生態写真による大形カモメ4種幼鳥の識別

抄録

Based on 20 years observation made at Miyako, northern Honshiu, and over 1.000 photographs, the confusing young plumages of L. argentatus, L. schistisagus, L. glaucescens and L. hyperboreus were analysed comparatively. Chief points discussed are bill-shape, plumage pattern and general features which are shown in tables, figures and photographs. Although there are large individual and age variations in the markings and body size, the author could specify the species-specific patterns and the bill-shape was a good specific character.
A summary of molting of gulls is given by editor from Dwight (1925).