Onset of natal dispersal in Peregrine Falcon from Mediterranean islands (Italy)

Abstract

Basic information on natal dispersal of Peregrine Falcons is virtually lacking in Europe, despite increased attention on this species, and the sensitivity of this stage in the Peregrines’ life history. In this study, we collected satellite telemetry data during the onset of natal dispersal of 19 Peregrine Falcons tagged in Sicily and the Aeolian archipelago (Italy). We divided the onset of dispersal into the following 3 periods: post-fledging dependence period (PFDP), wandering, and wintering. PFDP lasted on average 47±16 days, during which young peregrines moved very little (0.167 km), and explored small areas (0.226 km2) far from the nest cliff, and showed no sex differences. The wandering phase was highly individualistic, with median net displacements of 23.97 km. Both PFDP and wandering bearings were oriented towards NNE-ESE. Only five individuals went sporadically outside the island borders. During their first winter, Peregrines had a mean home range of 135.65±82.31 km2 spatially scattered across Sicily and mainly composed of open habitats, like cereal steppes, arboreal crops and agri-mosaics. Individuals had a dissimilar assortment in habitat composition, however the urban habitat was the most selected and the woodland the least. At night, during both wandering and wintering phases Peregrines used rocks, cliffs and electricity pylons in frequencies not statistically different between sex, phase and type of roost. Only two individuals had significant use of pylons and one of rocks. The multifaceted framework of Peregrine Falcon’s natal dispersal was described here for the first time in a Mediterranean population.

Genetic variability in Peregrine Falcon populations of the Western Palaearctic region

“…The former has been suggested to show a character introgression with the close French F. p. peregrinus population that would produce variable phenotypes (Zuberogoitia et al 2009) and the signals of non-random mating would stabilize pairs maintaining phenotypical variation (Figure 4). While the Sicilian population appears to be quite isolated as judging from the presence of an exclusive and highly frequent H1 haplotype and the lack of dispersal (see Bondì et al 2018). Despite this presumed insular condition, Sicilian Peregrine Falcons show quite large deviation from the expected brookei 23 C. Mengoni,I.…”

“…It remains an open question whether such a non-random mating signal could be depending by chance from the specific sample here used, or from the peculiar condition of the Biscay population, at the border between the Spanish 'brookei' and the French 'peregrinus' ranges (Zuberogoitia et al 2009). Otherwise, first investigation on natal dispersal has not yet recorded emigration from Sicily (see Bondì et al 2018), though we cannot still exclude immigration from continental Italy. This condition goes hand in hand with the large number of exclusive alleles found in the Sicilian falcons, so to allow supposing a quite close population.…”

“…This condition goes hand in hand with the large number of exclusive alleles found in the Sicilian falcons, so to allow supposing a quite close population. If this would be the case, the population of Peregrine Falcons in this island, currently estimated at 240-250 pairs (see Bondì et al 2018), would be large enough to limit non-random mating among individuals.…”

Northerly dispersal trends in a lowland population of Peregrines Falco peregrinus in southwest England

“…At least 12 individuals (18% of our total) were resighted at confirmed breeding locations which they used for nesting during the summer months, and a further 13 were over two years of age and likely to be at unconfirmed breeding locations. The remaining 41 were two years old or younger and still in their predispersal or dispersal phase (Cramp & Simmons 1980, Bondì et al 2018, Morton et al 2018. Peregrines are capable of breeding from their second calendar year onwards, when they are sexually mature.…”

“…However, to analyse the direction of travel, only individuals (n = 58) that had travelled more than 1 km from the ringing location after 90 days were included. After 90 days it is highly likely a juvenile Peregrine has begun its wandering phase and moved away from its natal area; using 1 km excludes those individuals that had not moved any significant distance from where they had hatched (Cramp & Simmons 1980, Ratcliffe 1993, Bondì et al 2018.…”