GRAY TREEFROG (two almost indistinguishable species -generally IDd by voice)

Hyla versicolor (Gray Treefrog) sometimes called Eastern Gray Treefrog
Hyla chrysoscelis (Cope's Gray Treefrog) sometimes called Southern Gray Treefrog
these two can only be told apart by voice and geographical range (and those are iffy for obvious reasons)

http://www.paherps.com/herps/frogs-toads/gray_treefrog/
http://www.nhptv.org/natureworks/graytreefrog.htm
http://www.fieldherpforum.com/forum/viewtopic.php?f=2&t=5536
-they share much of their geographic range
-both sp. variable in color, mottled gray to gray-green
-can change color but slower to change than chameleon, can turn pattern on and off too
-woodland habitats, will sometimes travel into more open areas to reach a breeding pond
-Cope's has a faster-paced and slightly higher-pitched call than H. versicolor
-H. chrysoscelis reported to be slightly smaller, more arboreal, and more tolerant of dry conditions than H. versicolor

example of Cope's showing same orange/yellow patches on thighs:
http://srelherp.uga.edu/anurans/hylchr.htm