100 HABITS AND INSTINCTS OF ANIMALS. CHAP. IV. 



but for a short distance ; and the motion of the wings 

 is so rapid, as to be imperceptible to the closest ob- 

 server. Geese, and cranes, and most wild fowl, move 

 in figured flights, the flock being generally arranged in 

 a triangle ; but the individuals often change their po- 

 sition. In these, and most of the wading genera, as 

 the sandpipers, &c., the tertial quills are very long, and 

 the primaries pointed ; a structure which enables them 

 to cut through the air, probably, with greater facility. 

 Dabchicks, moor-hens, and coots, on the contrary, are 

 feeble-flighted birds, which merely skim the surface, 

 and fly with their legs hanging down. This originates 

 not only in the shortness of their wings, but in their 

 very forward position, by which they are placed as much 

 out of the true centre of gravity as are the legs of auks, 

 divers, and even of the coots themselves ; that is, they 

 are placed far behind the equilibrium of the body. 

 There is no imperfection, however, in these birds ; be- 

 cause their uncommon aptitude in diving amply com- 

 pensates for the slight development of their wings ; 

 and they so seldom venture beyond the margin of their 

 watery haunts, that they are rarely left without instant 

 means of escape from their enemies. 



(122.) The greatest powers of long-sustained flight, 

 however, are given to the natatorial and the fissirostral 

 types, or the oceanic birds and the swallows, but for 

 very different purposes. The food of the first is to be 

 sought for at a great distance from land ; their prey, 

 which consist entirely of marine or oceanic animals, 

 are constantly shifting their quarters ; and it is, there- 

 fore, necessary that their pursuers should be such per- 

 fect flyers, as to be continually on the wing, either fol- 

 lowing or seeking them. Added to these reasons for 

 the superior flight necessary to aquatic birds, it will be 

 remembered that they are exposed, on the unsheltered 

 bosom of the ocean, to far more violent storms than are 

 encountered by their brethren on the land : hence, were 

 they not endowed with far more muscular strength of 

 wing, they would inevitably perish, either by being 



