306 HERONS, “SLORLS,. AND IBISES. 
appears to be generally found singly or in pairs. Resembling in many of its 
general habits the ibises, the hammer-head when passing from lake to lake 
flies strongly and ascends high into the air; and is reported to utter a kind of 
croaking cry. The most interesting feature connected with this singular bird is, 
however, its nest. This is a huge, dome-like structure of sticks, so firmly built 
that it will bear the weight of a man, and frequently from a yard and a half to 
two yards or more in diameter. Generally placed in a fork of a tree near the 
ground, although sometimes in a rocky cleft, the nest has a single entrance 
situated on its most concealed side. Internally it contains three chambers—a hall, 
a drawing-room, and a sleeping apartment, with entrances so small that the bird . 
can only creep in. The sleeping-chamber occupies the highest portion of the nest, 
in order to be safe from floods, and in it, upon a bed of water-plants, are laid the 
white eggs, which are from three to five in number and are incubated by each 
parent in turn. The middle chamber serves for the young when they are too big 
for the inner one, while the hall is used as a look-out station. In Angola the nests 
of other birds are said to be taken by the hammer-head. The chief food of these 
birds appears to consist generally of fish; but in some districts, at least, river- 
mussels, frogs, lizards, small snakes, and worms and insects, constitute a portion 
of the diet. Although the two members of a pair do not always remain together, 
they appear to be associated for life; and at times the two birds, or occasionally 
three, will go through a peculiar kind of dance-like performance. Everywhere 
these birds are mainly crepuscular, and are but seldom seen in the full daylight. 
THE STORK TRIBE. 
Family CICONIIDA. 
The storks may be distinguished externally from the herons by the absence of 
pectination on the inner edge of the claw of the third toe, by the metatarsus being 
covered with reticulate scales, by the absence of powder-down patches on the 
sides of the rump, and by the feathering on the under surface of the lower 
mandible not extending in advance of the line of the nostrils. In the skeleton the 
furcula, which is generally U-shaped, is characterised by the absence of any 
median projection into its angle. All storks have short triangular tongues, 
whereas herons (except the boat-bill) have long ones; and, with the exception of 
two genera, they are characterised by the rings of the bronchial tubes being 
complete. There are certain other anatomical features, into the consideration of 
which it will be unnecessary to enter. As supplemental characters, it may be 
mentioned that in all the members of the family the body is plump; the beak in 
the form of a long compressed cone, with a sharp point, but may be either turned 
up at the extremity, or gaping in the middle; the leg is long, strong, and naked 
for a considerable distance above the ankle; the toes are short, and the three front 
ones connected by a short basal web; the wings large; and the short and rounded 
tail with twelve feathers. The contour-feathers of the head and neck may be 
either narrow and elongated, or short and rounded; while in some cases they may 
become woolly or hairy, or even, in old age, with horny lance-like tips. The two 
