The behavior of crows (Corvus spp) at flight line assembly sites was observed in Takatsuki, Osaka, Japan, between December 1989 and March 1993, 1-3 times every 10 days. Three flight line assemblies were observed between daily activity centers and communal roost sites. Two species, Carrion Crow C. corone and Jungle Crow C. macrorhynchos congregated in these assemblies. Two hours before sunset I recorded the total number of crows and the proportion of juveniles at the assembly site. From two hours before sunset to 30 min after sunset, I recorded the number and the direction of each group passing over the assembly sites and the number of birds arriving at and departing from the assembly. The number participating in aerial evolutions and light intensity were also recorded. From every flight line assembly, almost all the crows flew to a single roost.Numbers of crows at the assembly two hours before sunset were positively correlated with the total number of crows arriving at the assembly after that each day, but were not correlated with the total number of crows passing over the assembly. Assemblies a and b were formed discontinuously during the winter. Assembly a was comprised mostly of juvenile crows and these birds departed earlier than the major groups of passing over. Assembly b was formed on a hilltop where crows roosted during autumn and spring. On several occasions, flight line assemblies became temporary roosting, just after or just before the crows changed the location of their roosts during the winter. Assembly c was formed continuously throughout the early summer at a site between the locations of an early-summer roost and a spring roost. The size of groups departing from assembly c increased just before the days when birds changed the locations of their roost and decreased quickly thereafter. Thus, patterns of seasonal usage varied among these flight line assemblies.

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I tested the usefulness of sound recordings compared with line transects for estimating bird species richness in a temperate broad-leaved forest. Many of the common species recorded by both methods showed similar and high occurrence rates (the percent of the number of line transect censuses or sound recordings in which a bird species was detected/total number of line transect censuses or sound recordings). And many species recorded only by one of the methods showed lower occurrence rates. The numbers of species detected by the sound recordings at fixed and random sites did not differ significantly.Relationships between the elapsed time and the cumulative numbers of species detected by each line transect census and sound recording showed that both methods yield a similar measure of species richness. The results of the present study indicate that sound recordings perform as well as line transect censuses for assessing bird species richness in a temperate broad-leaved forest.

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Sexual differences of Carrion Corvus corone orientalis and Jungle crows C. macrorhynchos japonensis were examined. Crows were captured by 'multi-trap' during April 1989 to June 1990 in Ikeda, eastern Hokkaido. Body mass, bill length, natural wing length, tail length, and tarsus length of carcasses were all measured. They were aged by tongue-markings and dissected in order to examine their reproductive organs. They were classified into two age-classes (adults and juveniles). Males were larger than females in all measurements for adults and juveniles of both species. Discriminant function analysis was carried out. The probability of correct discrimination of sexes for Carrion Crows was 87% for adults and 80% for juveniles. For Jungle Crows it was 91% for adults and 92% for juveniles. The sexes of both adult and juvenile Jungle Crows could be determined by discriminant function analysis.

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We collected a total of 296 pellets of Eastern Marsh Harriers Circus spilonotus from their winter roosts (two sites) in Watarase Marsh, Tochigi Prefecture between January 2002 and late February 2004. Out of these pellets 18 contained a total of 24 pieces of lead shot. Although most of the pellets (14) contained only one piece of shot, two pellets included two and three pieces of shot. Among the prey species found in the pellets along with lead shot, ducks accounted for 55.6%, and doves and crows 11.1%. A significantly higher frequency of lead shot in Marsh Harriers pellets was found in January and February, during the open season for game birds. Although lead poisoning is not yet known to have had any profound effect on the harriers using the study site, care must be taken to protect them from lead poisoning.

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