April is usually the month when you can count on hearing the first frogs of spring. Sometimes, they start in late March, but this has been a colder spring than usual. Even though there was a light coating of snow on the forest floor this morning, there have been a lot of singing frogs heard during a mild period around the 13th and 14th; the temperature came close to 80° on the 14th. You only need temperatures of 50° or so for the first frog species to emerge and start singing.
One of the most common frog species first heard is the spring peeper (Pseudacris crucifer). A spring peeper makes a singular tweeting sound that resembles a bird peeping every second or so. Where there is one spring peeper, there are usually many; when the males are calling at once, it is a chorus. The sound of spring peepers in a wetland can carry for 100 yards or more. They may be easily heard, but they are difficult to see. They are only one inch long and blend in well with their surroundings. A few individuals may be found out of the water, next to the wetlands; otherwise they are hidden at the bases of vegetation near the edge of the water. A few pair may be spotted in the water in amplexus (coupled). The spring peeper can be found in almost any wetland environment, including ditches that have standing water. The ditches may dry out during the summer, but they need only a few weeks for the eggs to hatch and the tadpoles to develop into froglets, when they can leave the pond.
Another singer heard around the same time is the wood frog (Lithobates sylvaticus). These frogs are not as widespread as spring peepers; they are found in vernal ponds. Like the spring peeper, the males start calling soon after the pond ice starts thawing, and it’s not uncommon to see calling males sitting on a left-over ice shelf next to open water. The call of a male wood frog resembles a quack, and several calling at once will sound like a flock of ducks. Wood frogs will stop calling if they spot movement along their pond, but if you stay still for a few minutes, they will soon resume calling. Wood frogs tend to breed in a short period of time; in a couple of weeks, they have completed breeding and have dispersed from the pond. After breeding, wood frogs move to forest habitats away from water. A silent pond and light-colored egg masses will tell you that breeding is over for that pond. The young will likewise disperse from the pond as soon as they develop into frogs; a few may cover long distances across the forest floor and find new breeding areas away from their natal pond.
Spring is the renewal of life in the wild as birds are heard calling, woodpeckers increase their drumming, and for the wetlands, the sounds of the frogs calling for mates to start anew the cycle of life. To hear a single spring peeper and a pond full of wood frogs, see below.