The wild population of the Japanese crested ibis (Nipponia nippon) was extinct in Japan in 1981. The reintroduction program of the ibis into natural environment started in Sado Island, Japan, from September 2008.

For the success of the reintroduction of the ibis, it is important to provide suitable foraging habitat. Their foraging habitat is known to be mainly paddy field. Although governmental agencies make an effort to create their foraging habitat, the effectiveness of these efforts are unclear yet. Their foraging speed (prey captures/min) in the paddy fields is currently monitored as a part of reintroduction program. Since caloric content of each prey varies depending on species and size of prey, it is necessary that we should evaluate not foraging speed but foraging efficiency (cal/min). To ensure the reintroduction of the ibis, we have to reveal the characteristics of the suitable foraging habitat. These data can be utilized to successfully manage their foraging habitat.

First, we recorded their foraging speed and measured environmental factors (e.g., food abundance, vegetation density, soil characteristics) for each foraging paddy. Second, we obtained the caloric contents of their possible prey and transformed foraging speed into foraging efficiency. Ultimately, we analyzed the effects of environmental factors on foraging efficiency of the ibis, by using GLMM.