HABITAT AND MIGRATION. 47 



in species, at least in numbers ; and many young birds we can- 

 not succeed in rearing, or do it very partially, by reason of our 

 ignorance of the requisite food. Every one, who has made the 

 attempt, well knows the various expedients he has resorted to 

 of boiled meats, bruised seeds, hard eggs, boiled rice, and twenty 

 other substances, that nature never presents in order to find a 

 diet that will nourish them ; but Mr. MONTAGUE'S failure in 

 being able to raise the young of the Girl Bunting, (Linncean 

 Trans, vol. vii.) until he discovered that they required grasshop- 

 pers, is a sufficient instance of the manifest necessity there is for 

 a peculiar food in one period of the life of birds ; and renders 

 it probable that, to obtain a certain aliment, the Willow Wren 

 and others of the insect and fruit-feeding birds, direct their 

 flight to distant regions, and is the ' principal cause of their mi- 

 gration. 



"It is some stimulus like this which urges that little creature, 

 the Golden-crested Wren, that usually only flits from tree to tree, 

 and never attempts upon common occasions a longer flight, to tra- 

 verse the distance from the Orkneys to the Shetland Isles, over 

 stormy seas that admit of no possible rest during its long pas- 

 sage of about fifty miles ! there it breeds its young ; but this 

 one object accomplished, it leaves those isles, dares again its 

 tedious flight, and seeks a milder clime. With us it never mi- 

 grates, lives much in our fir groves during the winter, and breeds 

 in our shrubberies in summer. 



" Peculiar necessities, such as these, may incite the migration 

 of many birds ; but that certain species, which lead solitary 

 lives, or associate only in very small parties, should at stated 

 periods congregate from all parts to one spot, and there hold a 

 council an a removal, in which the very sexes occasionally sepa- 

 rate, is one of the most extraordinary procedures that we meet 

 with among animals." Extraordinary indeed ! may we not, in 

 this, as in all the phenomena which we behold in the world of 

 animated nature, trace the superintendence of an all-wise and 

 benevolent Creator, by whose direction it is that " the Stork in 

 the heavens knoweth her appointed time ; and the Turtle, the 

 Crane, and the Swallow, observe the period of their coming." 



