The Japanese White-eye, Zosterops japonica, are known as a nectar robber from several kinds of introduced flowers (Ueda & Nagano 1991, Ueda & Karaki 1997). Hibiscus flowers, pierced by white-eyes for nectar robbing, were surveyed at 49 locations in 21 southern islands belonging to Izu, Bonin, Osumi, Tokara, Amami, Ryukyu, Daito, Miyako, Yaeyama Islands, and Formosa, from 1991 to 1998. Out of 6413 flowers checked, 1947 (30.4%) had holes and slits in the bottom of the flowers, having been pierced by white-eyes.Nectar robbing did not occur in northern islands located higher than 290 N in latitude. The nectar robbing behaviour was restricted to the population inhabiting the sub-tropical islands; however, it was not observed on the Yaeyama Islands and Minami-daito-jima (Daito Islands). Such robbing behaviour was not observed between native plants on any of the islands.
Histopathological and chemical examinations were conducted on a Middendorff's Bean Goose (Anser fabalis middendorffii), found dead at Fukushima-gata, Niigata Prefecture, Japan.This bird was thin, showing severe atrophy of the pectoral muscle, and was diagnosed as having acute lead poisoning due to ingestion of spent lead shot. The main gross findings were the bilestained liver and intestines, lead pellets in the gizzard, and proventricular impaction. Histopathologically, hemosiderosis of the liver and spleen was pronounced. The lead concentration of the liver registered 41μg/g wet weight and was significantly higher than the control value of 0.10 μg/g. High values of lead concentration were also found in the pectoral muscle (0.80), kidney (27), intestine (16), scapular bone (170), and blood (11). The present study is the first to provide chemical and histopathological evidence for acute lead poisoning in the bean geese wintering in Japan.
The reasons for the success of certain, alien avian introductions into Japan, and the possible impact of the presence of exotic bird species on Japan's native birds are discussed, with reference to historical reviews of introductions to the New Zealand, Hawaiian, and the Mascarene islands. Among the major taxa commonly introduced are the Galliformes as game, and the Psittacif ormes and Passerif ormes (particularly Estrildidae and Ploceidae) for aesthetic purposes.The majority of exotic species occurring in natural habitats in Japan have either escaped accidentally from captivity, or they are pets that have been intentionally released.The exceptions are Phasianus colchicus karpowi and Bambusicola thoracica that were intentionally and systematically released as game for shooting. P.c.karpowi, B.thoracica, Columba livia, Psittacula krameri manillensis, Garrulax perspicillatus, G.canorus, Leiothrix lutea, Amandava amandava, Acridotheres tristis, and Pica pica have all established long-term self-sustaining populations.The majority of successful introduced species are generalists in terms of their food requirements and they prefer open habitats, although L. lutea and G.canorus are notable exceptions that have increased rapidly in native broad-leaved forests in recent years.So far, there appears not have been any serious declines in the populations of native birds as a result of the presence of these exotic species, however, some native species remain at risk from hybridisation, from competition for food or nest sites, and from the transfer of epidemic diseases, as a result of the introduction of exotic species.Information on the importation, the ecology, and the population dynamics of exotic species is badly needed.
Introduced Red-billed Leiothrix have recently invaded into Japanese forests. We collected fecal samples from Red-billed Leiothrix in autumn 1993 on Mt. Tsukuba, central Japan. 217 seeds were found in the samples, representing 10 species of canopy trees, shrubs, vines and understory herbs. The majority of the seeds were from berries, but we also collected a nut from Carpinus tschonoskii. Since nuts have no fruit pulp and leiothrix seems not to be able to digest seeds, the Carpinus nut was probably swallowed accidentally. However, such accidental feeding on nuts by frugivorous birds may still result in effective seed dispersal. The occurrence of a diversity of seeds in Red-billed Leiothrix fecal samples suggests that this species may affect plant communities in areas which it has invaded through seed dispersal.
In Nov.1994, the Japn Falconers Association constructed two manmade nests for Goshawk in the hilly districts of the western part of Tokyo. One was used by a pair of Goshawk during the 1995 breeding season. The nest (Fig.1), about 1m in diameter, was set at the height of about 18m in a fir tree. The pair succeeded in laying egg and having them hatch, but the young were lost before leaving the nest.
Fruit of the Chinese tallow-tree Sapium sebiferum have white sarcocarp and dehiscence in autumn. The sarcocarp dries on the branch soon after the dehiscence. We observed eight bird species eating the fruit of S. sebiferum. Two species of crows Corvus corone and C. macrorhynchos, the Grey Starling Sturnus cineraceus and the Brown-eared Bulbul Hypsipetes amaurotis swallowed the fruit and excreted the seeds. The Tree Sparrow Passer montanus, the Great Tit Parus major and the Oriental Greenfinch Carduelis sinica took only a small part of the sarcocarp and left the seeds on the branch.The Turtle Dove Streptopelia orientalis took a lot of fruits and digested the seeds.The Tree Sparrow, the Great Tit, the Oriental Greenfinch, and the Turtle Dove are not seed dispersers, but a kind of seed parasite or predator.