The 98 km long Curonian Spit is a thin sand peninsula, ranging from about 400 m to 4 km in width, that separates the Baltic Sea from the shallow Curonian Lagoon. It has several settlements along its length. It lies on a major migration route for birds following the coastline of the eastern Baltic. Thienemann first visited the fishing village of Rossitten there in 1896 where he experienced “a bird migration proceeding in a regular manner but more massive than had ever before been observed in Germany” and he “could not stop wondering whether something of permanent value might somehow be achieved here”. At the German Ornithological Society's50th anniversary celebration in Leipzig in 1900 he gave a lecture that persuaded the Society to establish a bird observatory at Rossitten, as a cooperative project with the Prussian Government. Thienemann was given the job of setting it up, something accomplished when it opened on New Year's Day 1901, as well as serving as the founding director. The observatory operated under the auspices of the German Ornithological Society until 1923. From then until its dissolution in 1946 the observatory came under the management of the Kaiser Wilhelm Society, giving it a solid institutional framework. Its constitution was ambitious and broad, including nine main areas of bird research: migration, behaviour, moult, economic value, protection, the establishment of a bird collection, the procurement of research material for scientific state institutes, the expansion of research relevance to other kinds of animals, and public education. Heinrich Himmler sought to use storks bred in the Rossiten observatory to distribute German propaganda in 1943, an idea that was rejected successfully by Ernst Schüz. It was at first a one-man operation with Thienemann attempting to cover all areas of research. As it grew it focussed increasingly on the study of migration through banding, with roughly a million birds being banded during the 45 years of the observatory's existence. Its success stimulated the establishment of similar organisations such as the Hungarian Ornithological Centre in 1908, Heligoland Bird Observatory in 1910, Sempach Bird Observatory in 1924 and Hiddensee Ornithological Centre in 1936. Thienemann's successor as head of the observatory was Ernst Schüz.
Meanwhile, at Rossiten, now the renamed Russian settlement of Rybachy, the Rybachy Biological Station was founded in 1956, at the instigation of Russian ornithologist Lev Belopolsky, as a branch of the Zoological Institute of the Russian Academy of Sciences in Saint Petersburg. The station was set up following a special decision of the Board of the Academy of Sciences with the aim of studying bird migration, and of reestablishing the research tradition started by German ornithologists, after the ten-year hiatus. Viktor Dolnik was its director for 22 years, from 1967 until 1989. The station receives support from the Sielmann Foundation and works closely with western partners, including the Vogelwarte Radolfzell with which it operates a joint trapping and banding station.
