1) The Rufous Turtle Dove Streptopelia orientalis was studied in Kyoto, Japan and found to often re-use old nests for breeding. The hypothesis that the same breeding outcome (success or failure due to different causes) tended to occur at the same nest was examined with reference to the interval between two successive breedings.
2) Seasonal tendencies in breeding outcomes were not significantly different between new and old-reused nests. "Other failures" were most frequent in July to October, both at new and old-re-used nests.
3) "Other failures" occurred more frequently at the nests in which the preceding outcomes were also "other failures" within a certain breeding interval, but there was no such relationship for successful breedings. The tendency was diminished when all breedings were combined with no consideration of breeding interval.
4) The results obtained here suggested that nest predators tended to revisit previously preyed-upon nests within a certain interval. It is suggested that, as the risk of nest predation in using old nests could not be assessed by the present status of the nests, re-use of old nests involves an implicit cost of nest predation.

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1) Mating system of individually marked Japanese Bush Warblers Cettia diphone was studied at Myokokogen (36°52′N, 138°11′E, alt. 700m), central Japan, during the 1990-91 breeding seasons.
2) Territories were maintained for short periods. Although 35 territorial males were confirmed within a census area in a breeding season, only 10-14 (x=11.7, n=9) of them were observed on each survey.
3) Intrusions into territories by non-residential males were observed frequently. These intruders never sang there. In M98's territory, 15 intrusions by floating males and five intrusions by territorial males were observed.
4) In three territories, multiple females were observed breeding. In M98's territory, seven breeding attempts were made by 6 or 7 females within a season.
5) Females built nests and took the full share of parental care, including incubation, feeding nestlings, rearing fledglings, and mobbing predators.
6) Breeding failures, which might have been caused by predation, were observed frequently. There was a trend for females to leave a territory after one breeding attempt.
7) At least 21 females appeared in M98's territory, which suggests the presence of many potential mates for the male.
8) Home ranges of breeding females were much smaller than male territories. Female ranges seemed to be restricted to within male territories. The ranges of females nesting in the same territories overlapped. Agonistic behavior between them was not observed.
9) Singing activity of males was vigorous throughout the breeding season irrespective of the nesting stages of breeding females. No contacts between males and nesting females, including escorting behavior of females by males, were observed.
10) These results strongly suggested that the mating system of the Japanese Bush Warbler was advanced polygyny characterized by lack of pair-bonds.

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We examined the fruit species eaten by crows Corvus corone & C. macrorhynchos by analysing the faeces and probably regurgitated seeds collected at the pre-roosting sites in winter. Of the seeds identified, ca. 66% were seeds of dry fruits consisted of almost all the smacs Rhus spp. in the samples. The smacs include plenty of fat in the pulp. Its nutrition value seems very high under shortage of animal foods in winter. This is the reason why crows are especially fond of smacs.

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[in Japanese]

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[in Japanese]

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A total of 3, 000 to 3, 500 Carrion Crows Corvus corone and Jungle Crow C. macrorhycos was captured by "multi-traps" from 1987 to 1990 in Ikeda, eastern Hokkaido. Of trapped crows from July through December 1987, 564 Carrion Crows and 387 Jungle Crows were classified into two age classes, juveniles and adults, on the basis of the presence of bursa of Fabricius, tongue patterns and skull ossification. The percentage of juveniles (Carrion crow 82.4%, Jungle crow 97.2%) was always much higher than that of adults (Carrion crow 17.6%, Jungle crow 2.8%) and the total number of birds captured dependant largely on the number of juveniles in both species. The number of Crows captured decreased to less than 100 bird in May and June, and then increased to the peak of more than 600 birds in November and December. The probable reasons of the seasonal changes are the dispersion of young birds in July and food shortage from October or November.

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