Herpetofauna: One Life's List

Hyla versicolor - Hyla chrysocelis
Gray Treefrog

Union Co., Illinois
May 1986 (versicolor)

Rockingham, North Carolina
May 1998 (chrysocelis)

Identical in every way but two, these frogs are.  One difference is buried deep within the cell - Hyla versicolor has twice as many chromosomes as Hyla chrysocelis.  The other difference appears at night, when the frogs call; versicolor's call is a slow staccato trill, while chrysocelis' call is a fast staccato trill. 

A frog that spends much of the time up in trees and bushes over or near water, coming down at night for water and insects.  They can be common in areas without being seen much by humans.  The colors and patterns they show vary, but are usually a mimic of bark. The males show a yellow flash mark in the 'pit' of the hind leg (see top photo).  Down in southern Illinois,  the roads can be covered by calling males during the May rains.

Another underappreciated North American frog.

Hyla chrysocelis