2030 AVES. 
which is only assumed in their third or fourth year, a circumstance 
which has occasioned a great multiplication of species. The female 
is generally one-third larger than the male, which, on this account, 
is styled a tarsel, or tercel. We should, first of all, subdivide this 
genus into two great sections. 
NOBLE BIRDS OF PREY. 
Fatco, Bechst. Fatcons, properly so called. 
The true Falcons constitute the first, and, in proportion to their 
size, are the most courageous, a quality which is derived from the 
power of their arms and wings; their beak, curved from its base, 
has a sharp tooth on each side of its point, and the second quill of 
their wings is the longest, the first nearly equalling it, which ren- 
ders the whole wing longer and more pointed. From this, also, 
result peculiar habits: the length of the quills of their wings dimin- 
ishes their vertical power, and compels them, in a calm state of the 
atmosphere, to fly obliquely forwards, so that when they wish to 
rise directly upwards, they are obliged to fly against the wind. 
These birds are the most docile of all those employed by falconers, 
who teach them to pursue game, and to return at their call. Their 
wings are longer than their tails. 
F. communis, Gm.(1) (The Common Falcon.) As large as 
a hen, and distinguished by a triangular, black moustache on 
the cheek, larger than that of any other species of the genus $ 
it varies as to colours nearly in the following manner : when 
young, it is brown above, the feathers edged with reddish ; un- 
derneath whitish, with longitudinal brown spots. As it increases. 
in age, the spots on the belly andthighs have a tendency to form 
transverse blackish lines, and the white increases on the throat 
and root of the neck; the plumage on the back, at the same 
time, becomes more uniform, and is of a brown, transversely 
striped with a blackish ash colour ; the tail is brown above, 
with pairs of reddish spots, and beneath with pale bands which 
diminish in width with age; the throat is always white; the 
feet and the cera of the beak are sometimes blue and sometimes 
yellow. These variations may be followed, Enl. 470, the young ; 
(1) We must take especial care not to refer to this species the pretended varie- 
ties of the Fulco communis given by Gmelin. Thus the var. «, Frisch. 74, is a Buz- 
zard ; d, Id. 75, is a Booted Buzzard; ¢, Id. 80, the Falco pygargus, L.; 6, Id. 76, 
a Buzzard somewhat paler than usual ; x, Aldrov. 494, a very distinct species, &c. 
On the contrary, the F. islandicus, barbarus and peregrinus may all be the Common 
Falcon at different periods of moulting. 
