1884～'85年になされたトキの羽色変化に関するM.Berezovskyの観察記録

抄録

1. M. Berezovsky who took part in the west China expedition under the command of G. N. Potanin, 1884-1887, observed colour change on plumage of Japanese Crested Ibis near Hoi-cyan, Gan-su province, west China, 1884-1885.
2. M. Berezovsky and V. Bianki (1891) described the result of Berezovski's observations as following items. a) All Japanese Crested Ibises observed in December have white plumages. b) In the end of January some of the birds have faint grey tint on the head and neck. c) In February some greyish birds are seen more often. By the end of this month some white ibises are met as exceptions. d) It is confirmed that the colour change takes place on the same birds, and that Nipponia nippon, var, sinensis described by A. A. David and M. E. Oustalet (1877) because of its grey plumage is nothing but Nipponia nippon itself with summer apparel. e) Spots where formation of black pigment takes place are found in the skin of head and neck. These are observed at the external surface of the skin, but particularly pronounced on the internal side. f) The change of colour begins in the end of January and is over by March, but during the whole time interval the behaviour of ibises is without any sign that would indicate beginning of the breeding period. g) Its plumage is white only in autumn and winter; they are grey in spring and summer. This fact is agreed by almost all data from China, Ussury-area and Japan which have descriptions of plumage colour and the time of observation or hunting. h) Nothing is known in the autumn change of apparel or moulting of the birds.
3. This description did not call any attention to every ornithologist except Karl Deditius (1897) who mentioned "Das mitgebrachte Material beweist vollkommen, daβ Ibis sinensis ein Sommerkleid von Nipponia nippon ist, " and Ernst Hartert (1936) who referred to Berezovski's pronouncement, but did not accepted it.
4. The author is grateful to Dr. Irina A. Dubrovo, Palaeontological Institute of the Academy of Sciences, U. S. S. R., for searching for this description and sending it to him and to Miss Kimiko Koshikawa for her help in translating old Russian of this description into Japanese.