520 SYSTEM A TIC SYNOPSIS. — BA PTOEES— A CCIPITRES. 



falcons; 5. Polyborince, 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 wliich have been recognized from time out of mind, in popular opinion and ver- 

 nacular language. Tn my recent revision of the North Ameiican 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 ' ftilcou, such as a 

 peregrine or a lanner, we find a strong, yet sharp wing, with the second primary longest, suj)- 

 ported nearly to the end by the first and third ; the nicking of the quills confined to a few, if 

 occurring on m<ire than one, and situated near the tip. Such a wing is as ])otent 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 whole 

 extent, or almost so. (b) Any true ' hawk,' as an Astur or Accipiter, has a rounded concavo- 

 convex wing, confening 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 falcon. 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, far fi-om 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 Accipiter heing 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 

 ArcJiibuteo 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 stifl" 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 diflBcult genera, as Btiteo 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 Falconida ; 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 Falconidce 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 difi'erences are rather in size than in color, sucli a case as that of Circus being 

 exceptional. 



Analysis of Subfamilies. 



Scapular process of coracoid reaching clavicle. 



Upper mamlible toothed, lower mamlible notched FALCONiN.ffi 



Mandibles without tooth or notch Polvbokin^ 



Scapular process of coracoid not reaching clavicle. 



Face with a riiflf somewhat as in owls Circin^ 



Face without ruflf. 



Tarsus approximately equal to tibia in length ; rounded wings little longer than tail Accipitrin^ 

 Tarsus decidedly shorter than tibia. 



Tail forked, or much shorter than the long poiTited wings Milvin^e 



Tail not forked, moderately shorter than the obtuse wings Bdteonin^ 



