ON THE MIGRATION OF BIRDS. 
to perform the functions of incubation and nu- 
trition in full security. They and their young 
quit their retreat in September, and disperse 
themselves over Europe. With us they make 
their appearance the beginning of October ; cir- 
culate first round our shores, and when com- 
pelled by severe frost, betake themselves to our 
lakes and rivers. Of the web-footed fowl there 
are some of hardier constitutions than others; 
these endure the ordinary winters of the more 
northern countries, but when the cold reigns 
there with more than common rigor, repair for 
shelter to these kingdoms: this regulates the 
appearance of some of the Diver kind, as also 
_ of the wild Swans, the long-tailed Duck, and 
the different sorts of Goosanders which then 
visit our coasts. 
The Corvorant and Shag breed on most of 
our high rocks: the Gannet in some of the 
Scotch isles, and on the coast of Kerry: the 
the Dutch discovered them on the rocks of that country and in 
Waygate Straits. ‘They, as well as the other species of wild 
Geese, go very far north to breed, as appears from the histories of 
Greenland and Spitzbergen, by Egede and Crantz. These birds 
seem to make Iceland a resting place, as Horrebow observes, 
few continue there to breed, but only visit that island in the 
spring, and after a short stay, retire still further north. 
The Swallow tailed Shield Duck breeds in the Icy Sea, and is 
forced southward only in the very hard winters: Amen. Acad. 
IV. 585. . 
393 
Corvo- 
RANTS. 
