BIRDS. 227 



ing their nests, the period of incubation, and the condition 

 of the young brood. These diiferences never fail to arrest 

 the attention of the practical naturaUst, and their contem- 

 plation is well calculated to instruct and amuse *. 



The characters by which birds are separated fi'om other 

 animals, are so obvious, as to be easily detected even by 

 an inexperienced observer. It is extremely difficult, how- 

 ever, to distribute them into subordinate groups. All the 

 species have so many points of resemblance, by ])ossessing 

 the same organs, that characters can only be obtained from 

 the modification of these. Even when the modifications of 

 any one character are employed, we find so many transi- 

 tions from one kind of development of an organ to an- 

 other, as to render it impracticable to draw a definite line 

 of separation. If we employ the common divisions of land 

 and water birds, we shall find that there is an extensive 

 group called Grallae or Waders, which hold an intermediate 

 rank. They frequent marshy ground, and the margins of 

 rivulets. Some of the species of this group, bear a very 

 close resemblance to the land birds in their habits. Tims, 

 the water-rail is intimately connected with the gallinule and 

 coot, as waders, on the one hand ; while, on the other, it 



* HrNTER conjectures, that some birds can remove their eggs from the 

 nest when they discover danger, at least, he has reason to suspect this of the 

 sparrow. (Phil. Trans. 1792, p. 30.) I have credible testimony, that 

 the partridge can remove its eggs to a safe place, carrying them under its 

 wing. The opinion that some birds will lay more than their ordinary num- 

 ber of eggs, by daily abstracting one from the nest, though countenanced by 

 Pennakt (Brit. Zool. i. p. 400.), on the authority of Lister, has never been 

 established by receat observations. Montagu, indeed, repeated Lister's 

 experiment on the swallow without success, (Ornith. Diet. i. p. xi.) nor 

 have we been more fortunate with the magpie, sparrow, wren, and chaf- 

 finch. 



p 9. 



