The moth is native to Europe and Asia and was introduced to North America to control ragwort (Jacobaea vulgaris, hence the moth’s species name). They acquire toxins from the plants they eat, which in turn make them toxic to predators—hence the wild colours. Here are two views of the adult moth, and a picture of the caterpillars:

There are also a ton of wildflowers in bloom right now. I’ll show more pictures once I’ve identified more of them (read: gotten the botanists in my life to tell me what they are), but here’s a preview.

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