I am a researcher with a wide interest in behavioural ecology, and I am strongly fascinated in animals’ capabilities that sometimes are to obscure to even imagine for us humans.  I think that one of the most remarkable phenomena in nature is animal migration and how billions and billions of individuals are able to cross continents and oceans during their annual journeys. A migratory songbird, weighing about 15-30 grams, fully exposed to weather and wind, traveling alone by night and possibly even for the first time. How do this individual manage to cross continents and find its way back and forth to its wintering grounds? I think that this is a fantastic and very inspiring question.

My research aims to elucidate how individual birds manage their migrations, how their behavioural adaptations facilitate the extreme travels conducted by birds, and how limitations to flight might affect their ability to travel in a changing world. To study migratory behaviours, I mostly work with different types of tracking that makes it possible to record movements and behaviour of birds both at a site and throughout the full annual cycle. I mainly work with songbirds, such as the great reed warblers breeding in Lake Kvismaren, central Sweden. However, I am also part of e.g. the project studying the migration of great snipes Jämtland in northern Sweden.

I did my undergraduate studies at Stockholm University before starting my PhD in Lund in 2009. I defended my thesis “Stopover behaviour in migratory songbirds: orientation, timing and departures” in 2015, before moving to University of Copenhagen for two independent postdoc projects on individual behaviour in migratory birds throughout the full migratory cycle and the effects ecological barriers have on these behaviours. I am back at Lund University since 2021 as an independent researcher.

Research highlights

In two papers in Science and Current Biology in 2021, I, together with colleagues, showed that both great reed warblers and great snipes migrate at unexpectedly high altitudes during diurnal flights The birds ascended from relatively high flight altitudes at night (2-3000m) to extremely high cruising altitudes at day (4-8000m). This novel diel cycle in flight altitudes can not be explained by night and day differences in wind directions or high air temperature, but could potentially be a behavioural reaction to avoid overheating caused by solar radiation when flying at daytime.

Sissel Sjöberg, Gintaras Malmiga, Andreas Nord, Arne Andersson, Johan Bäckman, Maja Tarka, Mikkel Willemoes, Kasper Thorup, Bengt Hansson, Thomas Alerstam & Dennis Hasselquist (2021). Extreme altitudes during diurnal flights in a nocturnal songbird migrant. Science 372: 646-648.

Åke Lindström, Thomas Alerstam, Arne Andersson, Johan Bäckman, Peter Bahlenberg, Roeland Bom, Robert Ekblom, Raymond Klaassen, Michail Korniluk, Sissel Sjöberg & Julia Weber (2021). Extreme altitude changes between night and day during marathon flights of great snipes. Curr. Biol. 31, 3433-3439.e3