xii INTRODUCTION. 



nests of the Icteridce. Professor Newton shows, by 

 several instances, " how the dictates of hereditary 

 instinct are by a remarkable degree of elasticity, in 

 some species, rudely broken." If I recollect right, 

 he was present with me in the examination of a 

 Heron's nest built on the united summits of a reed- 

 bed, more than three or four feet from the surface 

 of the surrounding water, on which floated the body 

 of the unfortunate chick, which would not, in all 

 probability, have come to so untimely an end, had 

 the parents chosen the usual lofty and safer site for 

 their nest than the reed-bed. (See p. 129.) 



The annual moult to which birds are subject is 

 an important provision for their preservation, and the 

 means for restoring the injuries sustained between 

 the periods of moulting. The wing and quill feathers 

 especially are liable to be broken or split, so as to 

 deprive the bird of power of flight, or at all events 

 to impede its aerial progress. With the exception of 

 the AnatiddB and Spheniscidce, which shed their quill 

 feathers simultaneously, and remain in a defenceless 

 condition, hidden among sedge and grass, or keeping 

 to the water until they have reassumed their full 

 plumage, all other birds moult their feathers in pairs, 

 by which an equilibrium is maintained, their flying 

 powers remaining unimpaired. 



Dorsetshire has a large and varied avifauna, owing 

 mainly to its extensive seaboard and being in the 

 migratory line of several birds. The coast includes 

 the cliffs of St. Alban's, Gadcliff, Whitenore, Old 

 Harry, and Durlston ; the sandbanks of Small- 



