SNTRODUCTIONi 
XI 
fearches by the brooks and the rivers, in their lengthened courfe 
to the eftuaries and to the fea, the ornithologift is delighted 
with the view of the various clean-feathered inhabitants, feeding 
or preening themfelves on the Ihores, fwimming or diving in the 
current, or wheeling aloft on the wing. Many of thefe divide 
their time between the frefti and the fait waters, and ferve as 
aerial guides, to diredl his light over the vail expanfe to other 
clalTes of birds that alnjoft entirely commit themfelves to the 
ocean ; and with whofe tribes, at certain feafons, thefe alTociate. 
This multifarious hoft, thus alTembled in diftindt families, is 
fometirnes feen to cover the furface of the water to a vail extent : 
and of all thefe various families, thofe of the Anas genus, which 
keep much at fea, form the moll conliderable, amounting in the 
whole to ninety-eight fpecies, belides varieties, a number ex- 
ceeding that of any other kind. And, when we conlider that 
each family of this genus is often feen in confiderable flocks, 
and add them to thofe which may more properly be called 
fea-fowl — beginning with the Alca^ and ending with the Pe^ 
licanm — conlifting of nine diftincl Britifii genera and their fpe- 
cies, we lhall find the aggregate far to exceed in number the 
, whole of the birds that are fupported on the land. Whilfl: thefe 
fifliers, in their flying fquadrons, are viewed from the cliffs and 
Ihores of the fea, foaring aloft, or refting fecure on the lowering 
precipice, the ear is often pierced with their harfli Ihrill cries, 
fcreamed forth in mingled difcord with the roaring of the furge. 
Grating as their cries are, thefe birds are often hailed by the 
mariner, as his only pilots, while he is tofled to and fro, amidfl: 
folitary rocks and ifles inhabited only by the fea-fowl. 
Although it is not certainly known to what places fame of 
thefe kinds retire to breed, yet it is afcertained that the greater 
* It is very probable that many of these varieties, as well perhaps 
as others that are accounted dIstincSl: 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. 
