1) A study of breeding and dispersal of the black-billed magpie (Pica pica sericea) was made in the central (dense) and the peripheral (sparse) areas of its geographical range in Japan. Four aspects of ecological factors which may affect the geographical range were examined, i.e., population trend, nest-site characteristics, breeding ecology, and dispersal of young, between 1979 and 1984. The study areas were at the south of Saga City, Saga Prefecture (dense area), and at Kawatana Town, Nagasaki Prefecture (sparse area). The former was typical rural area with residential areas and croplands, and the latter was composed of croplands, orchards, woodlots and residential areas.

2) The density of nests was higher in residential areas (110.6±18.7/km²) than in the croplands (7.4±1.5/km²). This was attributed to the difference in the density of available nest sites. The magpies did not show any preference to the nest substrate, e.g., tree species, deciduous or evergreen trees, trees or utility poles. However, they selected trees 8 m or higher and utility poles for nest sites. Both tree height and nest height were higher in successful nests than in failed nests. It was suggested that the predation is one of the factors decreasing breeding success in low nests.

3) The magpies in the study area laid eggs from the end of February to the beginning of April (median, March 10). The eggs hatched from the middle of March to the end of April (median, April 1), and young birds fledged from the middle of April to the end of May (median, May 3). The fledging success, the proportion of nests at which at least one bird fledged, was 58.9% and 54.5%, and the brood size was 4.15±0.13SE and 3.75±0.43SE, in Area I and Area 2, respectively. The breeding success was equivalent in the central area and in the peripheral area.

4) The dispersal pattern of young magpies was similar in both the central and the peripheral areas of the distribution of the species. The young magpies dispersed gradually from their natal nests until autumn, and came back to near their natal areas by the first winter. The young tended to breed near their parents' territory.

5) The number of nests was increased in residential areas, probably due to a rich and stable food supply, and was relatively stable in the croplands during the study period. Similar tendency was recognized from the long term record of the abundance of magpie nests throughout Saga Prefecture in the literature. The magpie population is low in forest area, and is increasing where the proportion of forest area is decreasing. Annual survivorship of young birds after fledging was similar between the central and the peripheral areas, being 21% for juveniles and 59% for adults.

6) Short dispersal distance and breeding near parents' territory of young birds (natal philopatry) are considered to be major factors causing the small range of the black-billed magpie in Japan. The magpie range has been changed by recent deforestation and reclaim, which may cause the recent range extension in the magpie.

A population of Lithospermum erythrorhizon, a threatened plant in secondary grassland, was censused in a limestone grassland in northern Kyushu, Japan. Spatial distribution and size structure of the population were recorded. Plant species composition and vegetation structure in the habitat of L. erythrorhizon were also investigated. Annual control burning was conducive to establishment of L. erythrorhizon population, and limestone pinnacles affected the spatial distribution of the population. These two should be viewed as crucial factors in maintenance of L. erythrorhizon population in the study area.