INTRODUCTION. 
59 
many they are depended on as of much importance 
in the winter stock of food ; and among the inhabi- 
tants of the arctic countries, where they are migra- 
tory, the appearance of the first train of geese is 
looked for and watched with intense anxiety. — 
Guano, now bearing so much importance as a ma- 
nure, is the dung of birds belonging to this order. 
In proportional numbers, we have nearly one- 
third of the whole British birds Natatores. The 
Tertebrata of Mr. Jenyns, as a recent list (though 
later investigations have slightly added to it), will 
serve as a general guide. The total number of 
British birds enumerated by him, exclusive of 
twenty-six doubtful species, is three hundred and 
twelve, of which the Natatores furnish ninety, while 
the Incessores only muster one hundred and eight, 
a proportion which could occur in no district ex- 
cept one situate similarly with our own islands. 
Of tho Natatores, again, one-lialf nearly is made up 
of the Anatidm or ducks, there being, according to 
the above-mentioned list, forty-one species, including 
the Mergi or Gooseanders. The remainder is chiefly 
composed of the Laridce or gulls, including tho 
terns and petrels ; while the grebes, divers, cormo- 
rants, and solan-goose make up the remainder. 
