In the river Rhine, islands can no longer be created due to the permanently strong current. They would also pose a threat to shipping. In the lakes in gravel pits islands was partially created. At first we thought that these would be more suitable for common terns, as they are bigger. Then we realized that on the islands grows bushes and trees after a few years. This vegetation can only be kept away by a very intensive annual care.
But such islands are also attractive to other bird species. On the Lower Rhine area, seagulls settle on such islands. Since Lesser Black-backed Gulls, Yellow-legged Gulls and Herring Gulls also eat eggs and chicks of Common Terns, there is no coexistence. The terns then leave the islands.