Vernal pools

Springtime brings these seasonal pools, home to frogs and salamanders and a tiny kind of shrimp. The pools dry up in summer and can't support fish; ergo, otherwise-helpless species needing water thrive there. A swarm of tadpoles would be like chocolate pudding to your average perch or bass.

The frogs, both wood frogs and spring peepers, hibernate during the winter under a thin layer of loam or leaves. They survive by icing up. All the fluids in their bodies freeze, but not quite solidly, thanks to an over-production of urea and other antifreezes in the late fall. An excellent tactic for Maine winters. Then in the spring they thaw, migrate to the pools (in most cases the same ones they were born in), advertise for companions, mate, produce eggs, and hatch tadpoles. See the blobs of pudding in the pictures below.
The males are the ones doing the advertising, of course. We heard them peeping last night as we drove home from an anniversary dinner in Rockland, an absolutely distinctive sound, like no other, like pure joy sent up to heaven from earth. It's just chemicals, I know, but I'd like not to believe that, especially in the face of evidence like 23 joyous years of migrating to Maine with my own wonderful companion.