Five Goshawks Accipiter gentilis fledglings were radio tracked to study habitat use and natal dispersal. Goshawks left the nest area about 40 days after fledging. There were three types of dispersal observed: sudden dispersal, gradual dispersal and stop-and-go dispersal (initial move about 10km from the nest site followed by another move). After fledging, the percentage of open habitat (e.g. fields and grass land) within their estimated home range gradually increased as they ranged more widely. Despite this habitat most used by fledglings was forests, and open habitats were avoided. The abundance of birds is significantly higher in open habitat than in forest area, and likely affected the result because fledgling Goshawks preferred to hunt from groves of trees located in open areas.

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A supply of roost and foraging sites are essential factors for migratory waterfowl to survive the wintering season. Severe weather, including the freezing over of lakes (used for roosts) and heavy snow cover on fields (reducing foraging efficiency), is generally considered an important factor deterring waterfowl from wintering further north than Miyagi Prefecture. In 2005/06 winter season, severe cold air masses often migrated to Japan and caused prolonged periods of frozen lake roost sites, and heavy snowfall in the foraging area. To study the relationship of severe cold air masses to fluctuation of the wintering waterfowl population, we compared data for average air temperature and snowfall, with the number of waterfowl wintering around Lake Izunuma-Uchinuma, northern Japan, from November to January between 2005/06 (severe winter) and 2004/05 (normal winter). In 2005/06 winter, there were especially low air temperatures and an increase of snowfall in December; as a result, the period that the lakes were frozen was prolonged three times that of the previous winter. The total number of waterfowl remained stable throughout the winter of 2004/05. During the severe winter of 2005/06, however, the number of Whooper Swan Cygnus cygnus increased, and ducks increased earlier than during the 2004/05 winter. In contrast, the population of Greater White-fronted Goose Anser albifrons was stable. The increase of Whooper Swan, and early increase of ducks, might be ascribed to an increased population from flocks moving from northern areas to this southern refuge due to severe conditions. The stability in the number of geese is likely due to the fact that most geese in northern Japan already congregate for winter around Lake Izunuma-Uchinuma; therefore, no new flocks would emigrate from northern areas to Lakes Izunuma-Uchinuma.

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In the winter of 2006, a mass mortality of Tree Sparrows Passer montanus was reported in central Hokkaido, mostly from citizens with bird feeders. We compared the seasonal change in sparrow density, from route-census surveys on the Hokkaido University Campus, during a normal period (2003-2004), and during the period which included the mass mortality event (2005-2006), in order to evaluate the density change in the sparrow population in Sapporo. The fluctuation of sparrow density in the 2003-2004 period was small. However, a sharp drop in density was documented between December 2005 and January 2006. The timing of the population crash synchronized with the start of citizens' inquiries. It suggests the importance of the citizen's role as population monitor of common birds such as Tree Sparrows. Since Japan lacks an emergency response system for a wildlife crisis, it is essential that a nation-wide monitoring system of wildlife health be established, and people in the related fields (e.g. government officials, NGO's, and research scientists) share information to maximize observations from citizens recognizing an ecosystem crisis.

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The decrease of flying insects may be one causative factor in the observed decrease of summer resident birds in Japan, however, the author is unaware of any studies on insect abundance that addresses this potential relationship. Therefore, a pilot study to evaluate a convenient method to monitor flying insects was conducted in west-central Tokyo. The numbers of flying insects on the lighted panels of soft drink vending machines, located in several typical outdoor environments, were counted at night from April to August in 2005-2006. During April to June, the abundance of insects was greater along the river than in other areas, while the difference was smaller during July to August in both 2005 and 2006. The patterns of seasonal changes in the abundance of insects were similar between 2005 and 2006. The arrival periods of Barn Swallows Hirundo rustica at nest sites in two locales appears to correspond with the observed pattern of insect abundance. The majority of swallows nesting along river sites arrived earlier than those at other locations, possibly to correspond with the early peak in insect abundance that was recorded at the river sites. These results suggest that counts of insect abundance at lighted vending machines can be an adequate method of monitoring the relative abundance of flying insects as a food resource for birds. Further investigation and refinement would enhance the value of this convenient technique.

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The breeding abundances and habitats of Water Rails Rallus aquaticus and Ruddy Crakes Porzana fusca were surveyed from mid May to late August of 2005, and mid April to late August of 2006 in the Watarase Marsh, central Japan. Presence of the birds was confirmed by response to species-specific calls broadcast from a handheld cassette player. Twenty out of 110 survey sites in 2005, and 16 out of 140 survey sites in 2006 were confirmed to be occupied by Water Rails. The number of sites occupied by Ruddy Crakes were limited to two sites during each of the two survey years. The abundances of these species were estimated to be 12 in 2005 and 10 in 2006 for Water Rails, and one each in 2005 and 2006 for Ruddy Crakes. The habitat type where the rails and crakes were confirmed present during the survey was wet reed with dense undergrowth, such as Carex spp. in standing water less than about 20cm in depth. No response was recorded at dry sites with dense tall vegetation lacking undergrowth. The restricted distributions of these two breeding wetland species in the Watarase Marsh may be related to an apparent decrease in the wettest habitat types. I recommend the restoration of wet habitat at Watarase Marsh. Management techniques such as scouring the reed floor may result in an increase of suitable habitat for wetland birds such as the rails.

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Three colonies of Great Cormorants Phalacrocorax carbo were surveyed in Tokyo Bay in order to estimate the number of fledglings per nest. Chicks over three weeks of age were considered to be fledglings, and the nest was classified as successful. The number of these chicks per nest was recorded at each colony. We compared the results with similar data collected during each breeding season between 1999 and 2004. Breeding success of each colony was found to fluctuate annually, and some significant differences in fledglings per nest were found between some colonies during some years.

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Observing bird nests by use of video cameras is a frequently used method to study breeding ecology of birds. Despite its versatility, this method demands a great amount of time and trouble for a human reviewer to extract the relevant information from these video data. We tested the utility of a motion detecting software "UFO Capture V2" applied to video data in which parent birds delivered food to their nests. Using this software, we captured video clips of the birds' feeding behavior and compared them to data that had already been recorded by a human observer. As a result, we succeeded in detecting all the feedings, though non-feeding movements were inevitably captured. This software would be an effective tool to assist the analysis of video data, because a human reviewer would only need to review the portions of the recordings that were identified by the software in order to exclude the non-feeding movements.

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