連続した降雨によるモズの巣内雛の死亡

抄録

In 2006 at Nobeyama plateau, Nagano Prefecture, central Japan, the death of most broods of the Bull-headed Shrike Lanius bucephalus occurred during a period consecutive rainfall. The rain lasted two and a half days from early morning on 17 July to noon on 19 July. Ten occupied nests were found before the rainfall, nine of which contained nestlings. In six nests containing only shrike nestlings, complete brood mortality was noted. However, in one nest with four shrike nestlings and in two nests with a cuckoo nestling the nestlings survived. The failed nests had two to six nestlings of three to eleven days old. Another four surviving nests had four shrike nestlings of three days old, one cuckoo nestling of 14 days old, one cuckoo nestling of about 15 days old, and five eggs, respectively. Of five eggs in the surviving nest, four eggs had hatched on 22 July, but one egg failed to hatch.