The SERPENT HAWK (_Polyboroides typicus_) is a very remarkable member
of the Hawk family, inhabiting the same parts of Africa as the bird
last mentioned; a very similar species is also met with in Madagascar.
The Serpent Hawk is recognisable by the smallness of its head and body,
bare cheeks, slender beak, and enormous wings; the tail is long, broad,
and slightly rounded; the tarsi high and thin, and the toes small. The
plumage is dark greyish blue upon the upper portion of the body, front
of neck, and breast; the primary quills are black, the upper secondaries
grey, with a black spot near the tip; the tail-feathers are black tipped
with white, and have a broad white streak across the middle. The belly,
hose, and tail-covers are white, delicately marked with black. The eye is
brown, the beak black, the feet lemon colour, the cere and bare patches
round the eyes pale yellow. The male bird is one foot eleven inches and
a half long, and four feet four inches across the span of the wings;
these latter are sixteen and the tail eleven inches in length; the tarsus
measures three inches and a quarter, and the middle toe not more than one
and a half.
This species is met with throughout the woodland districts of Eastern
Soudan, where it frequents such localities as are in the immediate
vicinity of water, as it there finds in abundance the reptiles on which
it principally subsists. The manner in which this Hawk obtains its prey
is very remarkable, as it is enabled to draw its victims from their holes
by the aid of a most curious contrivance; the tarsus is so constructed
as to allow the foot to be turned in all directions, backwards as well
as to the sides, and the claws being comparatively small, the leg can
be introduced through a very narrow aperture; it is then moved rapidly
into every recess and cranny of the hole, to the inevitable discovery
of its helpless occupant. The Serpent Hawks rarely pass much time upon
the wing, and, indeed, do little more than fly from one tree to another,
exhibiting in all their habits that sluggish and unsocial temperament
common to most reptile-eating birds; they live for the most part alone,
and spend their time in perching lazily on a bough, or flitting from tree
to tree. Verreaux tells us that they will sometimes pursue small birds or
quadrupeds.
* * * * *
The succeeding families of RAPTORIAL BIRDS are distinguished by the
circumstance that, although they pursue and kill living prey, they
will likewise occasionally eat carrion; in order, however, to make the
arrangement of this heterogeneous multitude at all clear to the general
reader, we must subdivide them into several different groups.
[Illustration: EAGLES.]