INTRODUCTION. xiii. 



course to the estuaries and to the sea, the ornithologist is 

 delighted with the view of the various clean-feathered inha- 

 bitants, feeding or preening themselves on the shores, swim- 

 ming or diving in the current, or wheeling aloft on the wing. 

 Many of these divide their time between the fresh and the 

 salt waters, and serve as aerial guides, to direct his sight over 

 the vast expanse, to other classes of birds that almost entirely 

 commit themselves to the ocean; and with those tribes at 

 certain seasons, these associate. This multifarious host, thus 

 assembled in distinct families, is sometimes seen to cover the 

 surface of the water to a vast extent : and of all these various 

 families, those of the Anas genus, which keep much at sea, 

 form the most considerable, amounting (according to Latham) 

 in the whole to ninety-eight species, besides varieties,* a 

 number exceeding that of any other kind. And when we 

 consider that each family of this genus is often seen in con- 

 siderable flocks, and add them to those which may more 

 properly be called sea-fowl we shall find the aggregate far 

 to exceed in number the whole of the birds that are supported 

 on the land. Whilst these fishers, in their flying squadrons, 

 are viewed from the cliffs and shores of the sea, soaring 

 aloft, or resting secure on the leuring precipice, the ear is 

 often pierced with their harsh shrill cries, screamed forth in 

 mingled discord with the roaring of the surge. Grating as 

 their cries are, these birds are often hailed by the mariner, 

 as his only pilots, while he is tossed to and fro, amidst soli- 

 tary rocks and isles, inhabited only by the sea-fowl. 



Although it is not certainly known to what places some of 

 these kinds retire to breed, yet it is ascertained that the 

 greater part of them hatch and rear their young on the rocky 

 promontories and inlets of the sea, and on the innumerable 

 little isles with which the extensive coast of Norway is stud- 



* It is very probable that many of these varieties, as well, perhaps, 

 as others that are accounted distinct species, may be a mixed breed, 

 the produce of a kind somewhat different; and that this may also be 

 the case with the varieties of other genera of birds. 



