Lake Maxinkuckee, Physical and Biological Survey 635 



of the arrival of spring, the Swamp Tree-frog begins its chorus, 

 and although it is not the first frog to be heard, it is its chorus 

 coming from the woodland ponds and from the creeks and marshes, 

 that announces to the world in general that "the frost is out of the 

 ground." These frogs all seem to wake up at about the same 

 time, so that the very first song is a pretty full chorus. They 

 begin singing first in the pools and ponds surrounding the lake, 

 and only later stray down to the lake shore. In 1901 they were 

 first heard about March 23; at the beginning of their song season 

 they sang only during the warmer parts of bright days. Inter- 

 mixed with the chorus came at intervals the high piping of H. 

 crucifer. 



From March 23 to about the middle of April they sang chiefly 

 during the warmer part of the day, the chill of the night quickly 

 silencing them. About April 24 till May 9, they sang chiefly dur- 

 ing the evenings and mornings ; later on they sang in diminishing 

 numbers and chiefly on moist muggy nights. They were heard 

 singing as late as June 22. The song is a rattle with a rising in- 

 flection at the end, or like the scraping of a coarse-toothed comb. 



It was quite difficult at first to catch this frog in the act of 

 singing, as they become immediately silent on one's near approach. 

 On April 5 some were seen singing near Hawk's pond. The frogs 

 stuck their heads above the water, expanded the skin under their 

 throat until it looked like a large yellow bubble ; this vibrated some- 

 what, but did not collapse while the frogs were singing. All the 

 frog out of the water was pretty well hidden behind the bubble, so 

 that the animal itself easily escaped detection. Later on they were 

 occasionally seen singing in a row at the edge of the pools. A pair 

 were seen mating April 9 over by Hawk's pond. In a pond where 

 many were heard singing a number of small bunches of eggs were 

 found which probably belonged to this species. They were placed 

 in an artificial pool and kept under observation, but did not hatch. 



The small tadpoles soon develop, and about June minute frogs 

 of this species can be seen hopping about, leaving the water. 



The Swamp Tree-frog has a second season of song in autumn. 

 This is usually sung by individuals rather than in chorus, and the 

 singers are frequently found some distance from the water, any- 

 where in damp situations. They are quite frequently heard in low 

 copses or in cornfields on damp days in autumn, and one was known 

 to have its abode in a damp cellar a good distance from any pond. 

 One example found in autumn in a cornfield was quite plump, and 

 was found to be full of well developed eggs. As these frogs are 

 dormant during the winter it is probable that the ova reach their 



