130 ECOLOGY AND LIFE HISTORY OF THE COMMON FROG 



surely cover anytliing likely to happen in these islands. It is, of course, 

 probable that if a period of exceptionally severe weather set in so that 

 the ponds froze again, spawning would be prevented, but this is not 

 what is usually meant when it is suggested that the animals are con- 

 trolled by temperature. 



Rainfall 



The London charts show clearly that rainfall at the spawn season is 

 not necessary. In 1929, spawning began in dry weather, and continued 



RAIN 



.,^v 



^^: 



:a^Z: 



-H' 



d 



- I I I l i 



J Leal I 



MARCH 9 APRIL I MARCHI9 FEB 23 



Fig. 33. The Relation of Rainfall and Temperature to Spawning 



in the Two Places where Observers Lived in the Village or Town in 



which One of the Five First Order Observatories was situated 



At these observatories, houriy records of weather are kept, (a) Eskdalemuir 

 1930, (b) Eskdalemuir 193 1, (c) Eskdalemuir 1932, (d) Valentia 1932. There 

 is not the shghtest doubt that the weather of these places was as stated. 

 These charts show the very different weather in which frogs spawn. Note 

 particularly that in Eskdalemuir in 193 1 there was a frost every night of the 

 previous week, and a falling temperature in this period. In Eskdalemuir in 

 1932 and at Valentia in the same year, there was hardly any rain. 



during a period that became a drought, relieved by two small showers 

 late in March. The April rain brought no peak of spawning, for most 

 of the frogs had by then laid their eggs. The wet period at the end of 

 February 1927 did not produce a peak in the spawning. At Eskdale- 

 muir in 1930, there was heavy rain in the later part of the night and 

 the next day after a wet week, but in 193 1 no rain fell on the night of 



