Eleonora's falcon ( Falco eleonorae ) is a rare raptor species that delays its breeding period until late summer to feed its young with passerines at the peak of autumn migration. Since the 1950s, this slender winged falcon has been believed to migrate along a historical route via the Red Sea to its main wintering area in Madagascar. In our study, we used satellite telemetry to investigate the real migration route of Eleonora's falcons and found that the species displayed a highly individual migration pattern. Furthermore, juvenile falcons migrated via West Africa to Madagascar and two juveniles could be tracked during spring migration and to their summering areas in East and West Africa. As juveniles migrated independently of adults, we discuss inherited navigation strategies forming part of a complex navigation system. We propose the idea of an orientation mechanism that naive falcons could apply during their long-distance migration towards their faraway wintering area located in the open ocean.

Summary 1.Despite the wealth of data available from satellite tracking (ST) studies, such data have rarely been used to model species distributions. Using a novel method, we show how to exploit satellite data to analyse whether and how a migratory species responds to fluctuating environmental conditions in its wintering area. This is particularly crucial for establishing comprehensive conservation measures for rare species in areas that are threatened by increasing land use and climate change. 2. We use ST data of Eleonora's falcon Falco eleonorae, a long-distance migratory raptor that winters in Madagascar, and assess the performance of static species distribution models (SDM) as well as multi-temporal models. ST data were derived from seven falcons tracked during three consecutive wintering periods and for a total of 2410 bearings, of which 512 locations were used in SDMs. We employed environmental predictors (climate, topography and land cover) with a spatial resolution of 30 arc seconds (c. 1 km 2 ) to match rigorously filtered ST data with an accuracy of £1 km. 3. We first created a model with low temporal but high spatial resolution (half-year). To predict suitable habitat for each month of the wintering season, we took advantage of the high temporal resolution inherent in ST data and employed temporally corresponding remote sensing data [Normalized Difference Vegetation Index (NDVI) 10-day composites] together with other variables to create monthly models. 4. We show that ST data are suited to build robust and transferable SDMs despite a low number of tracked individuals. Multi-temporal SDMs further revealed seasonal responses of the study species to changing environmental conditions in its wintering area. 5. Synthesis and applications. We present a transferable approach to predict the potential distribution of organisms as well as their dynamic response to changing environmental conditions. Future conservation management plans could include the prediction of a species' reaction to changing land-use practices or climate change based on the methodology proposed here. This would provide an early warning system for the decline of populations wintering in remote areas that underlie strong climatic fluctuations.

Eleonora's Falcon (Falco eleonorae) is an endemic breeder of the Mediterranean Sea and the Canary Islands that overwinters in Madagascar and surrounding areas. Recent telemetry studies have revealed the migratory journey of falcons from the western and central Mediterranean breeding colonies. Our study complements the puzzle of the species' migration providing data from an eastern Mediterranean breeding colony. In this paper, we describe for the first time the migratory routes of four falcons originating from the Aegean Sea, the core of the species' breeding range. We tracked two adults and two immature siblings to their wintering grounds in Madagascar. According to our results, the timing of migration was consistent with previous studies. Our findings also suggest that the falcons adjust their flight speed according to the environmental conditions encountered en route, by accelerating during open-sea and desert crossings and by slowing down in potential foraging areas. Moreover, the selection of common staging areas, both among the two siblings and among the two adults, highlights the role of these areas in the migratory cycle of the species. Finally, according to the home-range analysis on the wintering grounds, space use was rather variable across the four tracked falcons. Still, the falcons were more frequently observed within the submontane forest, one of the last patches of primary rainforest in Madagascar. Thus, future studies aiming at unveiling the ecological requirements of the species in its wintering quarters are considered as top priority.

Conservation of migratory species faces the challenge of understanding the ecological requirements of individuals living in two geographically separated regions. In some cases, the entire population of widely distributed species congregates at relatively small wintering areas and hence, these areas become a priority for the species’ conservation. Satellite telemetry allows fine tracking of animal movements and distribution in those less known, often remote areas. Through integrating satellite and GPS data from five separated populations comprising most of the breeding range, we created a wide habitat suitability model for the Eleonora’s falcon on its wintering grounds in Madagascar. On this basis, we further investigated, for the first time, the impact of climate change on the future suitability of the species’ wintering areas. Eleonora’s falcons are mainly distributed in the north and along the east of Madagascar, exhibiting strong site fidelity over years. The current species’ distribution pattern is associated with climatic factors, which are likely related to food availability. The extent of suitable areas for Eleonora’s falcon is expected to increase in the future. The integration of habitat use information and climatic projections may provide insights on the consequences of global environmental changes for the long-term persistence of migratory species populations.