In the Kitakami Plateau of Iwate Prefecture, there is a population of about 30 pairs of Golden Eagle Aquila chrysaetos, however breeding success has been declining rapidly, with reduction in suitable feeding grounds implicated as a primary cause. Breeding success must be 0.282 or more to maintain the population. The area of feeding grounds required within home ranges (within a radius of 6.4 km) to achieve that breeding rate was calculated using a multiple regression equation. The area was calculated to be 560 ha for young (less than 10 years old) plantations alone, 1,020 ha for pastures/meadows and abandoned areas up to 5 years after cutting alone, and 770 ha for broad-leaved deciduous forests 101 or more years of age alone. Afforestation, at a 76-year interval, will be sufficient to supply the necessary young artificial forests for the eagles' home ranges. Line thinning was also considered effective in ensuring a sufficient supply of food resources and feeding grounds for A. chrysaetos. Furthermore, it is suggested that increases in biological diversity will result from cutting and thinning operations in plantations.

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This study examined the effects on bird assemblages of replacing deciduous broadleaf forest with larch Larix leptolepis plantations in the Chikuma Highland in Nagano Prefecture, Japan. Birds were sampled by the plot census method within deciduous forests and plantations in the winter and also during the breeding season. Sample sites were selected to cover a range of deciduous forest areas surrounding the study site. Redundancy analysis revealed that bird communities within deciduous forests were not associated with the loss of deciduous forests strongly in both seasons. Surprisingly, the occurrence of evergreen-conifer associated species decreased with the loss of deciduous forests, while canopy gleaners increased with the loss of deciduous forests. Hierarchical partitioning showed that the decrease of evergreen-conifer associates was actually caused by a reduction of hemlock and fir within deciduous forests rather than by loss of deciduous forest itself. Species that occurred less frequently within plantations tended to decrease as deciduous forests were lost. The results of this study suggest that the effects of deciduous forest loss on birds, resulting from the planting of larches, are weak unless loss of deciduous forest proceeds strongly. Species tending to decrease as deciduous forests are reduced may depend on resources eliminated during habitat replacement and habitat modification. Therefore, restoration of such resources in modified remnant habitats and the introduction of such resources into the matrix replacing original habitats may be effective in tempering and preventing species loss.

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We used radio-telemetry to estimate home ranges of adult male Northern Goshawks Accipiter gentilis during breeding (June–August: from nestling stage to postfledging stage) and nonbreeding (October–December) seasons in Tochigi Prefecture, central Japan. The average home-range size for 14 males during the breeding season was 1,052 ha calculated using the minimum convex polygon method and 899 ha calculated using the 95% fixed-kernel method. Breeding home ranges expanded significantly over the course of the breeding season. The distance between telemetry locations and nests increased significantly over several days for four of the 14 males. It is believed that, for these four males at least, a reduction in the frequency of feeding visits to fledglings in the late postfledging stage allowed the males to hunt in areas far from their nests, which in turn resulted in home-range expansion. The average home-range size of six males during the nonbreeding season was 2,609 ha calculated using the minimum convex polygon method and 1,678 ha calculated using the 95% fixed-kernel method. Although these males mainly used their breeding home ranges even in the nonbreeding season, they often flew long distances from their nests, leading to a 1.9-fold increase in their nonbreeding home ranges compared with their breeding home ranges. Both breeding and nonbreeding home ranges in the study area were smaller than home ranges reported in Europe and North America, with nonbreeding home ranges much smaller than those reported in Europe and North America compared to breeding home ranges. Because male Northern Goshawks mainly used their breeding home ranges year around, conservation of the breeding home ranges has high priority, but nonbreeding home ranges should also be managed for Northern Goshawk conservation if they contain important prey or hunting habitat in winter.

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In Japan, the abundance of Great Cormorants Phalacrocorax carbo disturbs sports fishing communities. Replacement of cormorant eggs with artificial eggs has been used as a method of decreasing the reproductive success of Great Cormorants. In this study, we evaluated the effects of egg replacement on the reproductive success and population abundance of a cormorant colony over three years. Both chicken eggs and artificial (gypsum) eggs were successfully accepted by cormorants. Although some pairs relaid after their eggs were replaced, the number of fledged chicks in nests with replacement eggs was lower than in nests without replacement. In 2006, relaid eggs were also replaced in 191 of 194 nests, resulting in only 12 chicks fledging. Therefore, replacement with artificial eggs was proven to be a very effective means of reducing the reproductive success of cormorants. Despite the recruitment of young birds into this population having been reduced experimentally, the colony has increased in size, perhaps because of the immigration of birds from other large colonies. Our results suggest that egg replacement can only reduce the numbers of new chicks, and the abundance of Great Cormorants within a colony may be influenced by the population size over a larger area. In the future, methods of egg replacement of Great Cormorants should aim not at population management, but at reduction of damage to fisheries by reducing the food intake of chicks during the breeding season.

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Nitrogen acquisition by Greater White-fronted and Bean geese from late autumn to early spring, was studied in Japan. Samples of food plants were collected from eight major locations throughout late autumn 2005 to early spring 2006, and analyzed for nitrogen content. Major food sources were waste rice grains, post-harvest soy beans and corn and secondary rice stems, together with several wild grasses and barley/wheat sprouts growing on rice fields. The nitrogen content of food species eaten by the geese just prior to spring migration was considered sufficiently high for their needs, being comparable to plant nitrogen contents documented from the Arctic breeding areas. The analysis indicates the potential importance of food source nitrogen as a criterion for site selection during migration and wintering. The importance for the geese of being able to eat foods with high nitrogen content following a long-distance migration is discussed on the basis of existing references.

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The influence of anglers on the feeding behavior of Greater Pied Kingfisher Ceryle lugubris was studied along the middle reaches of the Chikuma River, Honshu. Nests in Sakaki Town, Nagano Prefecture, around which the ayu fishing season began before fledging was completed, and in Nagano City, around which ayu fishing began after fledging, were compared in the breeding season of 2006. Feeding behavior near nests was recorded by automatic video camera. The location and number of anglers was also recorded around the Sakaki Town nest. Kingfisher feeding frequency tended to decrease as the activities of anglers increased, and prey size became smaller once the fishing season started. These results indicate that anglers near the nest disturb the Greater Pied Kingfisher's feeding behavior, and may negatively influence their breeding. To reduce such disturbance, it is preferable to restrict angling areas during the kingfisher's breeding season.

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