Researchers from the University of Exeter observed three species of swans: mute swans, whooper swans, and American swans, using video cameras over two winter seasons.
During the wintering period, besides swans, there were other waterfowl, and the cameras recorded all social interactions between them.
The researchers were primarily interested in conflicts and skirmishes — the goal was to determine which swans preferred to avoid each other. It turned out that they dislike each other the most: 80% of all conflicts occurred between birds of the same species (i.e., mute swans most often fought with other mute swans, whoopers with whoopers, and so on).
According to the authors of the study, this did not come as a surprise to them: among waterfowl, aggression within the species significantly exceeds interspecies aggression. This is likely due to the fact that for waterfowl, the most dangerous competitors are those belonging to the same species.
