A photographic analysis of the roost flock of Grey Starling

Abstract

On 29 November, 1963, excellent photographs of a big roost flock of Grey Starling were taken by Mr. Shigemoto Otaka at Koshigaya roost, Saitama Prefecture. Number of birds were counted by checking each bird within 2-5cm squares on the tracing papar attached on the photographs enlarged to 40×23cm. Even minute dots of birds could be checked with light from below. In a photo of distant flock estimates of densities per square were made by counts with sample squares. The results of counts from four (three show part of the flock) photographs well coincided and 15, 000 birds were determined for this roost in the early winter. Former observational counts were 49.690 birds in February and only 1, 500 birds in April, 1960.