巣箱によるシジウカラの繁殖生態

抄録

The breeding ecology of the Japanese great tit (Parus major minor) was observed by use of nest boxes from 1961 to 1969. Three breeding habitats were used : a mixed wood of broad-leaved trees and pines, a dense pine wood and a sparse grass-land wood. The mean number of pairs per hectare in each habitat was 1.7,1.2 and 0.3. The nesting period ranged between 5 and 12 days, and its peak varied by year between late April and early May. The incubation period was 14 to 17 days and the nestling period differed from 12 to 17 days. There was no significant difference in clutch size between the years or between the habitats, the overall mean of clutch size was 8.9. There was also no significant difference in the brood size by the years and the habitats, the mean brood size was 6.9. The rates of homing in the adults were 0,16.6,20.0 and 27.3 percent, and those in the youngs were 0 and 7.1 percent. The longest homing record was four years in the adults. There were statistically positive correlations between the egglaying dates and warmth or sunshine sum.