One might think a rainy day is the perfect kind of day to sit inside, curl up in a chair with a good book, sip some tea, and maybe take a nap in the process. Of course, it is. But it’s an even better day to head out the door and into the woods. And so I did.

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I learned an interesting thing in the process as I walked along our cow path searching the bark of one tree after another to see what I might see.

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The back sides of the trees were fairly dry as indicated by the lighter gray color. That didn’t make sense until I realized that was the southwestern side and today’s storm is a good ole New England Nor’easter. I suspect as the wind increases tonight, all of the bark will get wet.

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With that understanding, I continued my search and finally was rewarded with a sighting upon a Red Maple that had long ago suffered a wound. Yes, that slug was the object of my attention.

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When not consuming a garden, I find slugs to be fascinating critters. Classified as gastropod mollusks, they are in the same category as snails. The main distinguishing factor is that a slug lacks the external hard shell of a snail. Mostly nocturnal, they tend to feed at night and have a preference for dark, cold, and moist hiding areas during the day so that their skins do not dry out. But on a rainy day–ahhh.

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Watching one move requires patience. Being diverse feeders, their diet differs depending on their types. In general, some tend to feed on plant matter or fungi, while others are predators feeding on different small organisms. I suspected this one was finding small organisms to dine upon as it glided ever so slowly on its slimy ‘foot,’ a long sheath of muscle on the underside of its body. The muscular ‘foot’ constantly oozes a slippery mucus to aid movement, which is why slugs leave a slimy trail in their wake.

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Finding one slug was certainly not enough, so I rolled a few logs. Did you know this? Slugs are hermaphrodites, meaning they are born with both sets of sex organs and are able to lay eggs after mating.

In optimal conditions, slugs may lay clear, jelly-like eggs every warmish month, which hatch into baby slugs after around two weeks.

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I also checked many, many more trees as the raindrops increased in intensity.

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Unlike watching a slug’s movement, which can take such a long time, try capturing the travel route of a rain droplet. If you look closely, you might spy one about two inches down and two inches in on the upper left hand side of the tree.

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Don’t blink or you might miss the action as the droplet falls. And just as quickly a new droplet forms.

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Where exactly did the drop land? Upon a pile of foam. Here’s how it works. As the rainwater flows down the trunk, it dissolves chemicals from the bark. In the process, it changes the surface tension of the water so that as the droplets drip toward the base of the tree, air is introduced due to the turbulence and foam forms because the surface tension is altered.

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I found it on pine and oak, but also near the base of Eastern Hemlock and Red Maple. And of those various forms, my favorites were a much looser structure that reflected rainbow colors in an almost hexagonal prism.

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This rainy day . . . of slugs (for I did find a second one so I can use the plural form, and my first had moved all of two inches when I returned to it an hour later) . . .

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turned out to be also a day of suds, and for both I gave thanks.