520 SYSTEMATIC SYNOPSIS. —BAPTOBES— AC CIPITRES. 
falcons; 5. Polyhorince, caracaras; 6. Buteonince, buzzards and eagles. If it be urged that 
these groups grade into one another, it may be replied that most large groups of like grade in 
ornithology do the same ; and that ' typical ' or central genera of each of them offer practical 
distinctions which have been recognized from time out of mind, in popular opinion and ver-" 
nacular language. Tn my recent revision of the North American Falconidce, made to check 
and amplify the descriptions in this work, an interesting relation between the shape of the 
wings and their pattern of coloration presented itself, (a) If we take a ' noble ' falcon, such as a 
peregrine or a lanner, we find a strong, yet sharp wing, with the second primary longest, sup- 
ported nearly to the end by the first and third ; the nicking of the quills confined to a few, if 
occurring on more than one, and situated near the tip. Such a wing is as potent in its feathers 
as in the construction of its shoulder-joint, and indicates the acme of raptorial power in its pos- 
sessor, a falcon being able to dash down upon its quarry with almost incredible velocity and 
violence. The markings of a falcon's wing are no less characteristic, consisting of clean-cut, dis- 
tinct spots of light color on both webs of the primaries and secondaries, throughout their wiiole 
extent, or almost so. (b) Any true ' hawk,' as an Astur or Accipiter, has a rounded concavo- 
convex wing, conferring a rapid, almost whirring, flight, like that of a partridge at full speed : 
and such a bird captures its prey by chasing after it with wonderful impetuosity, but not at a 
single plunge like a ftilcon. Such a wing has more primaries cut, farther from their ends, and 
the markings are pretty regular and distinct bars, (c) Any ' buzzard,' as a Buteo, a heavy and 
comparatively slow or even lumbering bird in flight, taking its prey by surprise and merely 
dropping on it without special address, has many or most of the primaries cut, fiir from their 
ends, and the tendency of the markings is to fuse and blend in large irregular masses of color, 
the sharp markings of Falco or Accipiterhemg thus dissipated. Of course there are exceptions, 
as well as every possible gradation, in the case ; but if one will compare the wing of Circus or 
Arcliihuteo with that of Accipiter and Falco, he cannot fail to perceive the point I raise. The 
tail is in somewhat like case. In the most noble birds of prey it is very stilf and strong, with 
almost lanceolate feathers, sharply spotted as a rule ; in a hawk, longer and weaker, still 
regularly barred ; in a buzzard generally (there are marked exceptions) of medium length and 
strength, with the markings tending to merge in large areas of color, just as those of the 
wings do. 
It may be remarked further, without special reference to what has preceded, that in large 
and difficult genera, as Buteo for example, the best specific characters may be afibrded by the 
markings of the tail. These are usually quite difterent in young and old birds; but are among 
a hawk's most specific credentials, after the mature plumage is assumed, even when the rest of 
the plumage varies greatly, or is subject to melanism, erythrism, etc. In fine, many hawks 
are best known by their tails. Melanism in frequent in FalconidtE ; erythrism is not (just the 
reverse of the case of Strigidce). The further generalization may be made, that the coloration 
of the under parts of Falconidoi is more distinctive of species than that of the upper parts; and 
that when these parts are barred crosswise in the adult they are streaked lengthwise in the 
young. Sexual differences are rather in size than in color, such a case as that of Circus being- 
exceptional. 
Analysis of Subfamilies. 
Scapular process of coracoid reaching clavicle. 
Upper mandible toothed, lower mandible notched FALCONI^'^ 
Mandibles without tooth or notch POLYBORIX^ 
Scapular process of coracoid Jiot reaching clavicle. 
Face with a ruff somewhat as in owls Circin.'e 
Face without rutf. 
Tarsus approximately equal to tibia in length ; rounded wings little longer than tail AcciriTRiN.E 
Tarsus decidedly shorter than tibia. 
Tail forked, or much shoi'ter than the long pointed wings MiLVix^ 
Tail not forked, moderately shorter than the obtuse wings ButeoisJN^ 
