Russian Cosmonaut Sergey Prokopyev released four research satellites into orbit and set up an antenna for tracking birds on Earth.
The space station is an ideal perch for the antenna, compared with a typical satellite, said project director Martin Wikelski of the Max Planck Institute for Ornithology in Germany.
The project will start out tracking blackbirds and turtle doves already outfitted with small GPS tags, then move on to other songbirds, fruit bats and bigger wildlife.
Mr Wikelski said researchers could better understand animal behaviour through lifelong monitoring.