Inferring the population parameters of the Broad-billed Roller Eurystomus orientalis and population stability in Kibi-chuo town, Okayama Prefecture

Abstract

We investigated population parameters of the Broad-billed Roller Eurystomus orientalis, including initial breeding age, breeding success, juvenile survival, and adult survival, in Kibi-chuo town, Okayama Prefecture, Japan from 2014 to 2016. The four parameters estimated were: initial breeding age at 2 years, annual breeding success was 3.5 chicks, juvenile survival was 22%, and adult survival was 68%. Consequently, the net reproductive rate was estimated to be 1.08. Previous studies have suggested high genetic diversity among populations of the Broad–billed Roller in Japan. During the study period, natal dispersal was observed between neighboring colonies, which could help promote their genetic diversity.