After the wind and rain last week, I noticed lots of leaves lying around on the concrete outside my bedroom door. Except that Calypso the puppy seemed unusually interested in eating them. She eats anything her mouth can reach, but not usually leaves. Then I realized that the little curled up black things were dead worms. Hundreds of them.
Calypso and the magpies were delighted to eat dried up worm carcases.
I’d known that worms tend to crawl to the surface when it rains. In the US they call them “nightcrawlers” for that habit. Every bait store near a fishing spot in America advertises them on amateurish hand-scrawled signs. I’d assumed they were something specially American like chiggers, rattlesnakes, or armadillos, but no, just earthworms.
The story I’d heard was that when it gets wet worms have to climb higher or they drown.
Except it turns out that’s not really true. Curious as to why they were there in such numbers, and only on that side of the house, I trawled the internet and found the Straight Dope site which quotes biologist Richard Wahl of Shippensburg University in Pennsylvania.
It turns out worms don’t drown easily. They’re quite happy underwater, but dry out easily on the surface. So when it rains is the only time they can come up without drying out.
And the reason they come up is to get together with other worms and mate, and make new baby worms. It would be a tight fit to do that in a worm burrow.
So in fact there was an orgy going on outside my bedroom all night long and I had no idea.
Unfortunately for the ones I saw (but happily for the magpies and the puppies) the wind must have dried them out too much to get back to their burrows, or they kept crawling downwind further onto the concrete in an effort to get home.
They looked like introduced earthworms to me, which I know we have around the house. It’s not easy to tell when they’re dried up and blackened. They’re called Peregrine earthworms and are in most places with disturbed soil, like a garden. There’s not nearly enough known about Australian native earthworms, except for the Giant Gippsland Earthworm which has rated its own museum (in Gippsland) shaped like… a worm. The real worms are smaller, only up to 4 metres long. They look like a long squishy snake.
I still don’t have a good explanation about why the worms were concentrated outside my door.
By lunchtime they were all gone, but Calypso was still sniffing about hopefully looking for more.