One nice aspect of our office on Bayshore Road is it's sufficiently close to the Baylands that I can get out on occasional walks. One day recently I had a burrito lunch walk, ending up on a wooden platform extending a little ways over the water at high tide. Everywhere under the shallow surface were snails, slowly moving about.
Seeing snails was nothing new, but this time I stayed in one place long enough to see something different. The seemingly-random, slow snail movement was actually converging on a submerged tidal channel, where a higher concentration of snails were already moving downstream - thousands of snails as far as I could see, in some kind of migration.
I don't really know what was going on. It was shortly after high tide, so the snails may have just been moving to keep below water level. Or maybe it was a real seasonal migration of some type. Still, I felt lucky to have this mini-revelation of a natural process going on in a place I had been to dozens of times before.
Another reason to keep in mind the value of easily-visited, local open space, giving us a chance for revelations that we don't see in our first visit.