The Peeper, Hyla pickeringii (Holbrook). 



37 



middle of May the ear-splitting concert begins to abate, and by June 1 

 very few are to be heard; seldom after June 15 do we hear the peeper. 



The question naturally arises, do not temperatures of water rather 

 than of air influence the time of chorus? At this period the males are 

 either on the bank or at the water's surface in either case, more or 

 less exposed to the air. Moreover, the peeper is more frequently found 

 in shallow water, where, after the ice has gone the water quickly 

 responds to air-temperatures. A consideration of 24 simultaneous 

 air- and surface-temperatures, taken in chorus-season in years 1908 to 

 1911, shows that an average of the air-temperatures is 64 degrees, while 

 the average of the surface-temperatures is only 3 degrees lower. In no 

 case, with two exceptions, was a chorus recorded where the water surface 

 descended below 57 degrees. 



THE MATING. 



We believe that the males are the first to appear in the ponds, 

 though the retiring females may arrive at the same time. We consider 

 that the males migrate day and night until arrival, more actively at 

 night. Two of our ponds are situated at the bases of wooded embank- 

 ments, 75 to 100 feet high, with eastern and southeastern exposures. 

 Along these, from top to base, in early spring, we discover males migrat- 

 ing by day to the ponds. Or near other ponds rarely by day, more 

 often by night, we occasionally capture the males on their way through 

 the grass to the ponds. Never by day or at night, with the flash-light, 

 have we so taken females. Rarely we do capture on the above em- 

 bankments, in daytime, female peepers hiding under stones, some near 

 the ponds, others at different distances up the embankment all of 

 which seems to indicate that the females are not so eager to hasten 

 their migration or to enter the ponds until ready for ovulation. Our 

 latest dates for males migrating downward from the crests of the embank- 

 ments are April 18, 1910, and April 18, 1911, by which time most of the 

 males have already arrived at their breeding-places. Once with the 

 concourse, life is very strenuous and active for the males. They are 



