Most of us are familiar with the American toad’s breeding call – a long trill that advertises his presence to potential mates in the area. However, American toads have three other calls, as well. A shortened version of the courtship trill, which sounds like a chirp, is given by male toad with its vocal pouch just slightly inflated. A second, release call, is often heard when a male is clasped by another male. (If you want to hear it, just pick up a male toad during the breeding season – it will vibrate as it chirps right in your hand. The combination of the call and the vibrations usually causes a clasping male to release his grip.) A fourth call, which has been recorded in the lab but not in the field, is a series of quiet clicks given by the male while clasping a female.
If you’ve spent time at a pond recently and heard what sounded like someone snoring, you weren’t hallucinating! Male pickerel frogs have started calling to attract mates, and each species of frog, just like birds, has its own distinctive call. Spring peepers peep, wood frogs clack and pickerel frogs snore. Their snore isn’t long – it only lasts a second or two — but it’s unmistakable. Pickerel frogs call from under water, as well as on top of mounds of vegetation, so if you hear one and then search for it, it’s very possible you may not find it. (My sincere apologies-computer failure prevented me from posting on the previous two days.)
“Peeps” and “quacks” fill the air these days. How is it that these frog calls travel so far? It’s all thanks to a thin membrane , or sac, that most frogs have. Note the single inflated sac of the spring peeper, and the paired sacs on either side of the wood frog’s head. These vocal sacs act as resonating chambers, causing the male frog’s mating call to be amplified and carried far (some species of frogs can be heard over half a mile away). Most frogs have one of three basic types of vocal sacs: a single throat sac (the most common), paired throat sacs (partially separated by connective tissue) and paired lateral sacs (completely separate chambers on either side of the head). Vocal sacs are outpocketings of the floor of the frog’s mouth. When calling, a frog closes its mouth and nostrils, and expels air from its lungs through the larynx and into the vocal sacs. The vibrations of the larynx emit a sound which resonates within the vocal sacs. The frog continues calling as muscles within its body wall force the air back and forth between the lungs and vocal sac. The thickness of the vocal sac wall in frogs varies. Typically, small frogs that call in the air (spring peeper) have thin vocal sac walls, whereas those that call in the water, particularly large species (green and bull frogs) often have thick-walled vocal sacs that appear swollen, not inflated like a balloon, when filled with air.
Common Mergansers are primarily fish-eating ducks. Young mergansers require over half a pound of food per day during their first summer, and often supplement their fish diet with insects, mollusks, crustaceans, worms, frogs, small mammals, birds and plants. The pictured immature Common Merganser had just downed a crayfish when it spotted a frog which it succeeded in catching and eventually swallowing.
Like all amphibians, toads breathe through their skin as well as with their lungs. When a toad is inactive the skin usually absorbs enough oxygen to meet its needs. During and after activity a toad often supplements its supply of oxygen by actively breathing air into its lungs. Unlike mammals, amphibians do not make regular and rhythmic breathing movements but bring air into their lungs spasmodically as the need arises. Air enters the toad’s mouth through its nostrils, and by raising the floor of its mouth, the toad forces the air into its lungs. (Photo is of an American Toad.)
Although Spring Peepers emerged from hibernation about two months ago, on warm nights the males are still advertising for mates and will continue to do so into June. Let your ears guide you to the peepers as they call repeatedly, often while perched on low vegetation near water. Armed with a flashlight, look for the movement of their vocal sacs as they inflate and deflate as the peepers sing.
Under the stealth of a rainy night, subterranean-dwelling spotted salamanders migrated to their ancestral breeding pools this week. Groups, or “congresses,” of males gather, followed by females. Once a female locates a congress of males, she eventually pairs up with one of them. The pair of salamanders then engages in a courtship dance ending with the male depositing a tiny white packet of sperm called a spermatophore on the bottom of the vernal pool. If he has sufficiently stimulated the female, she picks up this packet into her cloaca, or vent, and fertilization takes place. The next morning the only sign that spotted salamanders have been and gone are the unclaimed spermatophores scattered on the leaves that lie on the pool bottom.
I heard my first peeper on March 18th, roughly two weeks earlier than in past years. These tiny members of the treefrog family begin mating rituals shortly after the end of hibernation. The males gather at small pools by the hundreds. Each male establishes a small territory and begins calling the familiar high-pitched “peep” quite frequently. The louder and faster he peeps, the better his chances are of attracting a receptive female. Males usually compete in trios, and the male with the lowest-pitched call usually starts the vocal competition. If you look closely at the peeper in the photograph you can see some snow fleas hitching a ride.
You may well have heard the single “peep” of a male spring peeper emanating from the woods recently. It does seem odd to hear this call now, often far from water, as we associate it with spring courtship. This phenomenon occurs so regularly in the fall that herpetologists have given it a name – “fall echo.” They speculate that peeper calling is spurred by light and temperature conditions, when fall climate conditions are similar to those of spring.
Next to the green frog, the pickerel frog is the most abundant frog in New England. It is often confused with the northern leopard frog, which it closely resembles. The spots on a pickerel frog’s back are squarish and aligned in rows, whereas the leopard frog’s spots are rounded, and randomly scattered over its back. In addition, the male pickerel frog has bright orange on the inner surface of its hind legs, which the leopard frog lacks. The pickerel frog is very sensitive to pollution, so its presence is indicative of good water quality.
Because of all the rain we’ve had, little orange salamanders are everywhere! These red efts have a fascinating life history. Eggs are laid in a pond,
and hatch into larval salamanders referred to as eastern newts (previously
called red-spotted newts). Eventually the larvae shed their gills, grow lungs, turn reddish-orange and crawl out onto the land, where they are called red efts.
After spending three to seven years on land, they turn olive-green
(still maintaining the red spots they possessed as red efts) and return to the
water, where they spend the rest of their lives and are referred to once again as