Factors Affecting the Distribution of Waterfowl Wintering in the Inland Water of the Saijo Basin in Western Japan.

Effects of human disturbances on the distribution of wintering waterfowl were studied in 64 irrigation ponds in the Saijo basin, western Japan, during 1998-99. Thirteen waterfowl species were recorded in 27 ponds. 100% of the waterfowl were distributed in ponds located in residential areas in 1998. Small number of the residential species, the Spot-billed Duck (Anas poecilorhyncha), used a single pond in forest in 1999. Waterfowl in residential ponds were regularly disturbed by natural and human disturbances except for hunting. Pedestrians, anglers and bird watchers caused the highest number of disturbances in both years. We suggest that waterfowl are capable of habituating to frequent and regular non hunting disturbances, which helped them to occupy the ponds in residential areas. Hunting was the most critical factor on the distribution of waterfowl in Saijo basin. Potential risk of shooting caused waterfowl to forgo using the ponds in forests. In addition to hunting, construction work and dry out of ponds caused waterfowl to abandon ponds.