The first was made on the night of May 18, 2013 in Eastham, at woodland Vernal Pond E09. It contains four species of frogs calling. The loudest and most conspicuous is the grey treefrog, a species that most people are not familiar with. It calls occasionally from woodland vernal ponds on warm nights from late May to early July, but is mostly frequently heard in Eastham and occasionally in Provincetown. You can also easily hear the high pitched "peep" of the common and widespread spring peeper. Occasionally, you will also hear the loose banjo string "glunk" call of the green frog. About halfway through the recording, the slow deep grunting call of the American bullfrog can also be heard, but you have to listen carefully.Link here for more information about amphibians at Cape Cod National Seashore.
Frog Call Recordings
Below are links to two separate frog choruses.
Frogs calling, May 18,2013 Eastham