XVlii. INTRODUCTION. 



the united efforts of both are necessary in forming their 

 temporary habitations, and in rearing and maintaining their 

 offspring. Eagles and other birds of prey continue their 

 attachment for a much longer time, and sometimes for life. 

 The nests of birds are constructed with such exquisite art, as 

 to exceed the utmost exertion of human ingenuity to imitate 

 them. Their mode of building, the materials they make use 

 of, as well as the situations they select, are as various as the 

 different kinds of birds, and are all admirably adapted to 

 their several wants and necessities. Birds of the same spe- 

 cies, whatever region of the globe they inhabit, collect the 

 same kind of materials, arrange them in the same manner, 

 and make choice of similar situations for fixing the places of 

 their temporary abodes. To describe minutely the different 

 kinds of nests, the various substances of which they are com- 

 posed, and the judicious choice of situations, would swell 

 this part of our work much beyond its due bounds. Every 

 part of the world furnishes materials for the serial architects : 

 leaves and small twigs, roots and dried grass, mixed with 

 clay, serve for the external; whilst moss, wool, fine hair, and 

 the softest animal and vegetable downs, form the warm in- 

 ternal part of these commodious dwellings. The following 

 beautiful lines from Thomson are highly descriptive of the 

 busy scene which takes place during the time of nidifica- 

 tion : 



" Some to the holly hedge, 



" Nestling, repair, and to the thicket some; 



" Some to the rude protection of the thorn 



" Commit their feeble offspring: the cleft tree 



" Offers its kind concealment to a few, 



" Their food its insects, and its moss their nests : 



" Others, apart, far in the grassy dale 



"Or roughening waste, their humble texture weave: 



" But most in woodland solitudes delight, 



" In unfrequented glooms or shaggy banks, 



" Steep, and divided by a babbling brook, 



" Whose murmurs soothe them all the live-long day, 



