Prey items delivered to young Northern Goshawks Accipiter gentilis by a single pair breeding in central Tokyo, Japan

抄録

We examined the diet of young Northern Goshawks Accipiter gentilis before and after fledging through the direct observation of prey items delivered by a single pair breeding in central Tokyo. Observations were conducted from 13 May to 14 August 2015. Three hundred prey items primarily belonging to five bird species and two genera of mammals were recorded both before and after fledging. The species contributing most to the total diet were White-cheeked Starling Spodiopsar cineraceus and Feral Pigeon Columba livia, with pigeons contributing most to total biomass followed by White-cheeked Starling. Prey item composition differed between the periods before and after fledging. After fledging, the contribution of White-cheeked Starling to the diet decreased, whereas that of pigeon increased.