I took some pictures today, in the order shown here. I pushed some of the piles aside and exposed various worms in some of those holes and in some of the overturned piles. The holes that look bigger are just close-ups of the previous one. I don't know whether these animals are at all responsible for making the holes or the piles of sticks, or whether they're just taking advantage of the situation. I tried to look up this phenomenon on the internet, but haven't found a definitive cause yet.
One interesting discussion was at http://blogs.exploratorium.edu/whyintercept/2011/03/30/earth-worminess/, but it didn't really explain what kind of worms do this, nor how.
It's hard to imagine an earth worm pulling sticks down into its hole. Since it seems like I've only noticed these piles after hard rains, I thought that maybe the worms burrow up during the rain, and the sticks get washed into the hole by the water flowing down the trail. But I can see the holes in that argument too.
Update, May 20, 20011:
- This article on no-till farming explains that earthworms actually do pull sticks down into their holes.
- Great Lakes Worm Watch explains: "Nightcrawler middens, are distinctive piles of cast material around the openings to their burrows. These middens are usually about 1-5cm in diameter and 1-3cm in height with a burrow hole (2-4mm in diameter) near the center. The burrow entrances of middens also often have large numbers of leaf petioles or fragments of leaves sticking out of them. These got stuck there as the nightcrawler inhabitants attempt to pull leaves down into their burrows."
These are night crawler midden mounds. Yse worms are doing this work most often after it rains. See my YouTube channel USASTEAMcom for videos of worms moving objects. Brad Griffith Sequim
ReplyDeleteOh my god. I’ve been obsessively searching the internet for two summers now trying to find what is creating this same situation in my garden area here in Alaska. I don’t know how I didn’t find your blog until now. THANK YOU, you have solved this mystery. However I did find two strange cocoons when (very scientifically with a twig) excavating some of the weird little mound holes and I haven’t been able to determine what they are just yet. But at least those will eventually hatch and I’ll have an answer lol.
ReplyDeleteI'm from Southern Alberta, Canada. Night crawlers were brought here for fishing bait many decades ago. My yard seems to be like ground-zero. I find these worms to be extremely detrimental to soil and plants. They turn soil into hard clay in areas not tilled or disturbed. They make hard lumps everywhere, pull twigs and leaves into burrow openings, which anchors their 'paddle like ends' when they come out at night. They can be stretched out for several inches and withdraw in less than a 'blink'.
ReplyDeleteI've seen them eat root hairs from shrubs, and have literally killed plants when they crawl through the holes on planter bottoms. For some reason, ants seem to be compatible?
These worms are NOT our friends. There's no natural balance and they survive cold, drought etc.