White stork is one of the most known and popular birds in Ukraine. It nests almost all over the Ukraine, except south-eastern regions and most part of Crimea. The most birds are in the north-western region. Number of nests gradually decreases to the south and east.
Scientists point out 2 sub-species of white storks: European Ciconia ciconia ciconia Linnaeus, 1758 and Asiatic Ciconia ciconia asiatica Severtsov, 1873. In Ukraine it is possible to found only European sub-species. It spreads on the large part of Europe from the Iberian Peninsula to the Volga region and Transcaucasia. To the north, its natural habitat reaches Denmark, Southern Sweden, Estonia and North-Western Russia.
White stork started to spread around in the northern and eastern directions, appeared in Europe after the last continental glacier recession. Its expansion is still continuing, particularly at the east of Ukraine. In the XX century, population of white stork in Europe changed significantly. During a long period it depopulated and in many countries it was critically endangered. Population of white stork considerably decreased also in Ukraine. But near twenty years ago crucial changes has happened: population of white stork started to grow almost everywhere. But it is still less than it was in 1920–30th.
To know the state of population of one or another bird species and what changes could be expected as well as to implement actions on their protection, it is needed to observe changes of spreading, number of population and successfulness of breeding too. The best idea for this is carrying out of annual complex counts. Such counts of white stork nests are conducted in some European countries, for example in Germany, Czech Republic, Slovakia and Denmark. This method gives the more full and reliable data, but for Ukraine it is impossible to use it because of large territory, considerable number of white storks and lack of people, who are able to spend their free time to this work. That is why another way of study was chosen. It is a regular gathering of data from the network of set pilot areas. This monitoring gives more reliable data on the state of population than single counts, even if they would be complex and wide-ranging. They could distort general representation of data if they will include data of years with significant fluctuation of population not connected with longstanding trends.