[milesjag]

I had read rom a fairly antiquated source that the acidity of our rainwater as it runs across the ground and into the worm burrows is quite high (or low?) for earthworms.

Supposedly, this drives a slightly delirious behaviour and results in earthworms getting a little lost and/or stranded, explaining some of the marooning that is often found in the aftermath of a heavy downpour.

As this article failed to mention any of the above, I assume this fanciful theory hasn't survived.