FROGS 



3 4 5 6 



TEMPERATURE C 



SE 

 WIND D 



Fig. 27. Net Regression Curves of Migration on Rainfall, 

 Temperature and Wind Direction 



No high accuracy is claimed for these curves, but they probably represent 

 the facts reasonably well. The minimum in the wind direction curve is due 

 to the removal of the temperature and rainfall effects. Winds in this 

 quarter are commonly wet and warm, and some of the migration was 

 apparently due to these factors. Note that the removal of the other factors 

 has not altered the predominance of the southerly migration, but has merely 

 shifted the maximum shghtly to the east. It seems impossible to ascribe 

 migration over the road to rain or high temperature. 



109 



