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Volume 5 , Issue 2
December
Showing 1-16 articles out of 16 articles from the selected issue
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SPECIAL FEATURE  Ecology and conservation of birds of prey
  • Hiroyoshi Higuchi, Masanobu Hotta
    Volume 5 (2006) Issue 2 Pages 149-150
    Released: February 01, 2007
    JOURNALS FREE ACCESS
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  • Hau-Jie Shiu, Ken-ichi Tokita, Emiko Morishita, Emiko Hiraoka, Yinyin ...
    Volume 5 (2006) Issue 2 Pages 151-156
    Released: February 01, 2007
    JOURNALS FREE ACCESS
    In order to examine fidelity to migration route, breeding, wintering, and stopover sites, we analyzed the migration of two adult Grey-faced Buzzards Butastur indicus and an adult Honey-buzzard Pernis apivorus that were satellite-tracked in East Asia for more than two migration seasons. The Grey-faced Buzzards showed a high degree of route fidelity across seasons and years. On the other hand, the migration routes of the Honey-buzzard were distinctly different between fall and spring seasons, whereas, within each season they were roughly similar between years. All three raptors were strictly faithful to their breeding and wintering sites. They also showed fidelity to several stopover sites in which the raptors stayed for relatively long periods to replenish energy. Our findings have important implications for the conservation of the migratory raptors.
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  • Yinyin Wu, Go Fujita, Hiroyoshi Higuchi
    Volume 5 (2006) Issue 2 Pages 157-163
    Released: February 01, 2007
    JOURNALS FREE ACCESS
    The Grey-faced Buzzard (Butastur indicus) is a typical migratory raptor species in East Asia, and has suffered a population decline recently. In southern Japan, the wintering buzzards are widely distributed to the Sakishima Islands. The mainly human activity on these islands is agriculture, and the natural environments are fragmented by such exploitative land-use that produces a characteristic landscape pattern. In this study, we describe the distribution pattern and habitat selection of the buzzards wintering in the Sakishima Islands, and focus on landscape elements in order to give a basic reference for further conservation study. Ten islands were investigated during January to March 2005. We used the generalized linear mixed model (GLMM) on a set of landscape elements to model buzzard distribution in the 1×1 km grid cell within each island, and studied the relationships between the numbers of buzzard and landscape elements among islands by using the generalized linear model (GLM). The results were similar on two spatial scales, and they both suggested that the area of farmlands (sugar cane, pasture, and rice paddy), and the perimeter of forests have significant correlation with the distribution and the numbers of the wintering buzzards. Different from breeding sites where distribution was limited by critical nest resource, distribution of Grey-faced Buzzards in wintering sites was simply related to foraging habitats. We suggest that further study should focus on measuring quantitatively the relationships of different farmland types with buzzard distributions in order to make more realistic predictions about distribution when habitat is lost or shifted from one category to another.
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  • Mutsuyuki Ueta, Toshiaki Hirano
    Volume 5 (2006) Issue 2 Pages 165-169
    Released: February 01, 2007
    JOURNALS FREE ACCESS
    The breeding distribution, breeding success and nest site selection of Japanese Lesser Sparrowhawks Accipiter gularis were studied in the suburbs of Tokyo and Utsunomiya, central Japan from 1987 to 2005. The number of nest sites increased from the late 1980s to the early 1990s but decreased thereafter in both of the study areas. After the late 1990s the hawks increasingly abandoned their nests because Jungle Crows Corvus macrorhynchos attacked them. In Tokyo, few sparrowhawks bred in a large grove dominated by Jungle Crows after the mid 1990s and bred mainly in a small grove with few pine trees where they selected tree species other than pines for nesting in. In Utsunomiya, a large number of Japanese Red Pine trees remained in a small grove and there hawks used pine trees for nesting in more frequently than in Tokyo. These results suggest that the increasing population of Jungle Crows has detrimental effects on the breeding distribution, the breeding success and nest site selection of Japanese Lesser Sparrowhawks.
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  • Dennis J. I. Salvador, Jayson C. Ibanez
    Volume 5 (2006) Issue 2 Pages 171-176
    Released: February 01, 2007
    JOURNALS FREE ACCESS
    The Great Philippine Eagle Pithecophaga jefferyi is regarded as one of the most endangered eagles in the world. Habitat loss and human persecution continue to impact the species adversely. These problems are complicated further by a number of human-induced factors. Yet despite these obstacles, sustained conservation initiatives over the years have began to yield positive results. The current population status of the species and threats are outlined in this report. In situ and ex situ actions associated with the conservation of the species show how these threats are being addressed. Advances made to further our understanding of the species' biology and ecology are also discussed. With continuing success in the captive propagation of the Philippine Eagle, the program is now in the process of initiating reintroductions. This is anticipated to take Philippine wildlife conservation into its next level. Recent developments and plans to strengthen recovery goals for the species are also presented in this paper.
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  • Dewi M. Prawiradilaga
    Volume 5 (2006) Issue 2 Pages 177-186
    Released: February 01, 2007
    JOURNALS FREE ACCESS
    The Javan Hawk-eagle Spizaetus bartelsi is globally endangered species which exclusively occupies the last remnant forests of Java island, Indonesia. Studies to explore its distribution throughout the island and to uncover its eco-biology have been going on. Recent field surveys recorded new localities of the Javan Hawk-eagle at South Cianjur, West Java, at G. Sanggabuana, Karawang district, West Java and at G. Endut complex, West Java. Our understanding about this enigmatic bird of prey has been improved. Ecological research, including radio tracking, has provided information on prey species, breeding biology and the estimated home range. Small mammals such as treeshrews, squirrels, bats, rats and other small rodents are the preferred prey, but birds, snakes and lizards are also taken. The Javan Hawk-eagle may breed at anytime of the year but usually between January and July. It is sexually mature at the age of three to four years, breeds every two years and lays only one egg. Incubation lasts for 47–48 days and the young bird is fully fledged at 70 days old. Both parents look after the nestling. Some juveniles stay around the parent's territory until the following breeding season. The home range of non-breeding males monitored by radio tracking at G. Salak and Telaga Warna Nature Reserve, West Java was estimated between 310 and 930 ha. Conservation activities on the Javan Hawk-eagle have been conducted through organizing local training or workshop for awareness and community participation, nest protection programme and regular monitoring. Several local training and workshops have been carried out irregularly in West, Central and East Java. Nest protection programme with the involvement of local community has been successfully run mostly in West Java, e.g. at Cibulao Nature Reserve, G. Salak Protection Forest and G. Gede-Pangrango National Park. Regular monitoring has been practiced at Telaga Warna-Nature Reserve, Gede-Pangrango National Park and in certain area of G. Halimun-Salak National Park.
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ORIGINAL ARTICLES
  • Kazuto Kawakami, Hajime Suzuki, Kazuo Horikoshi, Hayato Chiba, Akira F ...
    Volume 5 (2006) Issue 2 Pages 187-191
    Released: February 01, 2007
    JOURNALS FREE ACCESS
    The foraging movements of six Black-footed Albatross Diomedea nigripes (an endangered species) breeding in the Mukojima Islands (a subset of the Bonin Islands) were successfully tracked over a period of two weeks using back-mounted global positioning system (GPS) data loggers (GDBL-II) during the nest-guarding period. Ninety percent of foraging was done over relatively shallow waters within 200 km of the breeding site. The population of this species in the Bonin Islands has not decreased during last ten years, while the area of long-line fishing is likely to overlap with the albatross foraging area around the islands. The effect on population should be assessed carefully.
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  • Sachiko Moriguchi, Tatsuya Amano, Katsumi Ushiyama, Go Fujita, Hiroyos ...
    Volume 5 (2006) Issue 2 Pages 193-198
    Released: February 01, 2007
    JOURNALS FREE ACCESS
    Abdominal profile index (API) is often used as an index of body condition in studies of anatids. However, few studies have statistically tested the relationship between API and body condition. In this study, we investigated the relationship between API and body condition of Greater White-fronted Geese Anser albifrons, taking into account the structural size effect on body condition. It was found that body mass, excluding the structural size effect, has a positive relationship with API. As API explained only 26% of the variance in body condition, we discuss the limitations of the method and the situations in which it can be used effectively.
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  • Yusuke Ueno, Masakazu Hori, Takashi Noda, Hiroshi Mukai
    Volume 5 (2006) Issue 2 Pages 199-209
    Released: February 01, 2007
    JOURNALS FREE ACCESS
    Piscivorous birds affect terrestrial ecosystems by transporting and introducing organic material and nutrients from aquatic systems. While most of these effects have been evaluated by simple comparisons of the abundance of terrestrial organisms within and outside colonies, little is known about the effects of nest density of piscivorous birds on rates of supply of material inputs within colonies, or on the abundance of terrestrial organisms consuming the materials. To clarify the effects of material inputs by the Grey Heron Ardea cinerea on necrophagous insects and understory plants in a forest, we evaluated the effects of nest density of herons on the spatial pattern of rates of supply of aquatic materials to the forest floor, and the response of necrophagous insects and understory plants to those supply. The herons transported aquatic secondary production in the form of chick carcasses and feces to the forest floor beneath their breeding colonies, and the supply rates were well explained by the nest density. Carcasses and feces increased the densities of necrophagous insects, but feces decreased the biomass of understory plants as supply rates increased. These findings suggest that to evaluate the effects of allochthonous inputs by piscivorous birds on terrestrial communities, it may be necessary to examine not only the presence or absence of bird colonies, but also to examine the relationship between nest density and terrestrial organisms.
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