Fast forward a month or so to Feb. 20. There is a really obvious population boom at night when they are out. Photo of the right 60% or so of the pot, showing around 40-50 individuals.
Left half of pot. So probably 80-90 slugs on the whole soil surface (not counting any that took the night off).
One of the more interesting things I learned from this experience is that these slugs come in different color morphs (dark vs. light).
Photo from March 6 shows they're growing in individual size. Quite a few of them are around an inch in length now.
There seems to be a continuous range in dark/light morphs, in this March 7 photo.
But my subjective experience, over all, is that most of them look basically "white", and a minority (maybe 10-30%) are "dark" like the one on the right.
In this March 7 photo (daytime), you can see they're running out of space to squeeze in along the edges of the mulch. I realized later the mulch was stuck pretty firmly to the soil, so very few were actually managing to hide underneath the mulch.
