Swans sacrifice rest to defend their foraging areas

Images of swans typically bring up ideas of graceful, refined creatures. And although they possess these attributes, even swans have their rowdy days. 

New research conducted by the University of Exeter and the Wildfowl & Wetlands Trust (WWT) reveals that mute and whooper swans sacrifice resting to aggressively protect foraging areas. 

“These swans use aggression if there’s competition over foraging areas. Our findings show this this (sic) requires a trade-off, and that both species reduce resting time to allow for this aggression,” said Dr. Paul Rose.

“This was the strongest trade-off we found, but there was also a trade-off for both species between foraging and resting. However, there was no apparent trade-off between some behaviours, such as aggression and foraging, and aggression and maintenance.”

The trade-off can harm the swans since, without rest, the swans will burn precious calories and may not be as agile or aware of predators. 

Moreover, whooper swans are a migratory species, while mute swans stay in the same area throughout the year. Consequently, whooper swans are less likely than mute swans to change their aggressive behavior since they need to store fat before migrating.

The study, published in PLoS ONE, was conducted remotely, using a webcam. Dr. Rose says this data can inform conservation, habitat management, and future research.

“By providing enough foraging spots for the birds, we can reduce the need for aggression around desirable feeding spots, giving them more time to rest. This can help to ensure that migratory species don’t ‘push out’ non-migratory species when they mix in the same wintering locations. Our study also demonstrates how remotely collected data can be used to investigate fundamental questions in behavioural research,” explained Dr. Rose.

“At WWT we get lots of questions from our visitors about the aggressiveness of swans,” said Dr. Kevin Wood. “This new study helps us to understand how swans’ behaviour changes when they engage in their disputes.”

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By Erin Moody , Earth.com Staff Writer