Abstract
An observational study of loafing and sleeping behaviour of Trumpeter Swans was conducted in southern Ontario throughout the year in 2018 and 2019. Like other birds, these swans have the ability to close down one brain hemisphere at a time during rest, which is indicated by eye closure. We quantified rates of closure of eyes during sleeping bouts for both breeding and non-breeding swans. Single eye closure varied in frequency, duration and in terms of which hemisphere was shut down. Increasing duration of eye closure over time indicated an increased sense of security with surrounding in one mated pair. Proportion of time with both eyes closed during sleep differed significantly between breeding and non-breeding swans, which may reflect security related to social status. Unlike ducks, which "peek" during sleeping, Trumpeters raised their head briefly during sleep bouts, likely in response to auditory stimuli. Both “peeking” (precautionary vigilance) and “head up” behaviour (reactionary vigilance) are adaptations to predation risk. There is much still to be learned about sleep behaviour in swans and other birds.
Creative Commons License
Recommended Citation
Lumsden, Harry G.; Markhoff, Gerry; Lane, Gary; and Scott, Allan
(2020)
"Loafing and Sleeping Behaviour of Trumpeter Swans,"
Ontario Birds: Vol. 38
:
Iss.
3
, Article 9.
Available at:
https://digitalcommons.usf.edu/ontario_birds/vol38/iss3/9