Influence of limited supply in artificial feeding on waterfowl in Lake Izunuma-Uchinuma

Abstract

The effect of decreasing artificial feeding on waterfowl was investigated in the artificial pond in Lake Izunuma-Uchinuma by comparing data between 2007/08 and 2008/09. The amount of monthly artificial feeding decreased 80% from 826kg to 42kg. Pintail Anas acuta, the most abundant species, and Whooper Swan Cygnus Cygnus decreased 79% and 74%, respectively. Moreover, the percentage (feeding/Field metabolic rate×100) of energetic dependence on artificial feeding by waterfowl declined 35-102% to 6-58%. Decrease of artificial feeding results in a more severe foraging situation for waterfowl.