16 
VERTEBRATA. 
Amongst their distinctive features tlie most important are those furnished by the bill and 
feet. The former of these organs is always rather short and strong, with the upper mandible 
longer than the lower one, strongly hooked at the tip, or curved throughout its whole length, 
very sharp at the point, and sometimes armed with teeth on the margins. The base of the bill 
is covered by a cere, in which the nostrils are pierced. The feet are usually short and powerful, 
composed of four toes, armed with long, curved, and acute claws. With the latter these birds 
seize their prey in a deadly grasp, and with them they hold the victim whilst the powerful 
bill is engaged in tearing off portions of its flesh. At the same time, the wings are always of 
large size, and often of extraordinary length, giving the birds an astonishing rapidity of flight. 
The tail is long and broad, usually composed of twelve feathers ; it is sometimes rounded and 
sometimes forked at the end. 
The tarsi are rarely famished with scutella as in the Passerine birds, but, like the toes, they 
are generally covered with a reticulated skin, although in some cases a few scutella are found 
upon the front of the tarsi and the upper part of the toes. The latter are arranged three in front 
and one behind, and the anterior toes are usually united at the base by a short membrane, except 
in the owls, in which the outer toe is capable of being turned backward and the inner one alone 
is united to the middle toe by a membrane. In some instances the feet are feathered down to the 
toes. The raptorial birds are very generally distributed over the globe. They vary greatly in 
size, but the majority feed upon the flesh of animals which they capture for themselves ; some of 
the smaller species, however, condescend to prey upon insects. They are divided into three ex- 
tensive families, the Falcons^ the Vultures^ and the Owls. 
THE FALCOmDJE. 
In this family, which not only includes Falcons proper, but Hawks and Fagles, the destruct- 
ive power is most perfectly developed; and we 
find in the birds composing it natural instruments 
for striking, trussing, and dissecting their prey, 
combined with a power of flight and strength of 
hmbs equivalent to the necessities of the case, 
whether the prey be aerial — that is, in the act of 
flight — or on the ground. These natural weapons 
are rendered still more formidable by the organiza- 
tion of the whole animal, which is calculated to 
give them the greatest possible etfect. The nails, 
or claws, to be available, must be sharp ; and, in 
order that they may be kept in this state and fit 
for duty, there is a provision to enable the bird to 
prevent them from coming in contact with the 
ground or other foreign hard bodies ; for the claws 
are retractile, not indeed in the same manner as 
those of the cats, which have the power of with- 
drawing or sheathing theirs within the integu- 
ments, but by a conformation which gives the bird 
of prey the power of elevating its claws at pleas- 
ure. The claws of falcons when sitting on stones 
or large branches of trees have often a cramped 
appearance ; but this arises in most instances from 
the care of the bird so to arrange its talons that 
their points may not be blunted against the perch. 
It is one of the remarkable characteristics of this 
family, in common with other Raptores, that the females are considerably larger than the males. 
All the Falconidae have wings df large size, and are remarkably powerful fliers. They pursue 
HEAD AND FOOT OF PEEEGEINE FALCON. 
