Black Storks will be tracked on their way to Africa
Black Stork. Photo by Maris Strazds
This July eight female Black Storks were equipped with satellite transmitters to follow their travel to wintering areas in Africa and back. The aim of this study is to find out the causes of female mortality after fledging and identify the places where the Black Storks breeding in Latvia might have contracted poisoning with pesticides that have been found in the birds' eggs in recent years
Dr. Maris Strazds, the researcher of Black Storks, explains: "The latest studies show that the Black Stork population of Latvia is very close to critical state. In previous years many of the young storks fledged in poor condition, and females are the most affected. Possibly this is the reason why by the age of 100 days the proportion of females in population is only 20%, not approximately 50% as it should be. This leads to a higher proportion of single males that fight for females destroying some of the otherwise successful nests."
By now the only proved negative impact on the breeding success of Black Stork comes from forestry, but it is possible that one of the reasons for the poor condition of nestlings and high mortality of young females is poisoning with products of DDT decomposition, mainly DDE. This insecticide was banned from use in Europe in 1970s-1980s, but it is still used in Africa and Southeast Asia to combat malaria. It is possible that the Black Storks ingest DDT by catching fish in polluted rivers of Africa, but some of the data indicate sources of poisoning also in breeding areas. DDT or products of its decomposition have been found in all analysed Black Stork eggs since 2008.
Tracking of the Black Storks is part of project "Priority actions for Black Stork conservation in Latvia" carried out by Latvian Ornithological Society and funded by Latvian Environmental Protection Fund and Max Planck Institute for Ornithology. It will be possible to follow the movements of Black Storks in the website www.movebank.org. Project is also supported by TV channel "LNT".