Abstract
Seven Little Tern Sterna albiformes colonies, long known to local birders, were investigated in 1993 and 1994. The colonies were all small, ranging from a dozen to about 100 individuals. All but one of the colonies were located on spits formed in middle reaches of the Tone River, in Gunma Prefecture, central Honshu. These colonies all suffer from degraded environment (heavy weed growth) and frequent disturbance from human activities (the area is a popular sweetfish fishing spot), and as a result, colonies are small and reproductive success is low. 32 birds were banded and color ringed in 1993, and 18 in 1994. Also, Common Tern nesting activity was confirmed at the reach site C in 1993. This report, along with Yamamoto (this volume) represent the first breeding records for Common Tern in Japan.
