THE STUDENT,

AND

INTELLECTUAL OBSERVER.

TOURACOES AND THEIR DISTRIBUTION.

BY P. L. SCLATER, M.A., PH.D., F.R.S.,

Secretary to the Zoological Society of London.

(With a Coloured Plate.)

PROFESSOR CHURCH'S interesting article upon "Turacine," published in the first volume of this journal,* may have induced some of the readers of THE STUDENT to wish to know a little more about the family of birds which produce this curious animal pigment. I have, therefore, had great pleasure in complying with a request to put together a few notes upon some of the peculiarities of the Touracoes, and upon their geographical distribution, which offers several points of interest.

In accordance with the views of some of the older systematists, Professor Church has stated that the Touracoes form a sub-family of the Cuckoos (Cuculidae). While, however, there can be no doubt of the affinity of these two groups, the general consent of the best zoologists of the present day has raised the Touracoes to the rank of a family (Musophagidae), quite equivalent in value to the Cuculidæ, and occupying a corresponding place in the natural system. This is abundantly justifiable upon structural grounds, whether we consider the external or internal characters of the two groups. In the first place, the Cuculidæ belong to the true "Zygodactyla "—that * Vol. i., p. 161.

VOL. II.-NO. I.

is, have the toes arranged in pairs, two before and two behind, the external toe, which is in most birds directed forwards, being usually turned backwards, along with the normal hind-toc, although it is in some cases more or less versatile. In the Touracoes, although there is a power of turning the outer toe backwards, this digit is usually directed forwards, and is always more or less versatile. Again, the Cuckoos have no after-shaft, or accessory plume, on their bodyfeathers, while this is always present in the Touracoes, and in the latter the tip of the oil-gland is feathered, whereas in the Cuckoos this organ is quite naked.*

Of the osteological differences between the Touracoes and the Cuckoos, no sufficient account has yet been given; but the skeletons of these two forms are easily recognizable on comparison. The palatine bones of the Musophagidæ present some curious modifications, and are stated by Professor Huxley to have a certain resemblance to those of the owls. The sternum of the Touracoes, to which M. Blanchard has devoted a chapter in his excellent (but, unhappily, unfinished) article upon this part of the bird's structure, is likewise easily distinguishable from that of the Cuckoos, and more nearly resembles that of the Toucans.

We may, therefore, fairly consider the Touracoes, or Musophagidæ, as constituting a well-marked family of the class of birds most nearly allied to the Cuckoos, and more distantly to the Toucans (Rhamphastida), Puff-birds (Bucconidæ), and Jacamars (Galbulidæ). In all these last-mentioned groups of birds, the fourth toe, as well as the first, is permanently turned backwards, just as in the woodpecker and wrynecks (Picida and Yungida), which, however, are distinguishable by other very trenchant characters. But in the Touracoes, as we have already stated, the fourth toe is versatile, and may be turned either way, being usually carried, more or less nearly, at a right angle from the first and third.

As regards habits, the Touracoes are a strictly arboreal group of birds, passing the greater part of their lives upon forest trees, and seldom, if ever, descending to the ground. They are mostly of brilliant plumage, and of moderate size-about that of a domestic pigeonand are particularly active and lively in their movements. Those in the Zoological Society's aviaries never seem to be still for a minute, being constantly engaged in flitting from one perch to another, and alternately elevating and depressing their elegant crests. Their food, in a state of nature, is mostly, if not entirely, fruit, the name of * For a complete account of the pterylographic differences of these groups, see "Nitzsch's Pterylography," Ray Society's Translation, London, 1867, pp. 90, 106.

the principal genus, Musophaga, being formed from their well-known partiality for the fruit of the plaintain (Musa). We have as yet no very authentic details as to their mode of nidification; but it is usually stated that they build in hollow trees, and lay white eggs. The sexes, as far as is known, in all species of this group are coloured alike, or very nearly so.

As in the case of other groups of birds, the Touracoes have been divided by modern systematists into numerous small genera; but it is more natural, as well as more easily intelligible, to consider them as forming only three genera, which may be distinguished among themselves by very simple characters. These arc, Musophaga, Corythair, and Schizorhis. In the Musophage, or Plaintain-eaters, the culmen of the bill, at the base, is produced into a frontal shield, which covers the forehead, and the nostrils are oval. In Corythaix, or the true Touracoes, there is no frontal shield, and the nostrils are oval. In Schizorhis, or the False Touracoes, there is likewise no frontal shield, but the nostrils, as indicated by the name, are linear in shape.

Only two of the first genus, or Plantain-eaters, are known to science, and one of these (Ross's Plantain-eater) is very scarce, but a single specimen of it having been known to occur. The other, commonly called the Violet Plantain-eater, is the most brilliantlycoloured bird of the group, and, indeed, of the whole African Ornis. The plumage is of a rich dark purple, with crimson wings and head, while the bill and head-shield are yellow and red. This magnificent bird is not unfrequently brought alive to Europe, and forms a splendid ornament to our aviaries. It does not, however, thrive very well in captivity.

The second genus (Corythaix) comprehends some ten or twelve species, which are divisible into three sections. The first of these embraces only the remarkable Corythaix porphyreolopha, discovered originally by Sir Andrew Smith in Natal, and confined to the south-eastern portion of the African continent. Dr. Kirk also met with this bird on the lower course of the Zambezi, but tells us that it does not extend into the higher country of the interior. The Purple-crested Touraco is easily distinguishable from its numerous congeners of the next section by having the nostrils quite exposed and naked, and forms a transition between the Plantain-eaters and Touracoes.

The second section of Corythaix contains nine species; amongst which are the best-known birds of the genus. In these the nostrils are always more or less concealed by the projecting frontal plumes.