Thinking of Frogs

Early on Saturday morning we had the first thunderstorm of the season, which caused many wood frogs, spring peepers, and chorus frogs to start calling. It is very early in the season for chorus frogs, but the early start to the breeding season is probably related to the warm weather we have had recently. In any case, the signs are in the air, and we are busy preparing for the crawfish frog breeding season.

Crawfish frogs are state endangered in Indiana and widely declining in many parts of the country. These large, spotted frogs are inhabitants of wet prairies and grasslands of the central U.S., where they spend most of their lives in the burrows created by burrowing crayfish. They rarely venture forth, apparently waiting near the entrance of the burrow at night to ambush their prey. They are specialized inhabitants of shallow, ephemeral pools (perhaps historically many of these were created by wallowing bison—at Big Oaks quite a few are bomb craters). They do not succeed in reproducing when ponds stay wet through the winter, because some frogs, such as green frogs, have tadpoles they overwinter and become voracious predators in spring—eventually fish can get into permanently wet ponds. In March and April they emerge to breed.

At Big Oaks, we have managed to increase our population of crawfish frogs over the years, in part by creating many new ponds with water control structures which allow us to drain the ponds in fall let them fill with enough water in spring to last through their metamorphosis in the summer. Right now we are plugging up the water control structures to allow the ponds to flood, but a lot of the drainage systems need repairs, such as digging out sediment around pipe openings or putting in and compacting fresh soil to prevent leakage. It is a muddy work, but a lot of fun!