There are currently about 10,000 species of birds existing in the world, however the mentioned number is not constant. It varies for two reasons: at first, scientists regularly discover new species; at second, some species regularly become extinct. The examples of birds extinction as a result of direct persecution is well known from the recent past. That was the reason of extermination of dodo, great auk, passenger pigeon and many other species (nearly 500 species during last 100 years). In response to that, a year after the last passenger pigeon has been killed, the first International Convention for the Protection of Birds was signed in Paris. In the industrial and postindustrial age the direct persecution is supplemented with reduction of birds’ natural habitats. In response to that the scientists and nature protection activists started a number of activities aimed at natural habitat conservation.