Current state of colonial waterbirds on the Kaniv reservoir. - N.S. Atamas, S.A. Loparev. - Berkut. - 18 (1-2). 2009. - P. 1-15.
This work deals with estimation of current distribution of colonies and numbers of 12 colonial waterbirds species on the Kaniv reservoir (Dnieper, Ukraine) and changes in the number and species composition during the last 30 years. We have been investigating and finding the colonies regularly in 2006–2009 (May – September) and in 1976–2005 irregularly (July – August). Phalacrocorax carbo, Egretta alba and Larus cachinnans which have been expanding areals from southern regions of Ukraine began to nest and formed new large stationary colonies in the last 20 years. At this point in time 3, 1 and 3 colonies of those species are located respectively on the reservoir. Their numbers have increased gradually. The distribution of Larus cachinnans colonies changed a lot during 1989–1994 and at the end of 2000s. The numbers of native species of herons (Ardea cinerea, A. purpureа, Nycticorax nycticorax) have increased or been constant. Colonies of Larus minutus and L. canus, which had been located at the northern part of reservoir according to the literature (Klestov, Fesenko, 1990), are now extinct. The numbers of native birds, such as Chlidonias leucoptera and Larus ridibundus decreased considerably. A few pairs of Chlidonias leucoptera still nest at a single spot at the northern part of reservoir, yet the last colony of this species disappeared in 2005. It might be connected with extinction of water meadows, this species main nesting habitat, caused by development of building substantially. The distribution and numbers of the Larus ridibundus colonies changed significantly. A few colonies use the hydroengineering constructions as a nesting habitat in these times, instead of inundated islands and bogs at the northern part of the reservoir, unfit for nesting due to destruction and overgrowing with woody vegetation. There, the number of Larus ridibundus fluctuates considerably. The natural nesting habitat of Sterna hirundo and S. albifrons (the small sandy islands and spits) have been washed away completely. These species started nesting on the hydroengineering constructions, similarly to Larus ridibundus. Under such conditions the number of colonies has decreased slightly but the total number of nesting pair has increased. Conversely, for Chlidonias nigra, the number of colonies has increased from 3–4 in 1980s (Klestov, Fesenko, 1990) to 7 but the total number of nesting pairs has decreased considerably. According to the counts in 2000s, the maximal numbers of nesting pairs didn’t exceed 15. The number of colonies of Chlidonias hybrida have increased from 1 to 4 and the number of nesting pair – from 20 to 120 at the northern part of the reservoir in 2007–2009. It might be supported by Trapa natans which is the best nesting habitat for this species, expanding over the reservoir in recent years. The northern part of Kaniv reservoir between Kyiv and Plyuti and the central part between Kiylov and Rzhishchiv are the most important areas for conservation of colonial waterbirds at present. [Russian].
Key words: Ukraine, distribution, number, breeding, colony, habitat, conservation.
Address: N.S. Atamas, Schmalhausen Institute of Zoology, Bohdan Khmelnytsky str., 15, Kyiv 01601, Ukraine; e-mail: firstname.lastname@example.org.