The Cuckoo - questions without answers. - N.N. Balatsky. - Berkut. 2. 1993. - P. 21-24.
There are about 80 main host species of the Cuckoo which nests it uses for laing eggs. The probable host species of the Cuckoo are considered and divided into main, supplemental and accidental ones. The Cuckoo lays 2-3 eggs in the nests of steppe and mountain host species, 3-5 eggs - for forest species, 3-7 eggs - for marshy species. The Cuckoo`s eggs do not change in size during coevolution in nests of hosts and consist about 3 % of female body mass. Cuckoo's biology has some peculiarities in populations of different ecological races and at different part of breeding range. [Russian].
Key words: Cuckoo, Cuculus canorus, nest parasite, host species, ecological race.