We collated available evidence of breeding and conservation problems for the Japanese Murrelet in the Izu Islands, Japan. After species description in 1835, it was first collected in the Izu Islands ...in 1877, with breeding first noted in 1901. Over the 20th century, murrelets were found breeding at 11 islands (i. e., Udonejima, Niijima, Shikinejima, Hanshima, Kozushima, Onbasejima, Tadanaejima, Sanbondake, Motone, Kojine, and Torishima) and were not thought to breed at 7 islands (i. e., Oshima, Toshima, Jinaijima, Miyakejima, Mikurajima, Hachijojima, and Hachijokojima). Surveys have not been conducted at 7 islands (i. e., Zenisu, Inanbajima, Aogashima, Beyoneizu-Retsugan, Myojinsho, Sumisujima, and Sofugan). The population is centered in the northern Izu Islands between Udonejima and Sanbondake. Once considered the world stronghold for the species, a large population decline apparently occurred in the mid-late 20th century: a) breeding no longer occurs at Shikinejima and Kozushima; b) some breeding habitat has been lost at Sanbondake; c) large numbers of nests reported by egg harvesters at Udonejima, Hanshima, and Sanbondake in early century no longer occur; and d) murrelets were observed less frequently on ferry trips between Oshima and Niijima in 1990-95 than in 1983-89. Current breeding population size appears to range between 350-850 breeding pairs (-7-43% of the global population estimated between 4, 000-10, 000 birds or 2, 000-5, 000 pairs). Major colonies occur at Tadanaejima (100-300 pairs), Onbasejima (75-150 pairs), and Sanbondake (75-100 pairs), plus 20-30 pairs at Kojine. Another 100-300 pairs may nest at other islands (i. e., Udonejima, Niijima, Hanshima, and Torishima) where recent estimates are not available. Conservation issues include: human settlement; past egg harvesting; recreational surf fishing at remote islands; predation by introduced predators; habitat loss due to post-war bombing of Sanbondake; habitat destruction due to human activities; habitat loss due to volcanic eruptions; relatively high levels of predation by crows, snakes, and falcons; and mortality in commercial gill nets. Additional surveys, monitoring, and assessment of conservation issues are urgently needed in Izu Islands for this rarest species of the family Alcidae which is endemic to Japan.
The wintering distribution of Rooks Corvus frugilegus has expanded considerably in Japan since the early 1990s, but their migration routes and breeding sites have not been described. We ...satellite-tracked the migration of 20 Rooks from the wintering area of the Hachiro-gata polder, northern Honshu, Japan northwestwards in spring. The Rooks departed Oshima, Tsugaru, and the Shakotan Peninsula in northern Japan, and arrived in the Sanjiang Plain in northeastern China, and the area east of Blagoveshchensk in southern Russia, which are suspected of being their breeding areas.
The nest site characteristics of Northern Goshawk Accipiter gentilis, Grey-faced Buzzard Butastur indicus, Buzzard Buteo buteo and Honey Buzzard Pernis apivorus were studied in Tochigi and Nagano ...prefectures, central Japan. Regional differences were found in the nesting tree species used by goshawk; with Japanese Cedar Cryptomeria japonica used mainly in Tochigi and Japanese Red Pine Pinus densiflora used mainly in Nagano. Other raptors also nested in Japanese Red Pine. Goshawk nested on one of the largest trees in the forest, but there was no similar tendency in Grey-faced Buzzard. The specific characteristic of the forests where goshawk nested was that they had less tree coverage in lower tree layers than forests used by other raptor species.
Nesting locations of the Northern Goshawks (Accipiter gentilis) were investigated in two areas of about 390km2 in Tochigi prefecture, about 50km north of Tokyo. A total of 22 nesting locations were ...found in the area. Their food items were also monitored. A multiple regression model was constructed to predict the breeding density (measured as the total area covered by 1.8km buffers generated from the location of each nests within a 3x3km grid) from several environmental factors such as vegetation and human population size. The resulted model could explain about 63% of the variation in the breeding density (r2=0.63). Factors used in the model were: length of forest edge facing grassland (positive factor), area of bare land, construction sites etc. and human population size within each grid (negative factors). In this area, Goshawks were feeding mainly on small or medium sized birds, but the abundance, or biomass, of the birds was not an important factor that affected the breeding density of the Goshawks. The reason for this might be either that the food (amount of birds) is generally abundant in the area and therefore not an important limiting factor, or that availability of the suitable hunting area such as the forest edge facing the grassland is more important than the availability of the food itself.
We investigated the caching behaviour of Japanese Lesser Sparrowhawks Accipiter gularis during the breeding season in Tokyo and Utsunomiya, central Japan. Observations were made from April to July ...1987-1993 in Tokyo and 1991-1993 in Utsunomiya. A total of 46 caching behaviours were observed. All of the prey items cached were small and medium-sized birds, especially Tree Sparrows Passer montanus (65.2%, 30 of 46). Hawks cached prey that were half eaten by females, and prey which was not taken by the female in attempted prey exchanges initiated by the male. Many caches were carried out in the incubation and early nestling periods. Hawks stored prey on gnarled, broken twigs and leaf clumps on horizontal branches 7-8m in height and within a few meter to 50m apart from the food exchange site. Some birds used a few definite sites, and others used many places within a range of 50 × 30 m as caching sites. When hawks flew to caching sites with prey, they placed the prey carefully, and push it several times with their legs and beak. At least 11 stored items were retrieved within 3-247 min. (mean ±S.D., 78.5 min. ±73.2) after caching. Although 8 stored items were stolen by Azure-winged magpies Cyanopica cyana, most cached prey may be retrieved.
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