For the one form, Cettia diphone cantans, of Bush Warbler, it is well known that the colouration of the sexes is identical and that the general size is considerably different between them, though the numerical data of wing length have not been published sufficiently. An aim of this paper is to find a sexing criterion of cantans in autumn routine ringing. The data of this paper were obtained at Otayama Bird Observatory during autumn ringing from 1974 to 1981. One hundred and twenty birds were composed of 92 first winter juveniles and 28 adults. The measurements of wing and tail lengths of these birds are given in Table 1, and Figs. 1-4. Both wing and tail lengths were apparently bimodal. Based on the frequency distribution of wing length, these birds were divided into two groups; Group-A, birds have wings shorter than 61mm, and Group-B have wings longer than 60mm. It seems that these two groups are females and males, respectively. The separation point of the sexes as a criterion was proposed: the birds have wings (1) shorter than 61mm are females, (2) longer than 62mm are males, and it is safe to write (3) 61mm or 62mm are not decidable.
A Spotted Eagle Aquila clanga was found dead on the shore of Maki-machi, Nishikambara-gun, Niigata Prefecture on February 12, 1984. Only a few records of this species were reported so far in Japan, and this is the first record both from Niigata Prefecture and along the coast of the Japan Sea. It was the female juvenile and its weight was 950g.
Between May 3 and 6, 1984, the authers did bird banding work on Mishima, an isolated island about 45km north-west of Hagi City, Yamaguchi Prefecture. During the period, they caught a Dusky Warbler Philloscops fuscatus which had been never recorded in Japan. The bird was mesured, photographed and then released.
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.