Abstract
This paper details the identification of Rufous-tailed Robin, Dusky Warbler, and Radde's Warbler. These species were studied and captured by mist-net in Sakhalin Island, which is a breeding site of these three birds. Rufous-tailed Robin could be distinguished from female Japanese Robin by its smaller size, and from Siberian Blue Robin by its reddish brown tail. Measurements based on ca. 100 samples are presented (see Tables). Dusky and Radde's Warblers were very similar to each other, and lacked wing bars, which was common in the majority of Phylloscopus warblers. However, the former had a slimmer shaped bill and slimmer legs. Measurements of the two species based on ca. 20 juveniles are shown (see Tables). The average lengths of wings of juvenile Dusky and Radde's Warblers were 58.7 mm and 60.0 mm, respectively. Those of tarsus were 23.0 mm and 22.0 mm, respectively. However, the ranges were overlapping.
