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Description
In the past, several projects have been implemented to support the breeding of the Common tern in South Moravia, in particular the installation of wooden floating platforms and the care of natural islands in reservoirs. Our organisation has been systematically working on the protection of this species since 2008. The aim of this project is to prepare more technically suitable and resistant islands that will be more sustainable and safer. This will ensure even more effective protection not only of this animal species. In addition, as part of the innovation, floating islands with living vegetation will be created, which will create more suitable conditions for baby birds. At the same time, vegetation platforms will support nutrient reduction in highly eutrophic pond waters, create shelter for fish and provide alternative habitat for other species, they can serve as nesting habitat for other bird species. This is an innovation that has not been tested in practice before, making this project unique.
Summary of project results
The project focused on supporting and restoring nesting sites for the common tern (Sterna hirundo), a species classified as critically endangered under national nature conservation laws and as a priority species according to European legislation (Birds Directive). Our initiative involved installing specialized reinforced concrete floating islands that provide this species with alternative nesting habitats. These islands are designed to be sufficiently protected from semi-aquatic predators and to offer ideal nesting conditions.
Additionally, we combined these floating islands with floating vegetated islands, which support the biodiversity of aquatic environments. This innovative combination was tested in practice for the first time within our project, making it a unique approach. Through this method, we created a distinctive environment that contributes to the sustainable provision of nesting sites for the common tern and supports biodiversity in these areas.
Eight reinforced concrete nesting islands have been constructed. These islands are stable even in waves, resistant to vegetation growth, have a long lifespan, and require minimal maintenance. They are also designed to be safe from mammalian predators. All of these islands are complemented by vegetated floating islands, totaling an area of 56 square meters, which can act as platforms to catch fallen chicks.
Each of the reinforced concrete islands is equipped with three trail cameras that send several images of the colony each day. This setup allows us to monitor nesting activities in "real-time" and respond flexibly to potential risk situations (such as last year''s issues related to avian influenza). We can thus track the exact number of nesting pairs and chicks reared. The images and time-lapse videos are also used for project promotion.
In 2023, 251 pairs of Common Terns nested in South Moravia, with 82 of those pairs nesting on four new concrete floating islands. When we began protecting terns in South Moravia in 2008, there were only 57 breeding pairs. At that time, most of the pairs nested on unsuitable islands with low breeding success. Since then, the number of pairs of this endangered species has more than quadrupled compared to 2008.
The 2023 tern season in Central Europe was marked by the impact of avian flu. Over 170 dead terns were collected in South Moravia alone, leading to a decline in the number of breeding pairs at most sites—except for one. On one of the concrete islands, the numbers actually increased and were only marginally affected by avian influenza. This highlighted the importance of spreading conservation measures across multiple sites.
The nesting islands are safe and built for the long term. They were occupied in the very first year after being placed on the water. We expect they will continue to serve their purpose for decades to come, making a significant contribution to the viability of the tern population in South Moravia and, by extension, across Central Europe.