ACCIPITRES. 163 
again excepted] pursue other Birds ; their flight accordingly is mostly powerful. The 
greater number still retain a slight web betwixt their external toes. 
The Passerine Birds comprise many more species than all the other families ; but 
their organization presents so many analogies that they cannot be separated, although 
they vary very much in size and strength. Their two external toes are joined at the 
base, and sometimes higher. 
Finally, the name of Climbers is applied to those Birds in which the external toe is 
directed backwards like the thumb, because the greater number of them [some of them] 
avail themselves of a conformation so favourable for a vertical position, to climb along 
the trunks of trees.* [As constituted upon this single character, the present group is 
a most unnatural one, excluding genera that in every other respect belong to it, and 
including the Parrots, which differ widely from the rest in every other detail of their 
conformation. Besides the Parrots, also, which are the only true climbers among 
Birds, (if we except perhaps the Colies,) the Woodpecker and Barbet groups comprise 
all the yoke-footed species which ascend the trunks of trees, the latter only being 
enabled to descend them ; and corresponding genera to these occur among the Passerine 
Birds, as the Creepers and their allies — to the Woodpeckers, and the Nuthatches — to 
the Barbets. The Trogons moreover, as stated at p. 156, are yoke-footed on a different 
principle from the rest. We have no hesitation in placing the Parrots at the head of 
the whole series of the class of Birds.] 
Each of these orders subdivides into families and genera, principally after the con- 
formation of the beak. But these different groups pass into each other by almost 
imperceptible gradations, insomuch that there is no other class in which the genera 
and subgenera are so difficult of limitation. 
THE FIRST ORDER OF BIRDS,— 
THE BIRDS OF PREY {ACCIPITRES, Lin.)— 
Are recognized by their hooked beak and talons, — powerful weapons, with which they immo- 
late other Birds, and even the weaker Quadrupeds and Reptiles. They are among Birds what 
the Carnivora are among Quadrupeds.f The muscles of their thighs and legs indicate the 
force of their claws ; their tarsi are rarely elongated : they having all four toes ; and the claw 
of the thumb and that of the innermost toe are the strongest. 
They constitute two families, the Diurnal and the Nocturnal. 
The Diurnal Birds of Prey have the eyes directed sideways; a membrane, termed the 
cere [as in the Parrots], covering the base of the beak, in which the nostrils are pierced ; three 
toes before [the outer in the Osprey genus reversible], and one behind, unfeathered, the two 
exterior almost always connected at base by a short membrane ; the plumage close, the quills 
strong, and flight powerful. [They have constantly a large craw (fig. 71) or dilatation of the 
gullet] ; their stomach is almost wholly membranous ; their intestines [save in the Osprey 
genus] but little extended, and furnished with minute coeca. The sternum (fig. 72) is large 
and completely ossified, [or with only a posterior foramen left, in most of the genera], in 
order to give more extended attachment to the muscles of the wing ; and their fourchette 
* In my first Elementary Sketch, in 1798, I was oblig-ed to suppress I of recent Ornithologists, have assented to this suppression, 
the order Piets of Linnseus, which has no one determinate character, f As the frugivorous Parrots may be compared to the Quadrutnana. 
[at least as constituted by that naturalist]. M. Illiger, and the majority I — Ed. 
M 2 
