Summer pre-breeding movements of Eleonora’s Falcon Falco eleonorae revealed by satellite telemetry: implications for conservation

Abstract

SummaryRecent advances in bird tracking technologies are revealing that migratory birds use temporal staging sites other than breeding and wintering areas, and these areas deserve conservation efforts. Eleonora’s Falcon Falco eleonorae is a long-distance migratory raptor that breeds colonially on islands and is considered a priority species for conservation. Anecdotal observations indicate that during the pre-breeding period, Eleonora’s Falcons stay in inland areas far away from the colonies, but, to date there are no detailed data concerning the connectivity between these areas and breeding colonies. Using satellite telemetry, we analysed data from four summering events belonging to three individuals breeding in two colonies in the Western Mediterranean (Spain). All of them made inland movements in areas up to c.400 km distant from the respective breeding colonies, visiting several habitats, from forests to arable lands, probably taking advantage of high densities of insects. Perturbations occurring in these areas could threaten Eleonora’s Falcons with serious consequences at the population level. We suggest that conservation measures implemented at breeding and wintering grounds may not suffice and that temporary staging areas should be identified at a larger scale and deserve protection as well.

Seasonal and daily activity patterns by Eleonora’s FalconFalco eleonoraebased on GPS telemetry: a contribution to the species’ movement ecology at its breeding grounds

“…A similar activity pattern was shown for two adult female and one juvenile Eleonora's Falcons originating from the Balearic and Columbretes islands (Spain), respectively (Mellone et al 2013a) and one female adult Eleonora's Falcon originating from San Pietro island (Italy; Gschweng et al 2008). During the pre-breeding period and especially in June the Spanish falcons roamed in France, Spain and Italy occurring in areas more than 500 km from their colonies until the onset of the breeding period.…”

The trans‐equatorial loop migration system of Eleonora’s falcon: differences in migration patterns between age classes, regions and seasons

“…Despite the spring routes being slightly shorter than the autumn ones, adults performed longer stop‐overs in spring than in autumn, resulting in a longer time spent during spring migration (9% vs 7% of the annual cycle), suggesting a lack of urgency in reaching the breeding areas. In fact, Eleonora’s falcons do not immediately occupy their breeding colonies after spring arrival, but, instead, spend up to two months in pre‐breeding areas that may be far away from the colonies (18% of the annual cycle; Mellone et al 2013), delaying their reproduction until mid‐summer, unlike other Palearctic migratory birds (Walter 1979, Mellone et al 2012c).…”

Ecological Specialization to Fluctuating Resources Prevents Long-Distance Migratory Raptors from Becoming Sedentary on Islands

“…However, long-term studies seem to contradict, at least in part, this assumption. Data from satellite-tracked Eleonora’s falcons from Spain, Italy and Greece demonstrate that 2 nd calendar-year birds (n = 6) do in fact leave the wintering grounds during spring, heading northwards [8], [18], [19]. Although many of them may not necessarily reach their natal colonies the first year [20], satellite telemetry data, banding recoveries and observations show that these young birds disperse widely throughout the Mediterranean basin [14], [17], [18], [20], thus becoming distributed across potential future breeding sites during their first summer.…”

“…Data from satellite-tracked Eleonora’s falcons from Spain, Italy and Greece demonstrate that 2 nd calendar-year birds (n = 6) do in fact leave the wintering grounds during spring, heading northwards [8], [18], [19]. Although many of them may not necessarily reach their natal colonies the first year [20], satellite telemetry data, banding recoveries and observations show that these young birds disperse widely throughout the Mediterranean basin [14], [17], [18], [20], thus becoming distributed across potential future breeding sites during their first summer. For instance, the only 2 nd calendar-year individual satellite-tracked during its first full spring migration, wandered around mainland Spain and France until September, before it finally visited its natal colony on the Columbretes Islands late in the breeding season [18].…”

“…Although many of them may not necessarily reach their natal colonies the first year [20], satellite telemetry data, banding recoveries and observations show that these young birds disperse widely throughout the Mediterranean basin [14], [17], [18], [20], thus becoming distributed across potential future breeding sites during their first summer. For instance, the only 2 nd calendar-year individual satellite-tracked during its first full spring migration, wandered around mainland Spain and France until September, before it finally visited its natal colony on the Columbretes Islands late in the breeding season [18]. Furthermore, on the basis of banding recoveries, [16] reported six 2 nd calendar-year individuals re-sighted 50–500 km (n = 3) and >500 km (n = 3) away from their natal colony in Greece.…”