THE RAIL. 245 



natures and habits in themselves, some pass over a greater 

 range and some over a less. The corn-crake reaches to the 

 northern isles, the spotted crake (with us at least) probably 

 not farther than England, and the smaller species only per- 

 haps to the south of that part of the island, and few in 

 number even there. The more discursive migrant has, as we 

 may suppose, the greatest aptitude to vary its food, just as 

 the resident bird, which with us passes one part of the year 

 in the shade of the forest or on the upland waste, and the 

 other in the fields by the farm-house or on the shore of the 

 sea, can have a more extensive range in its food than another 

 bird of the same genus which resides permanently in one 

 place. In corroboration of this, it may be mentioned that 

 Dr. Fleming, who resided in the northern isles, and who 

 must, as a professed and systematic naturalist, be presumed 

 to have made dissections there, describes the corn-crake as a 

 gizzard bird, (" its muscular gizzard intimates its gramini- 

 vorous habits," British Animals, p. 99,) while in England it is 

 considered a trail bird, and as such feeding chiefly upon 

 animal matter. The warblers also which range farther to the 

 north, feed more upon vegetable matters than those that 

 confine themselves to the south ; and there is no doubt that 

 the crakes follow the same gradations. 



The argument must not, however, be misunderstood ; for 

 there is a double in it : the inducement to migrate at all, 

 and the inducement to migrate far, are so far from being 

 associated, that they are each strongest in a different cha- 

 racter of bird. The nightingale, for instance, which ap- 

 pears capable of feeding upon insects and caterpillars of the 

 broad-leafed groves only, must be sooner compelled to mi- 

 grate from any locality than the white-throat, which is not 

 only more miscellaneous in its insect food, but can also sub- 

 sist upon berries. But the limitation of its food limits the 

 migratory range of the nightingale within far narrower 



