The Kestrel, active by day, and the nocturnal Barn owl are two typical breeding bird species of the agricultural landscapes of the Swiss Rhine valley. They often find breeding sites in man-made structures such as farm buildings. The primary prey of both species are mice, and a Kestrel family may eat up to 20 mice a day.
During the past decades the population of Barn Owls and Kestrels has declined in Switzerland. In 2006, the association "Pro Riet Rheintal" started a recovery program for the two species, in close collaboration with the Swiss Ornithological Institute and local farmers. A working group was founded then and is composed of more than 20 farmers from the region as well as other interested persons.
Barn Owls and Kestrels breed in cavities and profit from artificial nest boxes. Accordingly the members of the working group selected many possible locations for new nest boxes. A group of farmers, led by Manfred Baumgartner from Kriessern, constructed the necessary nest boxes. Since then 120 new nest boxes were mounted in the project region between the villages of Diepoldsau and Oberriet. A yearly census of these nest boxes allows us to monitor population size, breeding success and the effectiveness of the recovery measures.
However, suitable breeding sites alone are of little assistance if adult birds fail to find sufficient food for their young. By implementing wildflower strips, meadows farmed at low intensity and hedges, we aim to increase the abundance of small sized mammals and large insects. Therefore, we educate farmers and motivate them to implement more ecological compensation plots where Barn Owls and Kestrels can hunt their major prey, mice.