A History 
of Birds. 
( : 7 ) 
THE BIRD WORLD. 
skin thrown into a series of fowls. A 
stomach of this kind is known as a 
gizzard, but in birds which feed on 
animal food, such as Hawks and Gulls, 
for example, there is no “ gizzard ” in 
the strict sense of the term, the walls of 
this region of the stomach being thin 
and soft. 
The Work of the Gizzard. 
Where a true gizzard is developed, 
sharp stones and sand are deliberately 
swallowed by the bird, and these, aided 
by the muscular contractions of the 
thickened walls, grind the hard grain and 
seeds into small pieces, thus enabling the 
work of digestion to be completed in the 
intestines. It would seem that even 
flesh-eating birds require to introduce 
foreign substances—that is to say, sub¬ 
stances which are not swallowed to serve 
as nourishment — into this second 
stomach to ensure healthy digestion. 
Hawks kept in captivity, for example, 
will not thrive unless they are supplied, 
at least at frequent intervals, with birds, 
mice, rats, and so on in their natural 
state, so that they may swallow the fur 
and feathers, and form what are known 
among falconers as “ castings,” from the 
fact that these indigestible morsels are 
later thrown up again in the form of 
pellets. Owls similarly form pellets of 
this description, and so also do many 
other birds that are not commonly sup¬ 
posed to indulge in this practice. The 
Rook is one of these. The pellets of this 
bird, of which I have examined a great 
many, take the form of oval masses 
formed of husks and bits of straw and 
other vegetable matter. The Great 
Crested Grebe and Dabchick appear to 
be peculiar, in that they make a practice 
of swallowing their own feathers. 
From the second stomach or gizzard, 
the broken-up food passes into the 
“ small ” intestines. The first portion of 
this tube forms a U-shaped loop, known 
as the “ duodenum,” and enclosed be¬ 
tween the loops of the U is a gland 
known as the “pancreas.” 
The Alkaline Juices. 
The digestive juices formed by this 
gland are conveyed to the gut by means 
of tubes known as ducts, and, in addi¬ 
tion to these, this region of the gut re¬ 
ceives similar ducts which convey the 
bile or gall from the liver, or from the 
gall-bladder when this is present. These 
juices of the pancreas and gall-bladder 
are strongly alkaline, and serve to coun¬ 
teract or neutralise the acid nature of 
the milky mass to which the food, when 
it enters the duodenum, is reduced. 
Thereby, it is rendered fit for absorption 
by the succeeding portion of the intes¬ 
tine. After the intestines have taken up 
and passed into the blood, or into the 
special vessels known as “ lacteals,” all 
the nourishment which the fluid matter 
is in the tube of the gut, the indigestible 
waste matter is passed on to the large 
intestine, and finally is ejected as 
“ faeces.” At the junction where the 
small passes into the large intestine there 
occurs, in a large number of birds, a 
pair of tube-like blind pouches, known 
as the coeca, or blind gut. The func¬ 
tion of these organs is not yet thoroughly 
known, but here the final work of diges¬ 
tion is carried out. In many birds the 
cceca are of great length, as in the Fowls 
of Game Birds, and in the Rhea among 
the Ostriches; in others they are degene¬ 
rate, and often are completely sup¬ 
pressed. In the Herons but one is 
found, and this only in the form of a 
minute pouch; in the perching birds 
(Passeres) the cceca are also represented 
only by vestiges. The large intestine 
terminates in a series of chambers, or, 
rather, is separable into three compart¬ 
ments—one behind the other. The first 
is known as the coprodeum; the second 
as the urodeum, into this the urinary 
tubes from the kidneys open, and also 
the oviducts and sperm ducts, the tubes 
which convey the fertilising sperm cells 
of the male, and the eggs of the female; 
while the third compartment lodges the 
genital organs, and serves as the common 
exit of both fcecal and genital products. 
The Tart the Tongue Plays. 
So far, my readers may remark, no 
mention has been made of the tongues of 
birds. This omission shall now be 
