AVES. 309 
spot. It builds its nest usually on the ground, and breeds throughout the 
United States. 
Several South American species are known, though their history has 
never been investigated; they are C. palustris, C. histrionicus, which is a 
bird remarkable for its gaily striped plumage, and others. 
The only hawk which possesses a musical voice, the singing hawk of the 
old authors’ (Melierax musicus), belongs to this sub-family. It is a 
common bird in Southern Africa, and is described by Le Vaillant as 
capable of performing quite respectably a considerable variety of notes. It 
appears to be a timid species, living upon reptiles, and partaking of the 
general habits of its family. 
Here also has been classed a curious African genus, Polyboroides, the 
species of which have entirely bare faces, and necks also bare to some 
extent. They appear, however, to be more nearly related to the Poly- 
borine, or to the vultures. Little is known about them beyond the mere 
fact of their existence in Western and Southern Africa, and future investi- 
zations must decide their claims to classification. 
The extraordinary and apparently anomalous genus Serpentarius has 
also been assigned by late ornithologists to this sub-family. The only 
species is the secretary, or great serpent-eater, of the plains of Southern 
Africa, which, with a decidedly aquiline head and beak, has the long legs 
of a crane, and lengthened crest and tail. It lives almost exclusively upon 
the Jarger snakes, the most poisonous species of which it is said to seize 
with much dexterity and despatch with great quickness, regardless of their 
bites upon its Jong and well shielded tarsi. Spending its time in search of 
serpents, this powerful bird constantly walks upon the ground, presenting 
more the appearance of a crane, or large heron, than a bird of prey. It is 
a shy and very cautious bird, and is regarded by the colonists as very 
useful in destroying serpents, which it pursues on foot. The stomach of a 
specimen examined by the celebrated Le Vaillant contained no less than 
three snakes, eleven lizards, and portions of others. 
With this sub-family we conclude the Falconide, and now proceed to 
the last family of rapacious birds. 
Fam. II. Srricma, or Owrs. Head usually very large; eyes large, 
directed forwards, and surrounded by a circle more or less complete of 
slender hair-like feathers, forming a facial disk. Bill short, generally 
strong, and partially concealed by projecting bristles, curved and much 
hooked. Wings usually strong. Tarsi short, and usually thickly clothed 
with short feathers, but sometimes naked or partially covered; claws long 
and acute. Plumage soft, habits almost exclusively nocturnal. 
This family embraces the nocturnal birds of prey, all of which are 
familiarly known under the general cognomen of owls. They differ in 
many respects from the birds of the two preceding families, but yield to 
them in nothing of the ferocity or destructiveness characteristic of this 
class. The most striking and peculiar external character of the owls is 
the position of their large and staring eyes, which enables them to look 
directly forwards, and is not the case in any other birds. Their soft and 
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