Aquila (2012), Vol. 119, p. 91–103 © Vidékfejlesztési Minisztérium, 2012 91 Preparatory activities for Saker Falcon (Falco cherrug) reintroduction in Bulgaria: habitat management and electrocution risk assessment Dimitar Ragyov 1 , Yordan Koshev 2 , Elena Kmetova 3 , Gradimir Gradev 3 , Georgi Stoyanov 4 , Iliyan Stoev 3 & Dimitar Marinov 3 1 Institute of Biodiversity and Ecosystem Research - Bulgarian Academy of Sciences; 2 Institute of Biodi- versity and Ecosystem Research - Bulgarian Academy of Sciences; 3 Green Balkans Federation of Nature Conservtion NGOs; 4 Central Balkan National Park Directorate ABSTRACT—The Saker Falcon (Falco cherrug) is a rare species with a very controversial present breeding status in Bulgaria. In 2009 a team of Bulgarian and foreign organizations came up with a feasibility study, discussing the need for reintroducing Saker Falcons and the means of completing the task in the country. That study formulated a number of criteria for Saker Falcon site suitability and identified the area of the Central Balkan Mountains as most suitable to support and maintain a rein- troduced population of the species. This article presents a set of preparatory pilot measures aiming at guaranteeing optimal conditions for the Saker Falcon reintroduction in terms of food supply and electrocution risk mitigation. A set of activities were carried out to support a colony of European Susliks (an important prey for Saker Falcons) through mowing and clearing tall grass and shrub vege- tation, preparing temporary holes for the animal. The management measures did not lead to a visible effect on the Suslik population during the first project year. Habitat management and the monitoring should continue 2-3 more years to see if these measures would increase Suslik numbers and enlarge their occupied area. In addition to that, a section of 20 kV electricity distribution network in the pro- posed reintroduction area was studied in order to assess the potential electrocution risk for the birds. The study located a total of 488 pylons of 6 different types and evaluated their potential threat. As a result a region with a relatively low electrocution risk was identified to assist the selection of initial Saker Falcon releases by hacking. Key words: Falco cherrug, reintroduction, European Suslik, habitat management, electrocution Correspondence: Dimitar Ragyov, Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences; 2, Yurii Gagarin Str., Sofia 1113, Bulgaria; E-mail: dimitar.ragyov@gmail.com Introduction Saker Falcon (Falco cherrug) is a rare species, included in the Red List of the Interna- tional Union for Conservation of Nature and Natural Resources (IUCN) as “Vulnerable” (IUCN, 2010). The last confirmed successful nesting of the species in Bulgaria dates back to 1997, while the last breeding attempt (unsuccessful) was documented in 1998 (D. Domuschiev, in litt.). In 2005 two adults and a young bird were observed in the begin- ning of August in the vicinity of the Central Balkan Mountains ( V. Koychev, pers. comm.) it is therefore possible that a pair had nested somewhere in the area. Otherwise in the period 2006–2009 only single birds, possibly from the wandering non-breeding Western Palearctic population were regularly seen in Bulgaria (Ragyov et al., 2009).