INTRODUCTION'. 
THE AVES, OR BIRDS, 
Lay eggs from which their young are hatched by what is called 
incubation. Their skins are covered with feathers ; and their jaws 
are horny, without teeth. Their blood is warm, and circulates like 
that of the mammalia. The six orders of Aves are as follows : 
1. Raptores, or birds of prey. These birds are distinguished by a 
very strong and sharp bill more or less curved, but always 
hooked at the extremity of the upper mandible, which is co- 
vered at the base with a kind of skin called the cere. The 
nostrils are usually open. The legs are very strong, and 
generally only partially covered with feathers ; the feet are 
large, and the toes, which are four in number, are armed with 
very strong, sharp, curved, prehensile claws. The principal 
raptorial birds are the vultures, including the condor; the fal- 
con family, including the eagles, hawks, kites, and buzzards ; 
and the owls. 
2. Insessores, or perching birds. These birds have all feet formed 
for perching, the hind toe springing from the same place as 
the other toes, which gives them great power of grasping. Their 
legs are of moderate length, and their claws not sharply 
curved. This order includes the thrushes, nightingales, and 
all the finest songsters of our groves, with the robin-redbreast, 
the sparrow, and other birds seen about dwellings, the swal- 
lows, the larks, the crow family, the kingfishers, the birds of 
paradise, and the humming birds. 
3. Scansores, or climbers. These birds have two toes before and 
two behind, or rather they have the power of throwing one of 
the fore toes back at pleasure. This construction gives them 
such great power of climbing, that they can ascend the per- 
pendicular trunk of a tree. The principal birds in this order 
are the parrot family and the woodpeckers. 
4. Rasores, or gallinaceous birds. These birds have the head small 
in. proportion to the body. The bill is generally short, with 
the upper mandible somewhat curved, and furnished with a 
cere. The nostrils have usually a protecting fleshy membrane. 
The tarsus, or lower part of the leg is long and bare, and there 
are four toes, those in front being united by a slight mem- 
brane, while that behind is generally higher up the leg, and 
smaller than the others. This order comprises nearly all the 
birds used as food, and it includes the peacock, the turkey, the 
common cock and hen, the partridge, the pheasant, and the 
pigeon family. 
5. Grallatores, or "Waders. These birds are characterized by their 
long and slender legs, and generally bare thighs. Their feet 
have generally three toes, more or less united at the base by 
