Leptopelis yaldeni Largen, 1977  

A small (Males 26-34 mm, females 38-43 mm) semi-arboreal species from montanegrasslands in Ethiopia with a characteristic voice consisting of a clack preceded by one or more screams. Pattern either brown with indistinct darker blotches, often forming an interorbital bar and a triangular dorsal mark, or bright green. Males with well defined pectoral glands.It is notable that the frequency of the two colour phases varies, a feature otherwise unknown in the family. In the very open pasture land which predominates at altitudes at about 2700 m, almost all specimens belong to the greenphase. At about 2000 m where watercourses are frequently lined by thickets, only the brown phase has been found, while both phases occur in approximately equal numbers at about 2500 m. This may be because green specimens have a distinct selective advantage when living in close-cropped grass.
Voice. - The males call from exposed positions, either on the ground if there is no vegetation or from close-cropped grass. If taller herbaceous vegetation is available the males will often choose to call from elevated positions. An unusual feature among the genus is that large numbers of males can be found calling together, often only a few centimetres from each other. The voice is a series of screams followed by a click. The scream has a peculiar acoustic quality caused by a large number of harmonics about 300 cps. apart with an intensity maximum of these at about 1500-2500 cps. The scream has a longer duration that in the other "savanna screamers".

This account was taken from "Treefrogs of Africa" by Arne Schiøtz with kind permission from Edition Chimaira publishers, Frankfurt am Main.