April 1, 2008; March 18, 2009; March 22, 2010; April 3, 2011; and March 14, 2012.
You probably recognize these as the five most significant dates of the last five years. Well, OK, the most important days in the life of a wood frog. OK, OK, the most important five days in the life of a wood frog in the vernal pond near my house.
The first time I heard the wood frog (Rana sylvatica), I thought, “Oh no, someone is strangling ducks in the pond!” Alas, it was not ducks, it was the unusual call of the male wood frog announcing to the female wood frogs the start of their explosive breeding season.
For me, the call of the wood frog represents the true sign that spring has arrived. Like the spring peeper (Pseudacris crucifer) and the grey tree frog (Hyla versicolor), the wood frog is freeze tolerant, releasing glucose (sugars) to protect vital organs during Winter. When the temperature rises above freezing, the wood frogs defrost and head off to breed. The wood frog and the spring peeper are the first frogs that I hear each spring, usually within a few days of each other, but the peepers’ peeping does not peak for a few weeks, while the wood frog chorus is practically immediate.
The wood frog has many amazing characteristics, but the most amazing one that I have observed is their patience. Wood frogs are explosive breeders. This means that the breeding takes place over a very short time, from a few days to a few weeks depending on weather conditions. The females lay their eggs at the same time in the same location. This large mass of eggs contains a few hundred to a few thousand eggs. Presumably, the wood frogs do not want anyone or anything to know where their egg mass is for obvious protection. No matter how silently I approach the pool, under the cover of darkness, when I get about 50 yards from the water, the frogs all go silent. Quietly, I slip into the edge of the water, make my way to a clump of sedge and lean against a tree. There I stand, unmoving and silent. Fifteen minutes. Thirty minutes. Forty-five minutes. No matter how still I remain, the wood frogs do not make another sound. They will outwait me. Usually, I am forced to give up and leave the water without seeing a single frog.