I am a PhD student in the Chronobiology and Conservation Ecology group at the University of Groningen. My research focuses on avian sleep. One of the main questions I am trying to answer if birds have sleep homeostasis like mammals, i.e. if sleep is recovered by sleeping either deeper or longer after a period of sleep loss. Moreover, is the need for sleep during different ecological demanding periods (e.g. migration/breeding season) constant or variable?

The first studies of avian sleep have been done under controlled conditions, where we can clearly see what the effect of a certain period of sleep deprivation is. My aim is to extrapolate that knowledge to the field. Especially how certain ecological wake-promoting activities, such as migration, affect sleep. With small dataloggers, we can easily measure the brain activity of birds while they can freely move and interact with their conspecifics. With these techniques, we are able to understand how barnacle geese sleep under semi-natural conditions at the animal facility and how they respond to sleep deprivation of different durations across different seasons.

The ultimate goal is to see how barnacle geese sleep during the fall migration from Russia to the Netherlands. One of the main hypothesis is that birds, especially waterfowl, can cope with these wake-demanding periods by sleeping with one hemisphere, while the other remains more vigilant.

Sjoerd van Hasselt
Sjoerd with a newly tagged Barnacle Goose in Tobseda, Russia, August 2018. Photo: Götz Eichhorn