The saker falcon (Falco cherrug) population, diet and nest boxes in Slovakia: LIFE-project report 2011–2014

Abstract

From October 201 0 until December 201 4 the LIFE09 NAT/HU/000384 project was implemented in four Special Protected Areas in Slovakia. The recent project was complementary to a previous LIFE project implemented between 2006 and 201 0. Both projects supported regular monitoring of the population of saker falcon and new approaches to conservation of the species. The LIFE09 project helped to increase knowledge about the prey composition and the behaviour of the species. The population was strongly affected in 201 3 by extremely bad weather conditions (1 .79 fledglings/breeding attempt). Although the total number of saker falcon pairs in Slovakia is thought to be higher, 31 pairs were breeding in 201 4. By analysis of the diet (2991 individuals), 47 prey species were identified, from which birds were predominant (80%). More than half of the diet consisted of feral pigeons (Columba livia f. domestica) (59%)

Changes in nesting habitat of the saker falcon (Falco cherrug) influenced its diet composition and potentially threatened its population in Slovakia in the years 1976–2016

“…In western Slovakia we recorded specialization in hunting seagulls among some saker pairs, especially the blackheaded gull (Chavko et al 2014). Similar specialization was found by Horák (1998) in southern Moravia.…”

“…On the other hand, mammals are still a dominant diet component in Romania and Bulgaria (Baumgart 1971), and mainly in Asia. In central Kazachstan the redcheeked ground squirrel (Spermophilus erythrogenys) and great gerbil (Rhombomys opimus) form the dominant component (together almost 50%) in the saker falcons' diet (Nedyalkov et al 2014) These are mediumsized mammals like those which used to form the dominant diet component in Slovakia in the past (Chavko et al 2014). Similar incidence of mammals (together up to 70%) is reported in Mongolia (Gombobaatar et al 2006), of which the dominant prey is Brandt's vole (Lasi-opodomys brandtii; equivalent to common vole in the conditions of central Europe).…”

“…Obuch & Chavko (1997) studied the falcons' diet in western Slovakia especially in the period from 1978 to 1995, when the majority of nests was still located in the highlands (Chavko 2002a). and Chavko et al (2014) then reported updated information about the species' diet in Slovakia. The situation has changed in Slovakia compared to the state found in those published works, and we have comprehensively reworked the data covering the whole monitored time period, focusing on finding the missing correlations between changes in nesting habitat, food sources and population threats.…”

“…An analogical situation of reduction in trophical and topical conditions, is becoming more and more serious in other European states as well (Donald et al 2001, Butler et al 2010, Vermouzek & Zámečník 2017. The installation of boxes on pylons has led to a clear improvement in nesting conditions for saker falcons across the intensively farmed lowlands (Zink & Izquierdo 2012, Chavko et al 2014. As a result, the availability of food may now be considered as the most significant motivating factor for reproduction and successful nesting, which correlates directly with the range of nesting opportunities and the level of incidence of threats (especially human disturbance and birdrelated criminality.…”

Impact of management measures on the European ground squirrel population development

“…Ground squirrels (Spermophillus sp.) represent a significant dietary element of the Eastern imperial eagle Aquila heliaca (Del Hoyo et al, 1995;Haraszthy et al, 1996;Belik et al, 2002;Chavko et al, 2007;Karyakin et al, 2011) and the saker falcon Falco cherrug (Obuch and Chavko, 1997;Chavko, 2010;Chavko and Deutschová, 2012), but presently the ground squirrel representation in the diets of both species in Central Europe is significantly lower (Horváth et al, 2010(Horváth et al, , 2018Chavko et al, 2014). The European ground squirrel is an important part of the food chain of raptors (Ružić, 1978).…”