Mortality Counts of Short-tailed Shearwater Puffinus tenuirostris at Shiinauchihama of Kujukuri-beach, 1976-1982

Abstract

The mortality survey of Short-tailed Shearwater Puffinus tenuirostris along with Sooty Shearwater Puffinus griseus and Streaked Shearwater Calonectris leucomelas was carried out along 2km transect on Shiinauchihama beach in Chiba Prefecture in springs during 1976 and 1982. The peak mortality of Short-tailed Shearwater appeared from late May to early June every year. The dead bird density of Short-tailed Shearwater was low (12.3 ± 5.72(SD)/km, n=6) in 1976, and 1978-1982. Although a high mortality (44.5/km) occurred in 1977, it was due to an accidental local gale, while the mortality was extremely high (80/km) in 1974-1975. Therefore the countrywide mass mortality did not occur between 1976 and 1982. In the other two species, the mortality peak was not recognized and the mortality densities were lower than that of Short-tailed Shearwater through the period.