Acta Zoologica Cracoviensia, 11() 1966
Nesting of Common and Black Terns
Abstract:
INTRODUCTION. On the basis of the data published by Sokołowski (1958) and Nowak (1965) most of the 9 species of terns nesting in Europe might be counted in the breeding avifauna of Poland. However, it seems that owing to the changes which have taken place in the distribution of some of these species in Europe within the last decades of years and against the general state of their present ranges, only 4 species nest within the boundaries of Poland. The Common Tern and the Black Tern nest comparatively frequently and numerously in suitable places, whereas the Little Tern is only rarely met with and no detailed data have been reported about the White-winged Tern in the recent years. The present paper deals with the structure of nests of the two most numerous species from among those mentioned above. Its principal objective is to find out the adaptive possibilities of both these species and, in spite of the great variation in the structure of nests associated with these very possibilities of adaptation, the distinctive characters of the nests of these two species such as will make it possible to distinguish these nests from each other and from other similar nests.
