A Lesser Kestrel in flight with an Argos PTT. (Credits Green Balkans)
21.08.2018 Birds tracking

Lesser Kestrels back in Bulgaria

Endangered species can be locally so. The Lesser Kestrel, a small falcon, was all but extinct in Bulgaria. A project enabled to reintroduce the prey bird in this country, with satellite tagging and tracking of its migration, to understand the best way to protect it.

The Lesser Kestrel (Falco naumanni) is a small bird of prey. It is mostly insectivorous and is thus impacted by widespread use of pesticides. It did not nest in Bulgaria in the last decades (since the 1980s), while it was common in the past, and is thus classified as “critically endangered” in this country. In 2008 the Green Balkans organization launched activities to recover the Lesser Kestrel as a breeder by reinforcement of the species in Bulgaria, including translocation of chicks born in Spain. In 2014, the species has returned to Bulgaria after almost 30 years of absence.

Lesser Kestrel mock-up with a 5-g Argos PTT (Credits GreenBalkans)
Lesser Kestrel mock-up with a 5-g Argos PTT (Credits GreenBalkans)
photo of a Lesser Kestrel (Credits Green Balkans)
photo of a Lesser Kestrel (Credits Green Balkans)

Before 2015, the birds were marked with rings. Since then, small 5-g Argos solar PTT are used, attached to the back of the bird (“backpack” type), not exceeding 3-4% of the body weight of the birds tagged. They do not affect the behavior of the migrating diurnal birds of prey and fall when the attachment breaks after some time. It was the first time in the Balkans such Argos satellite transmitters are used for Lesser Kestrels.

The Lesser Kestrels tagged with Argos transmitters reveal previously unknown peculiarities of the life of these rare falcons: where the foraging grounds are, how far they go from the colony, where they rest in the heat, where they roost, how much time they spend in the area of the colony – feeding the chicks, as well as in its vicinities – hunting and searching for food, as well as many other details that can only be identified through transmitters. The Argos satellite telemetry is also a way of knowing what happens during the wintering migration to Africa. Five birds over the six equipped were successful in completing the Autumn migration, reaching the wintering areas in Africa and back to the breeding territory (around 4000 km), two of them two years in a row. The wintering areas were thus determined to be in Niger, Nigeria, and Chad, with a pre-migrational gathering in Greece, stopover sites in Turkey, Greece, Libya, and Egypt.

Tracks of five Lesser Kestrels from Bulgaria to Africa and back. The whole round trip represents around 4000 km (Credits Green Balkans)
Tracks of five Lesser Kestrels from Bulgaria to Africa and back. The whole round trip represents around 4000 km (Credits Green Balkans)

 

Acknowledgments:

The Green Balkans’ efforts for satellite tracking and conservation of Lesser Kestrel in 2018 are supported by the German Foundation EuroNatur – www.euronatur.org”

References:

Featured photo:

A Lesser Kestrel in flight with an Argos PTT. (Credits GreenBalkans)

http://www.greenbalkans.org/en/Lesser_Kestrels_return_work_continues_-p6671

http://www.greenbalkans.org/en/Green_Balkans_has_been_tracking_radio_tagged_Lesser_Kestrels-p5314

Gradev, Gradimir & Marin, Simeon & Zhelev, Pavlin & Antolín, José. (2015). Recovering the lesser kestrel (Falco naumanni) as a breeder in Bulgaria. Annuaire de l’Université de Sofia “St. Kliment Ohridski” Faculte de Biologie. 136-144.