The Ural Owl is finally back in Vienna

45 pairs of owls are settled and breeding in the Vienna Woods Biosphere, contributing to a new population after the birds were considered extinct

Yesterday, the City of Vienna and the Vienna Woods (Wienerwald) Biosphere Reserve commemorated 10 years since the introduction of the Ural Owl back into the ecosystem. Out of the 140 birds released into the wild, there are 45 pairs happily living in Vienna Woods Biosphere Park and they have produced 26 young birds, making the project a success.

However, the Ural Owl is not out of the proverbial woods just yet, as 45 pairs is not a stable population, especially when climate change is factored in. Further efforts on boosting the species need to focus on the problem of genetic diversity, rather than just pure numbers.

Coming back again

Since the mid-20^th century owls had been considered extinct in Austria. The main cause of the extinction is considered to be the human killing of the birds. The situation was made even more unstable by the fact that owls lost their preferred habitats – mixed forests with large, old trees where they breed in hollowed trunks.

In 2009, scientists from the University of Veterinary Medicine in Vienna started a resettlement project and released the first owls in the Vienna Woods Biosphere Park and in the wilderness area of ​​Dürrenstein (Lower Austria).

Since then, 140 birds in total have been released in the Vienna Woods, and currently, 45 pairs are living there. The high concentration of birds in the area can be explained by the way the Vienna Woods are managed - compared to regular forests they have older and taller trees.

Despite positive numbers, scientists say the population is genetically still on a ‘shaky ground’. To make the owls resistant to diseases and climate change they need resilience. And according to a project manager at the Austrian Ornithologists Institute, the way to build resilience is through a certain level of genetic diversity.

This is why all future efforts will focus on releasing rarer genetic lines as opposed to a high number of birds. At the same time, the Viennese birds have made contact with the Czech-Bavarian and Slovenian colonies of the Ural Owl, further strengthening the population.

The project's end goal is to create a stable and continuous link in the owl population through the Austrian Alps, connecting colonies in Italy, Slovenia and Croatia with northern populations in Bavaria and Czechia.