birds. Autochthonous tree species include willow and poplar. By November 2017, the island has been populated with 5,850 seedlings of pedunculate oak, 1,000 of narrow-leafed ash, 1,755 of European white elm and 800 of black poplar. The last two are declared endangered species in Serbia. Also planted were 1,000 bald cypresses, which adapted nicely and began to reproduce. Fish A total of 53 species of fish were found in and around the island. Birds There are 66 bird species which actually nest on the island, 43 non-migratory and 23 migratory birds. In winter, during the nesting period, there are some 80 species present, while in the migration season, number rises to over 100. Some of the species are pygmy cormorant, black stork, mergansers, seven species of herons, over 40 species of ducks, and Icterine warbler. Altogether, 163 different bird species inhabited the island in the early 2010s, but by the 2020s, 208 species of birds were recorded, of which 200 were protected in some way. The island was the largest colony of the great egret on the entire course of the Danube, maybe the largest one in the Europe. During the NATO bombing of Serbia in 1999, the herons, for the most part, disappeared. Major attraction on the island is a pair of white-tailed eagles. A nesting couple, they settled on the island in 2010, migrating from the marshland of Pančevački Rit, across the Danube. They built a large nest, in diameter, at the height of . There are five other nesting couples in the wider Belgrade area, and some 90 in the entire Serbia, but having them reproducing at only from the downtown of a city of this size is an exceptional rarity. They reproduced for the first time three years later, in 2013. In April 2016, when their chicks were to be hatched, the city's communal services installed a camera in the nest. The project was unique, with the similar one in Estonia, but Belgrade is the only European capital to have it. Before the next generation of chicks hatched in 2017, live feed was posted online. The largest European eagles, with the wingspan up to , are best observed from the neighboring Ušće and Dorćol districts, but they are being spotted circling above the Kalemegdan and the Republic Square, practically the center of Belgrade. The couple was named Radovan and Ruža. In the summer of 2021, one