The effect of reed burning on Skylark Alauda arvensis density was examined during the breeding seasons of 2004, 2005 and 2011 in Watarase Marsh, an area of tall, dense reed bed associated with a large inland water impoundment (about 3300 ha) located in Tochigi Prefecture, central Japan. In this marsh, most of the reed bed is managed by annual prescribed burning conducted in mid-March. This study examined the response of Skylarks to the burning at two temporal scales (intra-annual and inter-annual), to assess the impact of prescribed burning on the breeding habitat of the lark. From mid-April to late July of 2004, the seasonal change in skylark densities along a census course were recorded during the regrowth period following a prescribed burn, and densities were compared to plant heights. Tall plants such as reed Phragmites australisand Japanese silver reed Miscanthus sacchariflorus grew gradually after burning, and these plants reached about 2.1 m in height at 100 days after burning. Skylark density showed a highly negative correlation with days after burning, i.e. the lark density peaked at about 40 days after the burning, when vegetation cover reached 0.6 m in height, and the lark density decreased immediately thereafter. There was, therefore, a significant negative relationship between Skylark density and the plant height. To assess the impact of prescribed burning on Skylark at an annual scale, this study recorded Skylark densities during an unexpected cancellation of the prescribed burning in 2011 due to a strong earthquake that occurred on 11 March. Data were compared to comparable results from 2004 and 2005. The density of Skylarks observed from mid-April to early May during the years with prescribed burning (2004, 2005) were significantly larger than that of the year when burning did not occur (2011). On the other hand, there were no significant changes in the lark density recorded along a bank with short vegetation cover (control site). In general, these results suggest that the prescribed burning of reeds in Watarase Marsh enhances breeding habitat for Skylarks. Repeated cancellation of burning, such as occurred in 2011, would restrict their habitat to such sites as road sides, banks and reed-harvest areas.

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The population of Eurasian Tree Sparrow Passer montanus has declined in Japan. The cause of the decline is considered to be a lack of suitable nest sites on residential and commercial buildings built more recently. When compared to older building styles, new construction lacks external cavities that can be utilized by sparrows as nesting sites, and therefore the reproductive rates have decreased due to a lack of nesting sites as newer construction replaces older structures. This study examines that effect by comparing the density of Eurasian Tree Sparrow nests observed in new residential areas to that of old residential areas. Paired study sites of residential areas with new and old construction were located in Iwate and Saitama Prefectures, Japan. In Iwate, the density of sparrow nests in the residential area built around 1980 was 3.8 times as high as that in the area built around 2000. Likewise, in Saitama, the nest density in the residential area built around 1960 was 4.8 times as high as that in the area built around 2000. These results demonstrate that the change in residential construction styles, which typically has well-sealed houses with few external cavities, plays an important role in the decline of the Eurasian Tree Sparrow population in Japan.

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The Grey Heron Ardea cinerea and the Great Egret A. alba are assumed to have competitive relationship for food resource because of their overlapped feeding habitats. We observed their feeding behaviours in rice paddy fields in central Honshu, Japan. The main diets of both species were pond snails Sinotaia quadrata histrica and weather loach Misgurnus anguillicaudatus, suggesting competition for foods between the herons. Although the frequencies of peck trials and successful pecks were higher in Great Egrets than in Grey Herons, food intake had a tendency to be greater in Grey Herons than in Great Egrets. This inverse result must be caused by the higher proportion of small pond snails in Great Egret diets. Great Egrets frequently peck and obtain smaller foods, and Grey Herons use infrequent chance to obtain larger foods, which may relax the competition in food between the species.

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A pair of Eurasian Wrynecks Jynx torquilla were observed breeding from June to July, 2012 in Hirosaki City of Aomori Prefecture, northern Japan. We recorded their feeding activity, using time-lapse photography (15 second interval), with a 300mm single-lens reflex camera. The auto-focus feature was not serviceable during low illumination or strong wind. Photographs were recorded from the hatching date on June 21, to the fledging date on July 13. During the latter brooding period, the number of photos showing feeding of the nestlings decreased. However, the number of photos showing warning behavior by Eurasian Wrynecks increased. The wrynecks were apparently wary of Chestnut-cheeked Starlings Sturnus philippensis, which are potential predators of wryneck chicks. During the first few days after hatching, the wryneck parents brought nestlings only ant cocoons, but after that initial period the adults also fed them adults and eggs of ants. The amount of food increased during the early and middle periods of the nestling phase, but then leveled off during the remainder of the nestling phase.

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I conducted the number of Great Cormorants Phalacrocorax carbo resting on artificial beaches at the Kasai Rinkai Park in Tokyo Bay from March 1996 to June 2012. Annual usage patterns were observed, including a rapid annual decrease in the number of cormorants using the rest site during February to March, and an annual increase of usage from June to September. The number of resting cormorants appeared to fluctuate according to their movements between roosting and foraging locations. During the winter season, the resting site at Kasai Rinkai Park is not along the route to the foraging site, but during the summer the cormorants pass over Kasai Rinkai Park along the route to the foraging sites. Counter to this general observed pattern of annual usage, the number of resting cormorants gradually decreased from July 2004, although the population of neighborhood colonies did not decrease. This suggests that the foraging site used by this population had changed from that of other years during the survey. Daily usage pattern at this resting site was also observed by conducting surveys during three periods each day, and the maximum number of cormorants monitored daily was generally recorded at noon. The roosting colonies associated with this resting site are located in areas with little potential disturbance that could restrict the cormorants time of return to the colonies. Therefore, it is possible for the resting cormorants to continue the return trip to the colony before the evening observation period.

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I investigated the characteristics of roofs that were used by Slaty-backed Gulls Larus schistisagus for nesting, and the positions of the nests on the roofs, in Haboro and Tomamae fishing ports along the Japan Sea coast of Northwest Hokkaido in June 2011 and 2012. A total of 23 nests were observed in 2011, and 27 nests in 2012. The gulls preferred flat roofs, or sloped roofs with snow guards attached, that ensure the stability of nest. The preferred nest position was roof edges. The edges appear to provide the nesting gulls the benefits of easy observation of the surrounding area and easy take off. Of the nests in 2012, 59% were located at the same positions of the same roofs as those of 2011. As a further study, to cope with the expected increase of conflict between gulls and humans, it is important to evaluate the habitat quality of roofs as breeding sites for gulls in coastal areas by investigating the breeding success rate of roof-nesting gulls, and then comparing breeding success with that found in natural sites such as Teuri Island.

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I recorded the caution behavior of Japanese Tits Parus minor.The tits sometimes give alarm calls against Oriental turtle doves Streptopelia orientalis probably because of the similarity of their flight form to that of a hawk. This behavior is thought to be a false recognition of tits that show their increased caution levels. I recorded the rate of this false recognition in the groves of Tokyo during late March to early May 2012 and 2013, and compared the difference of the rates between breeding (11 sites) and non breeding sites (17 sites) of Japanese Sparrowhawks Accipiter gularis.Japanese Tits frequency of alarm calls against Oriental turtle doves was significantly greater in the breeding sites of Japanese Sparrowhawks (61.0±12.5％，N=11) than in the non breeding sites (7.1±14.3％，N=17).It suggested that Japanese Tits tended to increase the caution levels in the breeding territories of predatory birds such as Japanese Sparrowhawks.

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During the breeding season of 2011, I conducted a study of the effects of stream noise on the song characteristics of Eurasian Wrens Troglodytes troglodytes. Four locations both sites with stream noise and those without noise in central Japan were selected. The sound level (dBV) of wren songs were higher at the sites with stream noise than the sites without stream noise. The sound level of wrens at the Aokigahara site, a site without stream noise was also relatively higher than the other non-stream sites. A possible cause of the higher level of sound in wren songs at Aokigahara was competition with biological noise made by cicadas Terpnosia nigricosta, which may have elicited the same effects on the wren songs as did stream noise. These results suggested that wrens sang more loudly to compete with the background noise. Furthermore, at the sites with stream noise, and at the Aokigahara site, the wrens sang a more simple song than in the sites without noise. Song complexity was represented by the number of modulations within a song, and the number of modulations per note of the song was lower at sites with stream noise. Also, the minimum frequency of the wren songs was higher at sites with stream noise than at sites without. This result is consistent with previous studies of bird songs in urban noise.

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