MIGRATION AND SEX RECOGNITION IN FROGS 327 



but some winter elsewhere, perhaps in near-l^y bodies of water or 

 possibly in such favorable locations on land as in masses of dead 

 vegetation. In other locations than White's Wood the writer 

 has found leopard frogs hibernating under conditions fulfilling 

 all three of the above possibilities : in the mud of bodies of water 

 where later the species was commonly found breeding, in mud and 

 plant material in the bottoms of streams which were swift flow- 

 ing and unfavorable for breeding, and, lastly, in masses of swamp 

 grass in lowland. In White's Wood frogs might have wintered 

 in the pond, in adjoining ponds, in springs or a creek near the 

 observation pond, or in the adjacent wood and field. Wherever 

 they may have been for the winter, many frogs resorted to the 

 observation pond to breed. The questions of what incited a 

 spring migration of those frogs hibernating away from the pond 

 and of the conditions under which it occurred are of interest. 



But little benefit can be expected from direct observations, 

 because of the relatively small number of frogs that can be noted 

 in their migration. Banta ('14) mentions his observation of two 

 female wood frogs making their way to the pond where he 

 studied the mating behavior of this species. While at White's 

 Wood no effort was made to collect data by direct observation, 

 the following records were made. On March 27th, at 10:30 a.m., 

 a female leopard frog was found in the field adjoining the pond, 

 headed toward the water. In several instances ovaries and ovi- 

 ducts, presumably of the leopard frog, were found 90 to 100 

 feet distant from the pond. Possibly these remains represented 

 migrating frogs captured on their way by crows. Between 9 

 and 10 P.M. of March 31st, during a warm rain, dozens of spring 

 peepers were captured while they were rapidly hopping toward 

 the pond from its wooded side. Extended data on migration 

 were obtained from the trap catches, presented below in table 1. 

 Following the table are extracts from field notes which describe 

 weather conditions for three days preceding the beginning of 

 trap catches and during the period of maximum migration, in- 

 cluding also observations of frogs appearing within the pond. 



