524 nests of 12 species of birds were examined in the Volga-Kama state reserve. From these nests there were collected 214575 mites belonging to 11 families and 48 species. The specific composition and quantitative ration between ecological groups of gamasid mites associated with the nests of birds depend not only on the evolutionary history of the host and gamasids-nidicols but also on many present factors, ecological type of the nesting place in particular.