PICIB^: WOODPECKERS. 
477 
27. Family PICID^ : Woodpeckers. 
Feet perfectly zygodactyle by reversion of the 
fourth toe (in two genera the first toe wanting) ; 
tail-feathers rigid, acuminate; bill a chisel. This 
expression will serve for the recognition of any 
woodpecker (compare diagnoses of previous Pica- 
rian families). Wing of 10 primaries, the 1st 
quite short or even spurious, the wing-formula 
being quite as in most passerine birds — a crow 
or thrush, for example. Greater row of second- 
ary coverts short, as in passerine birds at large. 
Tail of 12 rectrices, but the outermost 2)air rudi- 
mentary, lying concealed at the base of the tail 
Fig. 328. - European Spotted Woodpecker {Picus between the penultimate (now exterior) and next 
major), reduced. (From Dixon. ) pajr^ SO that there appear to be but 10, as usual 
in Picarian birds (a strong peculiarity). Tail-feathers very stiflf and strong, with enlarged 
elastic shafts, and acuminate at the end. Tarsi scutellate in front, on the sides and behind 
variously reticulate. Toes strongly scutellate on top. The usual ratio of the toes is : 1st 
(inner posterior) shortest ; 2d (inner anterior) next longer ; 3d (outer anterior) longer ; 4th 
(outer posterior) longest of all (in most typical species ; in some, however, scarcely or not 
equalling the 3d in length). The basal joints of the toes are abbreviated. There is a very 
unusual arrangement of the flexor tendons of the toes (shared, however, among Toucans, 
Scansorial Barbets, and Jacamars). 
These birds have been specially studied, with more or less gratifying success, by Malherbe, 
Sundevall and Cassin. There are nearly 250 well determined species, of all parts of the world 
except Madagascar, Australia, and Polynesia. Their separation into minor groups has not been 
agreed upon ; our species are commonly thrown into three divisions, which, however, I shall 
not present, as consideration of exotic forms shows how the genera are interrelated, and how 
nice is the gradation in form between the Ivory-bill and the Flicker, which stand nearly at 
extremes of the family ; the little diversity of which is thereby evident. One of our genera, 
without very obvious external peculiarities, stands apart from the rest in the character of the 
tongue. In ordinary Pici the horns " of the tongue are extraordinarily produced backward, 
as slender jointed bony rods curling np over the skull behind, between the skin and the bone, 
to the eyes or even further ; these rods are enwrapped in highly developed, specialized muscles, 
by means of which the birds thrust out the tongue sometimes several inches beyond the bill 
(figs. 73, 74). This is not the case in Sphyropicus, where the hyoid cornua do not extend beyond 
the base of the skull, and the tongue, consequently, is but little more extensible than in ordinary 
birds. The tongue of Sphyropicus is beset at the end by numerous brushy filaments, instead of 
the few acute barbs commonly observed in the family. The same or a similar condition of the 
parts is observed in Xenopicus. In most of our species the bill is perfectly straight, wide and 
stout at the base, tapering regularly to a compressed and vertically truncate tip, chisel-like, and 
strengthened by sharp ridges on the side of the upper mandible — an admirable tool for cutting 
into trees; and in all such, the nostrils are hidden by dense tufts of antrorse feathers. In 
others, like the Flicker, the bill is smooth and barely curved ; the tip is acute and the nostrils 
are exposed. There is a regular gradation in form between those with the most and the least 
chisel-like bills. The former are more stocky-bodied birds, with larger heads in comparison 
with the constricted neck, as any one may satisfy himself by skinning a Pileated or Hairy 
Woodpecker, and trying to pull the skin over the head — an operation M^hich may be performed 
on a Flicker. The ridges of the bill, the bevelling of the end, the nasal tufts, and usually the 
