The third member of the nearly frozen pond trio is the Spring Peeper
which is as small as the Western Chorus Frog, but is marked with an "X"
on its back instead of three dark lines. Spring Peepers have tan, brown,
gray or olive body colors; the cross-mark is darker than the body.
Spring Peepers often call with Western Chorus Frogs during the late
March to early April breeding season, but their calls are so different
that they can easily be distinguished. Males have large vocal sacs under
their chins. Pumping in a full charge of air, each male emits a mighty
"peep." A pond full of Peepers sounds like sleigh bells and can be almost
deafening to the observe. Sometimes males call from under clumps of grass
or in crevices in the earth which magnify the call. This creates an effective ventriloquism; the frog sound seems to come from somewhere other than where the frog is. The easiest way to see calling males is to look for the vocal sacs inflating and deflating. Each vocal sac is about the diameter of a 25-cent piece and is very shiny.
Ellin Beltz firstname.lastname@example.org October 26, 2008