Food for flight: pre-migratory dynamics of the Lesser KestrelFalco naumanni

Observations of the lesser kestrel (Falco naumanni) in Bulgaria during the period of post-breeding dispersal

“…It was found using colour ringing and geolocators that the lesser kestrels from Southern Portugal disperse after the breeding period also mainly in a northerly direction, towards NW and NE Spain and Southern France, but part of them also remain in the breeding area until the start of the fall migration (Catry et al 2011). In Italy pre-migratory flocks of lesser kestrels are often found feeding on insects (grasshoppers) in pastures (mainly in the Festuco-Brometalia habitat) at high elevations in the karst areas of the Central and Northern Apennines, where the species does not nest at all (Sara et al 2014). Two lesser kestrels ringed during the breeding period on the island of Sicily were found later in this mountainous region in the period of post-breeding dispersal (Sara et al 2014).…”

“…In some places the post-breeding concentrations of lesser kestrels are quite numerous, annual and more or less permanent, for example in the Drino river valley in Albania with 4,000-6,000 individuals, at Badajoz, Spain with up to 3,500-4,000 individuals, in Appulia and Basciata, Italy with 10,138-16,764 individuals, and on the island of Sicily with 1,797-2,544 individuals (Minias et al 2009, Sara et al 2014). In the area to the north of the town of Kilkis in Northern Greece, 2,000 lesser kestrels were observed in August 1981 (Handrinos & Akriotis 1997).…”

“…That period is known to be the time for post-breeding dispersal and formation of pre-migratory flocks of lesser kestrels in different parts of their European breeding range, in Spain, Portugal, France, Italy and Albania (Olea 2001, Olea et al 2004, Catry et al 2011, Sara et al 2014.…”

“…These concentrations were in almost all cases in areas rich in grasshoppers, thus providing good feeding conditions for the lesser kestrels. They consisted mainly of juvenile, first-year birds and much fewer adult birds (Olea 2001, Sara et al 2014). In the past such large concentrations of lesser kestrels also regularly formed in Bulgaria when the species was still a common breeder across the country.…”

Habitat- and density-dependent demography of a colonial raptor in Mediterranean agro-ecosystems

“…Adult survival is the vital rate contributing the most to the sensitivity and elasticity of the population growth rate, followed by juvenile survival and adult fecundity. Conservation practices working on the basis of explicit factors affecting adult survival would thus be the most decisive for correct population management of the lesser kestrel across the Palearctic range (Ehrlén et al, 2001;Sarà et al, 2014). Adult survival probabilities in grassland and artichoke colonies (0.66-0.75) are comparable to those of other lesser kestrel populations (0.67-0.72: Hiraldo et al, 1996;Prugnolle et al, 2003;Serrano et al, 2005).…”