128 
GENERAL ORNITHOLOGY. 
as a core to the claw. The difference in the lengths of the several phalanges, like that of 
the digits themselves, makes the toes more efficient in grasping, since they thereby clasp more 
perfectly upon an irregular object. The design and the principle are the same as seen in the 
human hand, in which model instrument the digits and their joints are all of different lengths. 
The Position of the Digits, other than in respect to their direction, is important. In 
all birds the front toes are inserted on the metatarsus on the same level, or so nearly in one 
horizontal plane that the difference is not notable. The same may be said of the hind toes 
when they are a pair, as in zygodactyle birds. But the hind toe, or hallux, as it is often 
called, when present and single, varies remarkably in position with reference to the front toes ; 
and this matter requires special notice, as it is important in classification. The insertion of 
this digit varies, from the very bottom of the tarsus {metatarsus), where it is on a level with 
tlie front toes, to some distance up the bone. When the hallux is flush with the bases of 
the other toes, so that its whole length is on the ground, it is said to be incumbent. When 
just so much raised that its tip only touches the ground, it is called insistent. When inserted 
so high up that it does not reach the ground, it is termed reiiiote (amotus) or elevated. 
But as the precise position varies insensibly, so that the foregoing distinctions are not readily 
perceived, it is practically best to recognize only two of these three conditions, saying simply 
'Miiudtoe elevated," when it is inserted lairly above the rest, and ''h'md toe not elevated," 
when its insertion is flush with that of the other toes. In round terms : it is characteristic of 
all insessorial (Lat. insedo, 1 sit upon) or perching birds to have the hind toe dovtn ; of all 
other birds to have it UP (when present). The exceptions to the first of these statements are 
extremely rare ; among North American birds they are chiefly furnished by certain genera of 
Caprimidgidce, perhaps also of Cypselidce, and of Cathartidce. But among other Raptores 
besides Cathartidce, especially certain owls (Striges), and in some of the pigeons (Coliimhidce) , 
the hind toe is not quite down, or is decidedly uplifted (as in Starnoenas, for example). It is 
elevated in all our rasorial birds (Gallince); elevated in all our waders excepting the herons 
and some of their allies (Herodiones) , though not very markedly so in the rail family {Rallidfje). 
It is elevated in all swimming birds, whether lobe-footed or completely or partly web-footed, 
but in the totipalmate order (Steganopodes), where the hallux is lateral in position and 
webbed with the inner toe, the elevation is slight. Now since, curiously enough, the only 
, ones of our insessorial genera (see above) that have the hind toe up, have also little webs 
between the front toes — since some Raptores are our only other insessorial birds with any 
such true webbing — since herons and some of their allies are our only birds with such 
webbing that have the hallux down — the following rule is perhaps infallible for North 
American birds : Consider the hind toe UP in any hird ivith any true webbing or lobing of the 
front toes, excepting herons and some of their allies and some birds of prey. The converse 
also holds almost as well ; for our only birds with fully cleft anterior toes and hind toe up, are 
thtp rails and gallinules (Rallidce') , the black-bellied plover {Squatarola helvetica), our only 
four-t(>ied plover, the turn-stone {Strep)silas intei'pres), the American woodcock (Philohela 
minor), tht-^ European woodcock (Scolopax rusticula), Wilson's snipe {Gallinago wilsmii), and 
most of the sauidpipers {Scolopacidce) . If the sense of this paragraph is taken in, the student 
who wishes to us»e my artificial "key" will seldom be puzzled to know whether to take the 
toe up or down. » 
The Hallux has otvher Notable Characters. — It is free and simple, in the vast majority 
of birds : in all insessorial b\irds, nearly all cursorial (Lat. cursor, a courser), and most natatorial 
(Lat. natator, a swimmer) fc^rms. Its length, claw included, may equal or surpass that of the 
longest anterior toe; and generally exceeds that of one or two of these. It is never so long as 
when incumbent ; when thus do^v^rn on a level with the rest it also acquires its greatest mobility 
