Abstract
To facilitate conservation plans to protect a goose roost, we used a UAV to photograph water areas and roosting geese at Lake Izunuma-Uchinuma, where lotus plants have been spreading, in order to estimate the carrying capacity of the roost. No geese were observed to become alert during the descent of the UAV. Ninety-seven percent of 1,540 geese selected open water without lotus for roosting. Based on the mutual distance (1.2-1.3 m) between the geese and the number of geese roosting on the lake, the area of open water suitable for roosting was estimated at 13.3-18.9 ha, which amounted to 22.9-32.5% of the total area of open water without lotus on the lake.
