Abstract—
Interspecific competition is an important mechanism of ecological community construction, which potentially contributes to resource differentiation and promotes the coexistence of sympatric species. Determining the food composition and resource differentiation of the whooper swans (Cygnus cygnus) and tundra swans (C. columbianus), can facilitate efforts to protect them. In this study, fecal microscopic analysis was conducted to analyze the feeding habits of whooper swans and tundra swans migrating to the Baotou Yellow River Wetland from February to May 2020; their food niche width and overlap were calculated, and the following results were obtained. The whooper swan’s diet consisted of nine species from four families of plants, mainly corn (Zea mays), reed (Phragmites australis), and halophytes (Suaeda glauca). The diet of the tundra swan comprised eleven species from five families of plants, mainly corn, quinoa (Chenopodium album) and millet (Panicum miliaceum). The food niche widths of the whooper swan and tundra swan in the Yellow River Wetland in Baotou were 2.75 and 5.18, respectively. There were five main species of food plants in total, and the index of niche overlap was 0.65. The food diversity of the tundra swan was greater than that of the whooper swan, indicating that the Yellow River wetland provides relatively diverse food resources for the tundra swans and whooper swans, thereby reducing competition and facilitating coexistence.
