412 HAWK 
value, but in other respects quite as important, that the sexes differ 
very greatly in size, that in most species the irides are yellow, 
deepening with age into orange or even red, and that the im- 
mature plumage is almost invariably more or less striped or 
mottled with heart-shaped spots beneath, while that of the adults 
is generally much barred, though the old males have in many 
instances the breast and belly quite free from markings. Nearly 
all are of small or moderate size—the largest among them being 
the Gos-Hawk and its immediate allies, and the male of the 
smallest, Accipiter tinus, is not bigger than a Song-THRusH. They 
are all birds of great boldness in attacking a quarry, but if foiled 
in the first attempt they are apt to leave the pursuit. Thoroughly 
arboreal in their habits, they seek their prey, chiefly consisting of 
birds (though reptiles and small mammals are also taken), among 
trees or bushes, patiently waiting for an unwary victim to shew 
itself, and, when it appears, gliding upon it with a rapid swoop, 
clutching it in their talons, and bearing it away to eat it in some 
convenient spot. 
It is impossible to enter into details of the numerous forms 
which, notwithstanding the limitation above adopted, are to be 
called Hawks, or to describe the distinguishing characters, so far 
as any have been given, of the different groups or sections into 
which it has pleased systematic ornithologists to break them up, 
since hardly any two are agreed in the latter respect. There 
is at the outset a difference of opinion as to the scientific name 
which the most numerous and best known of these sections should 
bear—some authors terming it Nisus, and others, who seem to 
have the most justice on their side, Accipiter, 
In a wider sense the word, Hawk, includes a considerable 
number of forms which cannot be positively assigned to any of the 
groups already named, one instance of which, 
out of several that could be cited, is seen in 
the Neotropical genus Harpagus, whose deeply 
and doubly-notched bill! has caused it to be 
often put in the subfamily Falconine. But there 
its short and rounded wings, and the style of 
its successive plumages make it strangely out 
of place, so that its true position must be regarded as undetermined. 
The same characters, added to that afforded by its “amber” irides 
(Proc. Zool. Soc. 1882, p. 623), indicates that the rare form which 
had the misfortune to be named Spiziapteryx (Ibis, 1862, pl. i.) is 
a near ally of Harpagus, notwithstanding all that has been said to 
the contrary. One species of Harpugus is subject to MIMICRY. 
HARPAGUS. 
(After Swainson.) 
1 The ‘‘denticulations” are not merely superficial, as is the case with many 
birds possessing them, but exist, as Mr. Ridgway has shewn (Bull. U. S. Geol. 
and Geogr. Survey, ser. 2, no. 4, pl. xii. fig. 8), in the bone of the premaxilla. 
