О статусе скопы в Грузии

Abstract

At present Osprey (Pandion haliaetus) is widespread and regular, but rare in small numbers passage visitor. Before the 1940’s it was a local breeder in small numbers at wetlands of the Black Sea coastlands, western part of Kolkheti Lowland and on wetlands in floodplains of some large rivers, and at large lakes in other regions of Georgia. Osprey extirpated as a regular breeder in the middle of 20th Century, no nests known since the late 1950’s. Last occupied nest was found in 1958 on Inkit Lake in Abkhazia. Analyzes of the historical data allows to suggest that before 1920’s osprey was widespread and regularly breeding species for some regions of Georgia. The most optimal conditions for breeding were in lower parts of large river valleys of the Black Sea basin – Rioni, Inguri, Chorokhi, Ajaristskali, Kintrishi, Supsa, Natanebi, Khobi, Gumista, Bzipi, Kelasuri, and large rivers of the Caspian Sea basin – Mtkvari (Kura) River and its tributaries. We do not have the precise data on the beginning of osprey disappearance in Georgia, it can be assumed that it happened in 1920–1930’s because of rapidly increasing human activity. In Georgia, where peculiarities of relief limit the possibility of some forms of human activity, coastal wetlands, flood-lands of rivers, large lakes (or the most preferred osprey breeding habitats), were transformed first. Large-scale reclamation work was carried out here, on the banks of the rivers and around large lakes, considerable massifs of floodplain forests were cut down. After the construction of hydroelectric power stations on some rivers, fish resources were reduced, and that undermined the food base for osprey. As a result of the powerful increase in human population, the level of the disturbance increased too. In the 1930’s mass raptor shooting campaigns were organized and lasted up to 1970’s. The use of DDT and some other heavy pollutants in the 1950–1960’s was also a major threat to the species. Prolonged and increasing effect of these threats led to the population decline – and later to complete disappearance of osprey in Georgia. Usually, osprey was recorded during migrations in Western Georgia, i.e. in the Black Sea basin: on the sea shore, coastal wetlands, wetlands of Kolkheti Lowland, in the lower parts of Rioni, Inguri, Chorokhi, Khobi, Bzypi, Kodori, Natanebi river valleys, on large lakes, fish-ponds, reservoirs, at sites with a regular supply of medium and large-sized fishes. Up to 95% of all ospreys observed from 1973 to 2023 were recorded in the Black Sea basin, mainly at seacoast, rarely on coastal wetlands. Much less often osprey was observed on alpine lakes of Javakheti Upland and on wetlands of Eastern Georgia, i.e. in the Caspian Sea basin. Vagrant individuals were recorded in very unusual habitats: in semi-deserts, in watershed areas at mountain ridges and on passes of the Great and Lesser Caucasus. In contrast to peculiarities of migration of majority of raptors, the osprey passage goes by wide front. This peculiarity explains the low number of ospreys recorded at permanent count-points on flyways and in bottlenecks in comparison with other raptors. The similar data were collected in Georgia – the average number of counted ospreys compiled in the average of 0.163–1.660 individuals/day, and their share in the total number of migratory raptors was quite insignificant. Spring passage takes place from mid-March through the early May, with a more-or-less visible peak in early April. First records of spring transients were on 7 March 1981, 19 March 1999 and 27 March 2015; last transients were observed on 28 April 1991, 30 April 2010, 1 May 1995, 16 May 2023 and 19 May 2017. About ⅔ of individuals observed in spring flown in the first half of April. Spring migration goes through quicker; birds rarely stay for several hours at sites suitable for feeding. The autumn migration has bigger intensity and lasts longer, autumn transit runs from mid-August to early November. Earliest transients were recorded on the Black Sea coast and coastal wetlands on August 14, 17, and 18, usually August 25–30. The latest transients typically were observed in late October, with solitary individuals recorded up to 2nd half of November on the Black Sea shore and coastal wetlands (19/11/1982; 21/11/1995). About ¾ of migrants were counted in second half of September – first half of October, with a soft visible peak in late September. From 300 to 500 individuals were considered to migrate per autumn season, mostly along the Black Sea shore. Typically solitary individuals were recorded, rarely pairs, never observed in flocks. However, in autumn birds, if they are not disturbed, can stay for several days at sites suitable for feeding. So, 2–3 ospreys simultaneously were watched in some halting sites on the Black Sea coastal wetlands.