Transmitters Fitted to Golden Eagles Show Effects of Wind Power Exploitation

The researchers will visit five territories of the golden eagle located in two counties, Västerbotten and Västernorrland. An experienced bird ringer will climb up to the nests and fetch the juvenile birds.

“We will both ring the juvenile eagle and fit it with a satellite transmitter. While it is not uncommon to ring juveniles of the golden eagle, this is the first time the birds are brought down from their nest and fitted with a transmitter,” said Tim Hipkiss at the Department of Wildlife, Fish and Environmental Studies, who is running the project*.

The birds are just two months old and have not left their nest yet. Still, they are big enough to have the backpack-resembling satellite transmitter attached to them, by the researchers.

The entire transmitter installation procedure, that is to fetch the bird, attach a transmitter to it and then climb back up to the nest with the bird, takes about half an hour.

“We take the opportunity when the parents are not around. It is exciting enough to climb ten meters up a pine tree to fetch an angry juvenile bird,” said Tim Hipkiss.

The transmitters reveal the movements of the juvenile birds

In some of the territories that the researchers will visit, wind farms are planned. With the help of the satellite transmitters, the researchers can follow the movements of the birds, before and after wind power exploitation. Using satellite telemetry, the position of each bird is transmitted several times an hour.

“Hopefully, we will be able to identify the preferred habitats of the golden eagle. Once we have done that, we can recommend where to build wind turbines and wind farms in the future, without disturbing the golden eagle, and where to avoid wind power exploitation,” said Tim Hipkiss.

This autumn, the researchers will catch and fit adult golden eagles with satellite transmitters. The adult birds will carry their transmitter for five years, while the juveniles will only carry theirs for two years.

*The aim of the project “Effects of wind power exploitation on habit choice and reproductive success of the golden eagle” is to understand the effects of wind power exploitation on habitat and landscape use of the golden eagle, and its presence and reproductive success in the northern forests of Sweden.
The results will lead to recommendations on how to exploit wind power, taking into consideration the requirements of the golden eagle. The project is financed by the Swedish Environmental Protection Agency, the Swedish Energy Agency and the energy companies Vattenfall and Statkraft.

By fitting juvenile birds of the golden eagle with a satellite transmitter, researchers at the Swedish University of Agricultural Sciences hope to learn more about how wind power exploitation affects the birds. The golden eagle (Aquila chrysaetos) is classified as near threatened in Sweden. Photo: Tim Hipkiss/SLU