Climate change causes late arrival
As days get shorter it is a signal to migrating birds that it is time to leave. At the same time the ongoing climate change causes problems for the birds when seasons change: Springtime comes earlier and Autumn stays longer.
In a theme issue of the scientific magazine Philosophical Transactions of the Royal Society B scientists pinpoint the wild clocks within animals. Susanne Åkesson, professor at the Department of Biology at Lund University, is involved in two review articles. In one of them she describes the problems that migrating birds face when temperatures rise. An example is the European pied flycatcher that breeds in central Europe. This bird seems to have problems to time its arrival and their nestlings need for protein with the time when there are most insects around.
The birds might arrive at a time which is not optimal because their internal clock can not be set to match the earlier arrival of Spring”, says Susanne Åkesson.
One important factor is selection. Selection favours the individuals that best adapt to changes in the world around them. Several studies have confirmed that individuals that migrate late will be late next time as well.
”There are differences between individuals and we believe they depend on when individuals are born. In general we find that it is better to be born early, the survival rate is higher, it probably also affect the time they migrate”, Susanne Åkesson says.
Another factor is the distance. Birds that migrate from sub-Sahara to breeding locations in northern Europe are limited in how early they can leave the wintering area. Plenty of food at the winter quarter, unfavourable wind direction and lack of food along the route may cause delays. This probably favours birds that do not migrate such vast distances.
Phil Trans B highlights the importance of closing the gap between chronobiology and ecology. The second review article Susanne Åkesson has contributed to describes different methods that can be used to study chronobiology in nature.
One example is the technique that is the result of the cooperation between CAnMove and Lund Laser Centre.
”We describe how the new tracking technology can be used to follow the movement of an animal in its natural environment as well as its circadian rhythm”.
The article about migrating birds and their biological clocks:
The article about different methods to study chronobiology in nature: