During the spring and summer this year I was conducting frog call surveys as a part of my graduate research. I found this little juvenile gray tree frog at a mitigation wetland in Whiteside County around 11:00 pm at the end of July. Gray treefrogs have a very distinct call, check it out here. There are actually two species of gray treefrogs in Illinois- the eastern gray treefrog (Hyla versicolor) and Cope’s gray treefrog. However, they are morphologically identical, and can be very difficult to distinguish in the field. Read more about the two species here.