WILD LIFE IN SEVERN ESTUARY 23 



stands in an attitude of rapt attention. It is the 

 heron watching for its prey in the water, the most 

 beautiful bird of Western Europe. 



Save for the difference in length of the body, it 

 might be the great blue heron of the United States, 

 so similar is the appearance. It is the same general 

 look of the plumage, the same stoop of the shoulders, 

 the same trick of attitude, the same poise of the 

 same bayonet-shaped bill. We marvel at the varia- 

 bility of life. Yet it is surpassed by the still more 

 astonishing conservatism. One is startled when 

 meeting the second of two brothers who have lived 

 in different countries, and who have themselves 

 never met, to find that they have developed each 

 the same mannerism of stroking the side of the 

 nose in the midst of an argument. But these little 

 identical tricks and mannerisms of biological rela- 

 tives who have never met and who have been 

 separated in their careers by vast intervals of 

 geographical space and geological time, are more 

 startling. They serve to reveal to us as by a flash 

 not only the profound complexity, but the almost 

 incredible stability of the matter which constitutes 

 the physical basis of life. 



As we travel inland on foot the scene changes. 

 The surface of rich land formed from mud covered 

 by the sea at a previous time gives place to a layer 

 of peat marking the site of the swamp and lake of 

 ancient days. Many parts are still covered with 

 water and are overgrown with deep sedge. In 

 other parts the heather has nearly extinguished the 

 rival vegetation, while in others still the rich 

 meadows march with the wilderness. This land is 

 the retreat of vast numbers of water-fowl in winter 



