On the basis of long-term researches (1968–2000) of reproduction of shorebirds and a waterfowl of Pribaikalye features of their nesting in conditions of a mountain – inundated water mode are considered. Its characteristic differences are brief, but high spring level waters and some summer flash floods (from 2 up to 7), sometimes looking like catastrophic flooding. Besides for many areas of Pribaikalye high number of ground and feathery predators, and also a high level of anthropogenous influences is characteristic. In result on the most productive watermarsh ecosystems it is marked very high (up to 70,0 % and more) loss of nests. In such conditions, a basis of maintenance of a necessary level of reproduction of coastal birds frequently is repeated (compensatory) their nesting. During too time, till now there are no techniques of allocation repeated clutches from total amount of nests. In this work features of allocation such clutches, controllable up to loss of a nest or hatch nestlings are considered. New methods of processing of the collected material, providing more correct calculation of success of reproduction of birds are offered.