 Pelicans have been persecuted by humans for their perceived competition for fish , despite the fact that their diet overlaps little with fish caught by people . Starting in the 1880s , American white pelicans were clubbed and shot , their eggs and young were deliberately destroyed , and their feeding and nesting sites were degraded by water management schemes and wetland drainage . Even in the 21st century , an increase in the population of American white pelicans in south @-@ eastern Idaho in the US was seen to threaten the recreational cutthroat trout fishery there , leading to official attempts to reduce pelican numbers through systematic harassment and culling . 
