Branta Issues > Issue №2 (1999)

Causes of mortality in Cormorants breeding in the Azov-Black Sea region according to the ringing data

Pokusa R.V.

Data on the Cormorant (Phalacrocorax carbo sinensis L.) mortality and its causes in the local settlements on the North of the Azov-Sea coast during period from 1993 to 1999 are given. Recoveries of birds ringed as nestlings are analysed. Average duration of life made 1.75 years, with a maximum of 11 years. Juvenile mortality of birds originating from Obitochnaya spit made 68.5%. 64.4% of those from Molochnyi liman also die on the first year of life. Mortality decreases in the second year to 2.4-8.2% (table 1). Most Cormorants are killed by hunters (39.7%), a part gets into the fishing nets (11.6%), some die due to natural reasons (9.5%). For a large proportion of birds causes of mortality remain unknown (45.1%) (table 2). High mortality of birds on the first and second year of life due to the anthropogenic pressure prevents local population from a quick increase.