We investigated seed dispersal by wintering birds in an isolated urban green space in Tokyo. Seeds of nine plant species were found in the faeces of eight species of captured birds. The Brown-eared Bulbul Hypsipetes amaurotis, the Dusky Thrush Turdus naumanni and the Japanese White-eye Zosterops japonicus excreted 93% of the seeds, and these birds are dominant in the study site, suggesting that they are important seed dispersers. With the exception of one plant species, all the seeds found in the faeces of the captured birds were from plants growing in the study site, indicating that seeds were only rarely imported from outside of the green space. The faecal samples showed birds to have eaten fruits that were not only smaller but also larger than their gape width. Idesia polycarpa for example had fruits with diameters larger than, and not overlapping with, the gape width of the Red-flanked Bushrobin Tarsiger cyanurus, the Japanese White-eye and the Black-faced Bunting Emberiza spodocephala, indicating that birds can swallow fruits that are larger than their gapes. This finding may be caused by limitation of fruit-size selectivity of birds due to the small area of the isolated habitat and to the end of the fruit season.

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Golden Eagles Aquila chrysaetos typically inhabit environments with few trees, such as steppes or mountainous areas above the tree line. The Japanese Golden Eagle Aquila chrysaetos japonica, is an exception to this rule as it occurs in montane deciduous broadleaf forest. Seasonal changes in the spatial structure of deciduous broad-leaved trees may exert a considerable influence on the prey selection of the Japanese Golden Eagle, which may in turn influence its breeding success. In order to evaluate the effects of leafing on changes in feeding patterns and nestling growth of the Japanese Golden Eagle, we assessed the proportion of prey items taken, the delivery frequency and delivery amount to the nest by means of a video recording system. During spring and summer, Japanese Golden Eagles feed principally on Japanese Hares Lepus brachyurus and various species of snakes (Rhabdophis and Elaphe spp.); the total proportion of both prey items attained 98.3 percent (in frequency). Before leafing was terminated hares were delivered more frequently to the nest than snakes, but after leafing, more snakes than hares were delivered. The total amount of food tended to fall rapidly as this switch was made from hares to snakes. In nests where this change in feeding was noted, the total body length of chicks was smaller than in the nests of pairs that did not switch prey during the nestling period. When Japanese Golden Eagles change to specialized feeding on snakes as the leafing period advances, it seems that the reduction in food quantity affects the growth of their chicks.

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Mallard (Anas platyrhynchos), a surface-feeding dabbling duck species, has often wintered in the northern climate that freezes over most of their preferred habitats of shallow lakes, rivers and wetlands. A small wintering population was observed in mid winter at the entrance of Lake Mokoto, a brackish lagoon along the Sea of Okhotsk. They dived repeatedly to the bottom (1 m deep) of the lagoon and took benthic organisms. Their foraging success was high, averaging 78%. Most of their prey consisted of bivalves similar to or larger than their bill width (20 mm). They had a mean diving duration of 5.8±2.4 s SD (n=53), with a maximum of 12 seconds; and had a mean handling time to swallow their prey of 9.7±4.5 s SD (n=53), with a maximum of 21 seconds. The mean length of diving and handling bouts combined was 15.6±5.8 s SD, with a maximum of 31 seconds. Although theoretically they could have shortened these bouts by taking smaller bivalves, they tended to take larger bivalves that resulted in prolonged bouts, probably because more large bivalves remain given that the dominant Aythya diving ducks tend to take smaller bivalves during their stay at the same locality in autumn. Mallards were estimated to consume from 1.1 times to 3.5 times their body mass in bivalves in order to meet their daily energy requirements, when they selectively foraged on benthic bivalves. This range in amounts arises because of the varying quality of the bivalves. The northern brackish lagoon of Lake Mokoto, with its abundant benthic resources has played an important roll in supporting Mallards that have changed their foraging behavior in mid winter from surface dabbling for vegetation to diving for benthic bivalves.

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The breeding biology and habitat of the Black Paradise Flycatcher Terpsiphone atrocaudata were investigated at Kotorinomori, Fukushima Prefecture, Japan, in 2006 and 2007. Most of the pairs began building their nests at the beginning of June and all chicks had left their nests before the end of July. Most song areas were located within valleys, and were larger (average size; 4.25 ha) than those reported in previous studies (average size; 2.1 ha). Males and females shared incubation duration almost equally. Feeding frequency by the female tended to increase as the chicks grew. Most nests were built in live Magnolia hypoleuca trees. Tree density below the nest was low (average: 0.17 m²) whereas canopy coverage was 75% or more at all four nest sites that were surveyed. The relatively large spaces beneath the nest trees were because of a limited shrub layer. The nest sites tended to be located near roadsides or path sides, and near streams or wetlands. Among six failed nests, nest predation by crows was observed at one nest. Crows were also observed on or around three other nests on the days when the flycatcher parents stopped visiting their nests, indicating that crows may have a major impact on breeding success in this species.

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The relationships between natural elements, anthropogenic disturbances, and water bird species distribution were studied along a mid-stream section of the Abukuma River, northeastern Japan, in winter. Of the 17 bird species recorded in the study area, 14 were significantly affected by one or more items among the four explanatory variables in the multiple regression analysis. The distributions of Long-billed Plover Charadrius placidus and Little Egret Egretta garzetta were significantly correlated with the riffles. Conversely, Spot-billed Duck Anas poecilorhyncha distribution was significantly correlated with pools. Common Merganser Mergus merganser, Great Cormorant Phalacrocorax carbo and Mallard A. platyrhynchos were significantly correlated with river confluences. The distributions of Whooper Swan Cygnus cygnus, Tundra Swan C. columbianus, Northern Pintail A. acuta, Eurasian Wigeon A. penelope, Common Pochard Aythya ferina and Tufted Duck A. fuligula were significantly correlated with sites where people feeding birds. Grey Heron Ardea cinerea and Great Egret E. alba were significantly correlated with areas into which neither people nor vehicles intruded. Common Teal A. crecca showed no preference for any particular area. This study suggests that anthropogenic disturbances are critical factors affecting the distribution of water birds, and that preserving landscape elements composed of natural geographical features and vegetation are important for conserving biodiversity in river ecosystems from the standpoint of water bird communities in winter.

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