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Tiny satellite transmitters reveal peculiarities of the life of the rare Lesser Kestrels
Following the location coordinates sent by the transmitters, our team reached Greece, where one of the Lesser Kestrels was getting ready for the autumn migration.
5 grams! This is exactly the weight of the device used by Green Balkans for tagging and tracking Lesser Kestrels within “Lesser Kestrel Recovery” project funded by the LIFE program of the European Union. This is done to find out various peculiarities of the life of the Lesser Kestrels from the newly established colony, such as migration routes, roosting sites, wintering grounds, etc. So far, the Lesser Kestrels are the smallest birds tagged with this type of transmitters in Bulgaria. This tiny satellite transmitter corresponds to the size and weight of the graceful falcons, so that it does not put any burden on the birds and at the same time provides enough data about their movements. Through this transmitter and the satellite system Argos, the location of each tagged bird is visualized on a special server, so that the team can easily use the information.  
Well, it didn’t take long before we received the first curious data! Two of the tagged Lesser Kestrels - BSB and BDS (named after the codes on their color rings) showed their hunting grounds and the areas where they were getting ready for their autumn migration. These are females that this year raised offspring in the newly established colony in the village of Levka, Sakar SPA. Having raised their chicks, both females demonstrated totally different behavior. BDS, which in 2014 bred in Sakar, stayed in the area of the colony, and together with 30-40 Lesser Kestrels roosted near its recent nesting site. Thus, the team managed to locate the roosting site and count the roosting birds on a regular basis, collect food remains, and make observations of the birds’ behavior.
The behavior of BSB was even more curious. It is younger, breeding for the first time in 2015. Right after the end of the breeding period, BSB left the colony and headed southwards, to Greece. There, the bird settled in the Pangaion Hills, near the town of Kavala. So, late last week, Green Balkans’ team implemented an expedition to the Greek mountain to survey the bird’s habitats, examine the region for presence of other individuals from the colony in Sakar, and check if the tagged bird had joined groups of birds from other colonies. It was found out that BSB and some 10 more Lesser Kestrels with no rings inhabited a small valley of mosaic agricultural plots. Owing to the data sent by the transmitter and the expert field work, the team not only observed the tagged individual, but also photographed the bird at its roosting site. This provided important information and experience with regard to the type of habitats used by the Lesser Kestrels in Greece, as well as real-time observations of the tagged individual. In general, in countries, where Lesser Kestrels still breed, these birds form pre-migration concentrations, getting ready for the forthcoming migration.
These data will provide very important scientific information about the migration of the birds from the Lesser Kestrel colony established by Green Balkans in the village of Levka, Sakar SPA.
For further information, please contact:
Gradimir Gradev, Green Balkans, Project Manager
Lesser Kestrel Recovery, LIFE11 NAT/BG/360
Mobile: +359 885 609 289; Е-mail: