The Great Spotted Cuckoo of South Europe and North Africa is a species which, though parasitic, does not seem to have sunk to such a depth as the common cuckoo. Its eggs very closely resemble those of certain magpies and crows within its breeding-area, and it is in the nests of these that they are deposited. We may assume that mimicry has been resorted to, and become perfected by the same means as have accomplished this end in the case of the common cuckoo. We notice here, however, two points of difference therefrom. In the first place, from two to four eggs are left in each nest instead of one; and, secondly, the young cuckoos seem to live in perfect amity with their foster-brothers and -sisters—there is no ejection of the rightful heirs.
Having pledged themselves to a course of deception and treachery, there is no telling the lengths to which such conduct may lead. We have already seen that the bird has succeeded in laying what we may call forged eggs, but we come now to an instance where the young has also to be disguised. This is furnished by a species of cuckoo known as the Koel, inhabiting Palawan, an island in the Philippines. This bird shifts its parental duties upon the shoulders of a species of myna inhabiting the same island. Now, the mynas are black, and their young, as is often the case where both sexes are coloured alike, resemble the parents, and are black likewise. With the cuckoo the case is different. The male and female are conspicuously different in coloration, the former being black, the latter brown. In such cases it is the rule for the young to wear the livery of the female. If this rule were adhered to in the case of the cuckoo, destruction would be more than probable, for the mynas would as likely as not destroy so outrageous a departure from myna custom as a brown youngster. But the koel has proved equal to the occasion, by the simple expedient of attiring the young in the male instead of the female livery. Later on in life the rule for the exchange of plumage is reversed, and the young female doffs the temporary black dress of the male for the brown one of the adult female, instead of vice versâ.
All cuckoos, however, are not parasitic, the species known as Lark-Heeled Cuckoos—from the presence of a long, spine-like claw on the hind toe—building a nest and hatching their own eggs. They have a wide range, being found in Africa from Egypt to Cape Colony, Madagascar, India, China, New Guinea, and Australia.
Photo by J. T. Newman] [Berkhamsted.
YOUNG CUCKOO.
A young cuckoo remains in the nest till fully fledged.
As a rule, the Cuckoos are not conspicuously coloured, but some species are clad in a livery resplendent with metallic colours. These are represented by the Indian and Australian Bronze Cuckoos and the African Golden Cuckoos. One of the most beautiful of all is the African Emerald Cuckoo, in which the upper-parts are of a vivid emerald-green, whilst the under-parts are bright yellow.
Finally, we must mention the Ground-Cuckoos, which are comparatively long-legged, terrestrial forms, with small wings. One of the best known is an inhabitant of the Southern United States, from Texas to New Mexico, Southern Colorado, and California. "It has obtained the name of Road-runner," writes Dr. Sharpe, "from the speed with which it flies over the ground, some idea of which may be gained from a statement of Colonel Stevenson, that, when in Southern California, he saw, on two occasions, the ranchmen of that part of the country chase one of these birds on horseback for a distance of a mile or more at full speed, when the cuckoo, though still in advance, would suddenly stop and fly up among the upper limbs of some stunted tree or bush near the roadside, and the rider, having kept the bird in view all the way, would dismount and easily take the exhausted bird from its perch alive."
That the African Plantain-Eaters, or Touracos, are related to the Cuckoos there can be no doubt, although they do not bear any very close superficial resemblance to them. Striking in appearance and of beautiful plumage, they owe as much of the interest which now centres on them to the chemist as to the ornithologist. Long ago it was noticed that the rich crimson colour of the wing-quills disappeared after exposure to a heavy rain, having been apparently washed out—a supposition justified by the discovery still later that the water in which captive species had been bathing was strongly tinged with colour. A little more than thirty years ago these facts came under the notice of Professor Church, who, as a result of a thorough examination of the mystery, was enabled to announce the discovery of a new animal pigment containing copper, which he called "turacin."