Tuesday, September 13, 2011

Between a rock and a dry place

Rock flipping day this year was like almost every other day for the last couple of months; hot, sunny, cloudless. Unseasonable weather, for BC's climate. I looked up the statistics for Vancouver; the 30-year average rainfalls for July, August and September were 49, 48 and 71 mm; this year, we've had 0, 25, and 0 (so far, for September). The ground is hard and dry; where we are not hand-watering, even the hawkweed languishes.

Would there be anything at all to see under our rocks? I had my doubts.

We were staying close to home, so I took the camera and went across the street to the vacant lot. It has turned brown; yellow-brown grasses, brown dirt, dark brown, dead daisy stalks. The clover is scorched and withered. Only the blackberries thrive; their roots go deep.

The bottom of the pool where crows used to bathe.

But maybe, out of the sunlight, under these rocks, there may be some moisture.

I turned over every rock I came to; dozens of them. Underneath, the ground was hard-packed, dry and barren. No bugs, no worms, no spiders. Just dead roots and dirt.

In a place where someone had piled garbage (which would have contained some welcome moisture) and set fire to it, I flipped a blackened piece of wood, and found the first live thing; a big, healthy-looking spider.

She must be finding something to eat, somewhere.

I had been about to give up, but now I went on with a bit more hope. I found a large cement block with pieces of rebar sticking out, providing me with good handles, and managed to turn it over. And here was a small community:

Fly, with feet tangled in a spider's web, which I broke by lifting the rock. The fly got away. Update:  the "fly" is a wasp, and probably a spider-hunting wasp. See comment by James C. Trager, below.

The web covered the ground, and separately, the bottom of the slab. This spider was between the upper web and the slab.

And this one was hidden in a crack in the soil. Which one did I deprive of a meal?

Stuck on the underside of the slab, I saw a little tube, about as long as the spider, maybe about half an inch. It was slightly ribbed on the outside, completely hollow inside. I touched it, gingerly (it was too close to the spider for comfort); it was hard, and felt like clay.

What made this?

Under another large rock, another big spider, a sow bug, and a tiny snail.

These were under a big sheet of styrofoam.

Centipede. There were quite a few under the larger rocks.

The snail was hiding under a chunk of wood.

A creek traverses the block, going straight across the centre, then angling down the back. The centre part is impassible, completely surrounded and topped by blackberry canes, but along the back, a stand of alders shades it, and the blackberries have left it alone. We've explored it, sometimes walking on boards across the water, sometimes finding only wet mud. There would be other animals there, worms and pillbugs and more, I was sure.

I was wrong. The creek bed is dry. The old pond scum, dry and crispy now, lies pasted to the rocks beneath. There is no sign of moisture, even under boards.

Baked pond scum over dry rocks.

The only animals I found in the creek bed. A few red ants.

On my way back, I lifted a large stone, and was surprised to find rabbit pellets underneath.

How did they get there? The white tendrils are new plants, growing without sunlight.

More rabbit pellets, out in the open, where I would expect to find them.

Next: water makes a world of difference.


  1. I'm celebrating rock flipping week, since I've been so unsuccessful at this time of year. Yesterday my daughter and I hiked a field across the west mesa, and thought, since there'd been rain, we'd find something under some of the wood that someone left behind... certainly there were no rocks larger than the sand. And once again this year we saw nothing. We hope to get down to the bosque this week and flip some rocks down by the river. And yes, water makes ALL the difference!

  2. You were much more persistent than I was and look at your reward. Thanks for sponsoring this fun even each year. - Margy

  3. Hello Susannah -- Your fly is a wasp. I think it's in fact one of the Pompilidae, or spider-hunting wasps, and it may well have been in the process of hunting the spider, rather than actually tangled in the web.

  4. Thanks, James. I'll update the post accordingly.


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