Natural History of the Bird-voiced Treefrog (Hyla avivoca) and Green Treefrog (Hyla cinerea) in Southern Illinois

The bird-voiced tree frog,Hyla avivoca Viosca 1928 and green tree frog, Hyla cinerea(Schneider 1799) are distributed primarily on the Atlantic and Gulf coastal plains of the southeastern United States(Conant and Collins 1998).The ranges of both species reach their northern limits in the Midwest in southern Illinois where Smith (1961) recorded them from Alexander, Jackson, and Union counties. Because the few documented localities of these tree frogs in Illinois were, until recently, mainly in or near remnant Austroriparian swamplands(which are disappearing rapidly), concern has been expressed that their continued existence in the state is in jeopardy (Ackerman 1975; Ashton et al. 1976; Dyrkacz 1974). Since Smith's(1961)comprehensive study The Amphibians and Reptiles of Illinois, few additional records for these species have been reported. Carton and Brandon(1975)studied reproductive ecology andh abitat of H. cinerea at a southern Illinois swamp, but there has been no previous in depth environmental examination of H.avivoca in Illinois. The objective of this publication is to report the results of our study of the natural history of these two poorly known tree frogs in southern Illinois.