Japanese Journal of Ornithology
Online ISSN : 1881-9710
Print ISSN : 0913-400X
ISSN-L : 0913-400X
Volume 49, Issue 1
Displaying 1-8 of 8 articles from this issue
  • Hiroshi UCHIDA, Hisashi NAGATA
    2000 Volume 49 Issue 1 Pages 1-8
    Published: July 25, 2000
    Released on J-STAGE: September 28, 2007
    JOURNAL FREE ACCESS
    In order to conserve local bird populations knowledge of local population structure and mortality is essential. In Japan, the mortality is known little because researchers have not been able to access and analyse data stored within the Japanese ringing database. In order to evaluate the mortality and population structure a colour banded population of Japanese wagtail Motacilla grandis was studied on the Toki River between 1989 and 1995. In this species each pair defends a territory throughout the year. In this study 74% of the population stayed in the same territory as the previous year. The remainders only shifted their territories an average distance of 312.5 ± 46.3 m (mean ± SE). There was no difference between sexes with respect to age dependent dispersal or site tenacity.
    Survival rates were estimated using Lack's and Haldane's methods. Lack's method gave a survival estimate of 0.58 ± 0.022 (SE) while Haldane's gave an estimate of 0.63 ± 0.021 (SE). Males showed slightly higher annual survivourship, although this was not statistically significant. The estimate of survival (approximately 60%) closely corresponded with the adult proportion of the population (0.62). Since the number of territories remained stable throughout the study period, this result might have shown a stable age structure in this population. To make an effective conservation plan, further study of patterns of natal dispersal in M grandis would be necessary.
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  • Katsutoshi MATSUNAGA, Aoi MATSUDA, Hiromi FUKUDA
    2000 Volume 49 Issue 1 Pages 9-16,63
    Published: July 25, 2000
    Released on J-STAGE: September 28, 2007
    JOURNAL FREE ACCESS
    We studied the dynamics of the colony sites of Grey Herons Ardea cinerea from 1960 to 1999 in Hokkaido, Japan. According to our estimates, 66 colonies existed, 13 of which disappeared. The number of colonies increased rapidly from about 1980 onwards. The rate of increase in the number of colonies per year grew from 0.40 before 1980 to 2.05 after 1980. By contrast, the mean number of nests per colony decreased from 170.5 to 48.4. It was also found that in recent years the proportion of inland colonies has increased. The mean number of nests was 48.8 in inland colonies and 107.0 in coastal colonies. With natural and artificial changes occurring to the environment, new small-scale satellite colonies appear to have been established at inland sites, leaving the old large core colonies in coastal areas. We suggest, therefore, that core colonies should be protected, with the highest priority, for effective conservation of Hokkaido's Grey Heron population.
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  • A Food-addition Experiment
    Yoshio SHIMIZU, Masahiko NAKAMURA
    2000 Volume 49 Issue 1 Pages 17-30,64
    Published: July 25, 2000
    Released on J-STAGE: September 28, 2007
    JOURNAL FREE ACCESS
    To examine the effects of food availability on the organization of mixed-species feeding associations in Tundra Swans (Cygnus columbianus), Common Pochards (Aythya ferina) and Northern Pintails (Anas acuta), we observed their social and feeding behavior before and after the addition of artificial food (rice grains). The feeding associations occurred when the swans paddled their legs underwater to forage for sinking food. Pochards dived under paddling swans and Pintails foraged around the feeding associations of the two species. Before the addition of food, Tundra Swans showed the largest increase in dipping frequency in the three-species associations because more sinking food was stirred up by the feeding actions of Pochards. Pochards were also found to dive more frequently and for shorter periods in the three-species associations than solitary. Pintails in the mixed-species associations obtained more food by using three feeding techniques and by shortening the distance moved while dabbling. After the addition of rice grains, association size and aggressive interactions increased. Because frequent diving by many Pochards disturbed the feeding swans, the swans in the three-species associations had the lowest dipping frequency. However, Pochards and Pintails gathered around feeding swans despite the swans' aggressiveness and they still achieved greater feeding frequencies in the three-species associations than solitary. Therefore, the functional significance of mixed-feeding associations before the addition of food was based on mutualism but, after rice grains were provided, it was based on parasitism in which the hosts were Tundra Swans and the parasites were Pochards and Pintails. The most abundant participants in the three-species associations were Pochards and Tundra Swans were mainly aggressive toward them. Adding food led to an increase in the number of Pochards, which was costly for Tundra Swans. We concluded that the organization of mixed-species associations depended on the number of Pochards joining the feeding association.
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  • Shin-Jae RHIM, Woo-Shin LEE
    2000 Volume 49 Issue 1 Pages 31-38,65
    Published: July 25, 2000
    Released on J-STAGE: September 28, 2007
    JOURNAL FREE ACCESS
    The aim of this study was to examine the changes in breeding bird communities resulting from change in habitat structure caused by forestry. Research was conducted in a natural deciduous forest within the Pyoungchang national forest, Kangwon Province (N 37°27′, E 128°29′), in the Northeastern part of South Korea, from April to June, 1996. Three 8-ha areas with differing degrees of deforestation were selected for territory mapping of breeding bird communities. Vegetation characteristics, vertical structure of habitat (foliage height profile), and diameters at breast height (DBH) distribution were measured in each study area. The characteristics of the breeding bird communities and their niche relationships were surveyed. The relationships between habitat structure and breeding bird communities were also examined. The dominant tree species in the study area were Quercus mongolica, Ulmus davidiana, Acer mono and Fraxinus rhynchophylla. The vertical structure of the forest differed among the study areas. The number of trees per hectare, tree species diversity, and range of DBH decreased with the degree of forest cutting among the areas studied. Bird species diversity, breeding density, species richness, and guild structures also differed among study areas. The hole-nesting and canopyforaging guild was dominant in intact natural forest, whereas the bush-nesting and bush-foraging guild was found to be more prevalent at areas where a few trees had been felled. We found that the structure of a forest seems to be an important determining factor for a breeding bird community. Therefore, the interaction between the structure of a forest and its bird community should be considered in forest management for conservation of bird communities and their habitat.
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  • Sumio NAKAMURA
    2000 Volume 49 Issue 1 Pages 39-50
    Published: July 25, 2000
    Released on J-STAGE: September 28, 2007
    JOURNAL FREE ACCESS
    During the breeding season, Carrion Crows Corvus corone and Jungle Crows Corvus macrorhynchos widely overlap each other in suitable habitats. During the 1991 breeding season their nest site characteristics were studied in Takatsuki City, Osaka, Japan. The study area comprised urban areas, adjacent farmland and woodland. I found that 52% of Carrion Crow nests were built in evergreen trees, 25% were in deciduous trees and 23% were placed on artificial structures. In many cases, nests were built in sparsely wooded areas. Most Jungle Crow nests were located in evergreen trees (92%), 3% were in deciduous trees and just 5% were built on artificial structures, and almost all nests were found in large areas of woodland. The average distance between a nest and the edge of the forest was 20.3m for Carrion Crows and 113.7m in the case of the Jungle Crow. As a general rule, it was more difficult to discover the nests of the Jungle Crow than the nest of the Carrion Crow. The ratio of cropland in the area around the nest site (r<150m), was larger in the Carrion Crow than in the Jungle Crow. The ratio of woodland was extremely small in the Carrion Crow and was variable in the Jungle Crow. Almost all of the Jungle Crow nests (81%) in evergreen trees were in areas of extensive woodland. In contrast to this, 85% of Carrion Crow nests were found in another combination of micro-habitat, including deciduous trees, artificial structures, medium or small areas of woodland, or small groves of trees. The feeding behaviour and the preference for nest site concealment differed considerably between the two species. These differences may induce nest site segregation.
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  • Yukiko NOTA
    2000 Volume 49 Issue 1 Pages 51-54
    Published: July 25, 2000
    Released on J-STAGE: September 28, 2007
    JOURNAL FREE ACCESS
  • Hisashi NAGATA, Ayumi ISHIMOTO
    2000 Volume 49 Issue 1 Pages 55-58
    Published: July 25, 2000
    Released on J-STAGE: September 28, 2007
    JOURNAL FREE ACCESS
    The authors captured a Savannah Sparrow at Myoginohana (35°57′28″N, 14°27′42″E) in Sakuragawa Villege, Ibaraki Prefecture, central Japan, on April 3, 1998. The bird was identified as first-year bird, because it had greater / median covert with broad beige edge and pointed rectrices, and because pre-breeding moult had occurred on parts of tertials, rectrices, head, breast and upper/ under coverts.
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  • Katsura K. KAWANO, Hitoha E. AMANO, Kazuhiro EGUCHI
    2000 Volume 49 Issue 1 Pages 59-61
    Published: July 25, 2000
    Released on J-STAGE: September 28, 2007
    JOURNAL FREE ACCESS
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