124 ECOLOGY AND LIFE HISTORY OF THE COMMON FROG 



in the rest of the inquiry, which must to some extent be anticipated. 

 The dominant weather factor is rainfall. The British Isles is usually 

 under the influence of weather systems coming from the Atlantic 

 Ocean, with the result that places in the west of the country, especially 



6W 5W 4W 3W 



SON 



Fig. 28. Map Showing the Relation of the Date of Spawning 

 to the Geographical Position 



where hills provide orographical effects, are the wettest. These places 

 can be picked out on the map, using only the frogs as a guide. Dart- 

 moor, Exmoor, the coastal strip backed by the hills of South Wales, 

 and the coastal areas of the West, are all represented. The Dorset 

 heights, the Yorksliire Hills and even the small patch backed by the 

 Cheviots, which interrupts the winds from the North Sea, all appear 



