Because Japanese cities have been developed for the purposes of pursuing only economy and industry, they are usually short of natural habitats, consisting mostly of nonorganic environments with few wildlife. Recently, however, it is strongly expected that new-styled cities with a variety of wildlife will be developed. In doing so, it is essential to know the ecology of wildlife, especially their habitat needs, and to apply that information to the city plan. In this paper, I review and discuss information concerning the relationships between terrestrial bird communities and the environmental factors of urban areas and, by using them, propose some methods for introducing and/or reintroducing those environmental factors needed to develop an "eco-city". The principal assertions are as follows: 1) Urban bird communities usually depend on vegetational factors such as amount, structure, species composition and dispersion of vegetation. Increase of vegetation volume may be most important for introducing a high diversity bird community into an urban area. An increase of green volume in an urban area could be promoted by adopting vegetation management by avoiding over-pruning, and a city plan that provides for increasing green space by aggregating houses (apartments, town houses, terrace houses), road systems with culs-de-sac, provision of underground car parks and the introduction of vegetation to walls and roofs. 2) The bird communities of "green islands" isolated in urban areas are usually affected by factors such as the shape, size and distance from adjacent green areas. Further, these relations may vary depending on localities, seasons and methodologies for analyses. Therefore, we need specific local surveys. For the present, Diamond's proposition (1975) will be effective as a guide, and the garden city with an extensive green area proposed by Howard (1902), could be considered as an ideal style of city favorable for inhabitation by a variety of birds. 3) Urbanized birds have the ability to use buildings as nestsites, and to use supports by man such as artificial feeding and nest boxes. However, since dependence on these man-made resources may benefit only a limited number of avian species, and possibly deprive natural resources from them, such supports should be avoided. From the same viewpoints, the introduction of exotic species should be prohibited since they may harm the bird communities and associated ecosystems natural to the areas.
The chemical characteristics of the surface soils affected by Sooty Shearwaters were investigated by analysis of 10 core samples taken from within each of three types of quadrats in three sampling areas on Motuara Island, South Island, New Zealand. These were (a) areas within 50cm of burrow entrances, but where leaf fall and trampling by the birds had been excluded (BURROW QUADRATS), (b) areas away from burrows and with normal leaf fall and plant cover present (LEAF LITTER PRESENT QUADRATS) and (c) areas similar to Leaf Litter Present Quadrats, but where all litter and plants had been removed at the beginning of the study (3 July, 1990) in cool, damp, calm conditions (LEAF LITTER ABSENT QUADRATS). Statistically significant differences were found between Burrow and other Quadrats, the former soil having lower pH values but higher electrical conductivity (EC) and phosphate levels. This suggests that the guano of Sooty Shearwaters lowers soil pH through the nitrification from ammonium to nitrate after mineralization of organic nitrogen, and enhances the EC and phosphate content in the surface layers. On the other hand, there was no significant difference in soil pH, EC, phosphate, potassium and total carbon and nitrogen content between Leaf Litter Present Quadrats and Leaf Litter Absent Quadrats, indicating that the absence of leaf litter and plants for a short period in winter does not significantly effect the chemical characteristics of the surface soils on Motuara Island.
A questionnaire on the distribution and breeding of the Black Woodpecker Dryocopus martius was given to 2, 086 persons in Hokkaido in 1987. A total of 1, 929 (92.5%) replies, including 2, 544 observations, were obtained. Of these replies, birds and nests were observed in 716 cases, calls were heard in 142 cases while there were no observations in 1, 060 cases. The number of adult birds counted ranged from 1 to 15 per observation site, and the cases of 1 or 2 bird sightings accounted for 90%. Although at most 4 adult birds were observed in a 5×4.6km quadrat (based on the known distance between neighboring nests), observations of more than 4 birds per quadrat were not reliable. The number of young (or nestlings) observed ranged from 1 to 4, and were within the range of known brood sizes. Breeding was observed in 47 quadrats out of 3, 652 quadrats in Hokkaido. Of those, 43 were in quadrats in which the vegetation was mainly coniferous and deciduous broad-leaved forests, and at altitudes lower than 500m. Black Woodpeckers were observed in 787 quadrats in the breeding season from March to August. Breeding was reported more frequently in coniferous, and deciduous broadleaved forests and mature larch plantations than from other types of vegetation. Including the observations during the non-breeding season from September to February, Black Woodpeckers were recorded in 958 quadrats. The main vegetation types of these quadrats were similar to quadrats recorded for the breeding season. Information about the breeding of the species obtained from the questionnaire is fairly reliable because most cases were based on the presence of young (or nestlings). However, the number of quadrats in which birds were observed were too high, especially at low altitudes, compared with the known distribution of the species in Tokachi district, eastern Hokkaido.
The wintering population of the Hooded Crane Grus monacha in Yashiro, Yamaguchi Prefecture, Japan, has declined from 250 to 41 individuals over the past 47 years. The cranes forage in harvested paddy fields during the daylight hours. Territories are defended by families in November and December and abandoned after January due to the decline in food supply. In January and February, cranes depend heavily on artificial food provisioning. During the nights, cranes communally roost on the top of terraced paddy fields, bare ground on hills, or ponds. When the temperature drops below 0°C, roosts on ponds are used frequently. Reduction of foraging areas, human disturbance and degradation of roosts are the major causes of the population decline. Conservation of the wintering area has recently been enhanced by the efforts of the municipal government, which has provided provisioning, rebuilt roosts and reduced human disturbance.
Thick-billed Murres, Uria lomvia, were obtained as an incidental catch during commercial gillnetting for Japan Sea greenling (Pleurogrammus azonus) off the Shakotan Peninsula, Hokkaido, in winter. Stomach content analysis revealed only Japanese sandlance, Ammodytes personatus (Pisces). In winter Japanese sandlance migrate to waters off the Shakotan Peninsula for spawning, where they are preyed upon by species such as Japan Sea greenling, masu salmon (Oncorhynchus masou) and walleye pollock (Theragra chalcogramma). It is apparent that the Thick-billed Murres compete with the above predatory fishes for the Japanese sandlance resource.