I did not then suspect _that it would take me nearly a year_ to be absolutely certain that this sound was uttered by an extremely shy and restless kind of cuckoo!
This sound of the African night always made the strongest impression upon me, and remains indelibly in my memory. All that one heard from near at hand, or from the distance miles away, had its origin not in man’s voice or in human activity of any kind, but most come from birds and beasts to a great extent unknown to us. One had to interpret, to conjecture, to build up theories. Often one struck upon the correct solution. But often enough, too, the interpretation one accepted proved to be false, and then one’s anxiety to find out the true solution, aroused anew, was doubly keen. The first time I heard it, I had no difficulty in interpreting for myself the cry of the monkeys harassed in the night by leopards, a screaming of a kind one cannot easily forget, plainly expressing the greatest terror. The first time one heard the neighing of the herds of zebras it was much more difficult to recognise the sound, and the gobbling cry of the ostrich had at first a still stranger effect. But as soon as I had heard the voice of the zebras a few times, it was clear to me that the extinct _quagga_ of South Africa must have derived its name from its cry. If one puts the accent on the second syllable, and pronounces the _g_ softly and deep in the throat, one has, as one repeats it, a wonderful reproduction of the cry of the zebra as I heard it myself.[41]
What a pity that all this cannot be put on permanent record by some such apparatus as a gigantic phonograph! But unfortunately we are still a long way from such a possibility.
No one will be surprised at my keeping specially in mind that endlessly melancholy cry of the cuckoo in the darkness. How lonely and empty our German woodlands would seem without the cuckoo and the cuckoo cry! As a matter of fact the African primeval forest _never_ hears the same cry that has become so clear to ourselves. Our cuckoo, migrating in a few days all the way from the north to the equator, flies in restless haste through wood and plain, but _he is silent_. His cry is heard only in our country at home. But in the East Africa district of Pori, amongst many other cries those of two species of cuckoo are heard in rivalry. These are the sickle cuckoo--the “Tipi-tipi” of the Swahili--a reddish-brown fellow that flutters in heavy flight everywhere about the bush, the reedy bogs and hill-slopes; and the solitary cuckoo (_Cuculus solitarius_, Step.), about whose cry I was for a long time mistaken. The unceasing, low cry of the former, the sickle cuckoo, if it is heard even a few times, can never again be forgotten. It sounds like--“Dut-dút--dududu--dut-dút.” One hears it by day and also in the darkest night, contrasting strongly with the sharply defined, clear note of our European cuckoo, though the latter listens in silence to the cry of his cousins all through the winter under the equator. This cry seems to me, with its low, dull, softly prolonged tones--so different from the louder cry of its northern relative--to be quite in keeping with its mysterious tropical home. For the sickle cuckoo knows all its deepest mysteries, and no bird ranges so unweariedly through the densest thickets and over the most inaccessible regions. In the most hidden, solitary, and unknown spots[42] it would come fluttering up from the ground at my feet, often startling me. It seemed to me as if the bird wanted to call my attention to newly discovered mysteries, as its “Dut-dút--dududu--dut-dút” came sounding to me, now here, now there, low, soft and melodious, by day under the brooding noonday heat, and just the same in the midnight hours.