International Association for Danube Research the Danube. In a more recent branch of IAD in Austria, the ÖK (Österreichisches Komitee), scientists with outstanding research related to the Danube Basin in Austria are awarded with the “Liepolt-Preis”. The major achievement in the first decade of IAD was the monograph “Limnologie der Donau” (Limnology of the Danube), edited by Liepolt and published by E. Schweizerbart’sche Verlagsbuchhandlung (Nägele & Obermiller) Stuttgart in 1967. In the same year, the Commission for Hydrology of the Romanian Academy published the monography “Limnology of the Romanian sector of the Danube”. In 1986, S. Godeanu and V. Popescu-Marinescu released the bibliography “Limnologie der
Birds of the Danube Delta and mixed form of colonial nesting. Such an observation and interpretation of the colonial nesting origin in the Danube Delta may constitute an argument for properly explaining the colonial nesting phenomenon in different regions or the globe. Birds of the Danube Delta Following an almost two-decade (1951–1970) research of the Danube Delta territory, 274 bird species were identified of which 176 were brooding (sedentary and migratory) and 98 non-brooding ones (winter, passage, erratic, and accidental birds). The species of brooding birds occurring in the Danube Delta were classified into 12 main biotopes, the classification criterion being represented by the nesting