This section is from the book "The Speaking Parrots: A Scientific Manual", by Dr. Karl Russ. Also available from Amazon: The Speaking Parrots.
Psittacus Ducorpsi, Hmbr. et Jacq.
Ducorps Cockatoo (Ger., Ducorps' Kakadu oder Ducorps' Kakatu; Fr., Cacatois de Ducorps; Dut., Ducorps' Kakketoe) - Distinguishing Marks - Habitat - Domestic Character.
This bird has a short erect crest, the point being turned away from the front, the reverse side of the feathers and both sides at the base being light yellow (in some specimens a pale reddish-yellow), otherwise the whole of the body is white, except the inner side of the flights, which is pale yellow, and the inner side of the tail feathers, which is of more pronounced yellow; sometimes the whole of the otherwise pure white plumage has a yellowish tinge; the beak is greyish-white; the cere and nostrils are set with little white feathers; the eyes are black, dark brown, or dark red, a large bluish-white circle round the eye; the feet are greyish-white, the scales and claws blackish. The size is rather larger than a jackdaw (length, 12in. to 13 1/2in.; wings, 8 3/4in. to 10 3/8in.; tail, 5 1/4in. to 5 5/8in.). It resembles Goffin's Cockatoo, but is distinguished by the shorter crest, and by the feathers on the head, throat, and breast being other than red at the base. It may be distinguished from the Red-vented Cockatoo by the absence of the red coverts underneath the tail. It is indigenous to the Solomon Islands. It was described and drawn by Hom-bron and Jacquinot in 1830, but is still rare both in museums as a stuffed specimen as well as alive among the dealers. Layard observed them in the Island of Bougainville on the mangrove trees, on the fruit of which they subsist. Strange to say, it has nearly always happened that the birds which have come into the possession of the fanciers - for example, Mr. Fiedler, Mr. Linden, and the Baroness Sidonie von Schlechta, of Vienna - have been hens, which have laid several eggs. The above-named lady describes one as follows: "I brought the cockatoo home wrapped up in a cloth, but the way it dashed itself against the bars of the cage did not lead me to expect the establishment of a very friendly footing between us. But how astonished was I when, after I had put off my hat, it seemed quite quiet, and allowed me to take it on my hand. The puzzle was afterwards solved, for whenever I put on my hat, or wore a bandage on my head for headache, it became either shy or wicked; the dealer from whom I had bought it used to wear a round cap, and towards this man the bird had borne a grudge. It was only after a length of time that it began to know me with that or other hats, and when I called to it would recognise me and nod expressively. Its favourite food was roast potato, nuts, and oats, as well as a gruel made of polenta flour and water. It said several words and sentences very prettily, in a gentle childlike voice, but quickly and vivaciously." Mr. Linden also writes of a Ducorps' Cockatoo which he had, that it was tame and affectionate, and was especially charmed by the sound of a lady's voice; it laid an egg every year.
 
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