Branta Issues > Issue №3 (2000)

Number and distribution of marsh terns in the Ukrainian Danube Delta

Nesterenko M.A.

The article addresses distribution of marsh terns - the Black Tern (Chlidonias nigra L.) and the Whiskered Tern (Chlidonias hybrida Pall.) in the Ukrainian Danube Delta. Based on field surveys carried out in 1998-2000 and some published materials, breeding numbers of marsh terns in the area was estimated. Besides, the key breeding areas were identified (Kugurlui and Kartal Lakes) as well as the main factors influencing distribution of these two species. The Ukrainian Danube delta supports from 1500 to 2000 breeding pairs of Whiskered Tern depending on hydrological regime of the wetlands. Just a few pairs of Black Tern were found breeding in the area, that is indicative of the deficit of suitable habitats for the species. Both terns prefer mezotrophic lakes with abundant emerged aquatic vegetation, which are usual  for the secondary Danube Delta. These lakes were converted into artificial water reservoirs in the middle of the 60s and their current water management is the main factor influencing habitat structure and hence distribution and number of marsh terns in the Ukrainian part of the Danube Delta.