Amphibians in April

     Several kinds of amphibians live in southeastern Pennsylvania, including frogs, toads and salamanders.  The word amphibian means "two lives", which many amphibians have, one life in water as youngsters and the other on land as adults.  Most amphibians have smooth, moist skins which they keep that way by living in constantly damp habitats.  Being small, camouflaged and hiding in moist, sheltered niches, amphibians are not at all obvious to us, though a few species with abundant numbers are noticeable by sound or sight at times.   
     Wood frogs and spotted salamanders spawn in temporary pools of rain water and snow melt on many dead-leaf carpeted woodland floors in this area early in March every year.  And right after producing eggs in floating, gelatin masses of hundreds, males and females of both species leave those puddles and retreat back under the dead-leaf coverings on forest floors where they hunt invertebrates during the warmer months.
      Meanwhile, the young of both species are left to raise themselves, often by the thousands in some temporary, woods puddles.  They hatch sometime late in March, depending on the water temperature, and the dark tadpoles of wood frogs consume algae and decaying leaves in the pools and grow legs and lungs in preparation for life on land.  Spotted salamander larvae, which hatch with four legs, consume aquatic invertebrates and grow lungs for life on the ground.  
     Both these species of young amphibians are unknowingly involved in a race against the ponds drying out anytime from April into summer.  During dry years when there is inadequate rain, the puddles might dry out before the young frogs and salamanders are completely prepared for life on land.  There may be few or no new wood frogs and spotted salamanders to replace the deaths of their relatives in the woods.  But during years of adequate rain, hundreds, even thousands, of young wood frogs and spotted salamanders develop legs and lungs in those temporary pools and finally take their place under the moist, dead-leaf carpeting on forest floors, replacing those of their relatives that died.
     By late March and through April, male spring peepers, American toads and pickerel frogs emerge from hibernation and begin calling at dusk for mates to join them in shallow water to spawn.  In many different ponds and wetlands locally, hundreds of peepers peep shrilly, while scores of toads emit whirring trills that last about six seconds each, and scores of pickerels utter deep, one-second snores, all species pleasantly shattering the twilight and nights of April.  It's a joy to many people, including this one, to hear the timeless, simple choruses of these tailless amphibians, especially the peepers and toads calling together, on April evenings.  Listening to those amphibian concerts is like stepping back eons of time, particularly at night when little is seen and imaginations run wild.     
     Toward the end of April, green frogs, bull frogs and common toads emerge from their winter's sleep and begin feasting on invertebrates, the frogs along the edges of ponds and the toads in damp fields at night.  But these tailless amphibians don't start calling for mates until early May and into June and July.  Male green frogs belch and twang loudly from pond and wetland edges.  Their simple calls can be imitated by the human voice well enough to get them to answer someone imitating those gulps and plunks.
     Bull frog males sound like the lowing of cattle, hence their name.  As with male green frogs, if one bull frog calls, others hear him and add their lowing to the ensuing bull frog chorus along the shores of many ponds.
     Common toads have a call that sounds like a nasal "wwaaaaahh" and only lasts a couple of seconds.  Like American toads, male common toads call while sitting in inch-deep water on the shore of a pond. 
     All these frogs and toads are heard far more often than they are seen.  But their voices are a major part of spring and summer evenings, adding more charm and intrigue to the local landscape.  Try to get out to hear some of these amphibians, from a discrete distance so as to not disturb them.