There was a sharp decrease in the number and a reduction in the area of nesting of mute swan. Nesting places of mute swan at the end of the first half of the XX century are preserved only in the flooded areas of the lower reaches of the Dniester and Prut Rivers. After the ban of hunting and climate mitigation, alongside with a decrease in the number of severe winters, the population of this species has stabilized and then began to increase rapidly. For example, in the 80s of the 20th century, on the 200 hectares of flooded area, near the village of Antoneuca, Cantemir district, about 20 pairs of swans have made nests, and 2 pairs - on the lake of 10 hectares near Leova town. There are few main reasons of this phenomenon: adaptation to the man’s presence as a result of many years of prohibition of hunting and the increase in summer fodder resources as a result of eutrophication of water reservoirs. The above mentioned reasons combined with high fertility of species led to the observed increase in the number and appearance of new nesting places. At present, main groups of mute swan exists in the lower reaches of Dniester and Prut Rivers. Some pairs can be met on water reservoirs throughout Moldova. About 20-25% of the population starts with breeding. The main accumulations of immature and idle birds are found in the lower reaches of the Prut and Dniester (the lakes near the village of Manta, Slobozia Mare -3 thousand, on the Dniester - 0.6-1 thousand). In July, there is a redistribution of accumulations and an increase in the number of swans in connection with the movement of birds for molting. The main groups of molting swans are on the waters of reservoirs the lower reaches of Prut and Dniester. The main wintering grounds of mute swans in Moldova are located on the Dniester. During 2000-2016 the growth of the population from 0.5 to 6.5 thousand individuals were observed. Thus, according to O. Mantorov et al (2016) on the site NaslavceaCalaraseuca with the length of 24 kilometers 2567 individuals were observed and recorded in 2015, on the site Calaraaeuca- Ungur with the length of 8 kilometers was noted and taken into account 447 individuals mute swan, in the area of Oclanda – Unguri with the length of 27 kilometers -1332 individuals, in the area KremenchugKureshnitsa with the length of 18 kilometers - 2423 individuals. It is the most numerous wintering species at this sector in the middle Dniester. This species keeps in broods, with young birds, and large clusters on large shallow areas of the Dniester: Naslavcea, Verejeni, Mereseuka, Valcinet, Ocnita, Otaci, Unguri of Ocnita district, Rud-Arionesti tract in Donduseni and Soroca districts, Balintsy, Iarovo, Oclanda, Kremenchug, Holosnita, Kuresnita from Soroca district. The largest accumulations are observed near Kuresnita, Holosnita, Naslavcea, Verejeni, Mereseuka. It winters often with whooper swan, but the latter is inferior in number, and in addition, it keeps in the groups separated from mute swan. In winter swans sometimes die. It happened many times in severe winters in the waters of the Dniester and Prut. A considerable number of birds, mostly young, die every year. For example, in Western Europe about 50% of young birds perish, on the Azov-Black Sea wintering in Ukraine die from 10 to 85%. Overall growth in the number of mute swan is limited by the wintering capacity and it periodic death as a manifestation of the regular population processes. Population of mute swan in Moldova is characterized by significant fluctuation in the number in the result of birds’ death during wintering time and high reproductive potential (laying of 3-9 eggs, in average 5.8 eggs; broods of 1-9 chicks, in average 4.8 chicks). Moldovan part of mute swan population is characterized by a high nesting conservatism. Changing the nesting place of local groups is only possible in the case of significant changes in wetlands. Mute swan as a whole group of waterfowl has generally quite high adaptive capacity, in view of the high plasticity of the species. An important role in this is played by the favorable attitude of the population to this species. The study was performed within bilateral project between Moldova and Belarus.