Many people are interested in the question: are there many of these or other birds in the forest or field? This may not be just an idle interest. The number of birds is important for hunters, ornithologists, employees of specially protected natural areas. After all, only knowing the number of any bird species, it is possible to determine whether it is rare or not, whether this species needs to be protected or, conversely, its number exceeds the limits of the capacity of the land. With the help of surveys, we can understand what trends exist in the population of any bird species, and, probably, in the future, identify the factors that caused this or that change in numbers.