Habitat availability influences migration speed, refueling patterns and seasonal flyways of a fly-and-forage migrant.

BACKGROUND: Despite our understanding of the principal factors that shape bird migration strategies, there is conflicting evidence regarding the role of habitat in shaping migration routes and schedules, including day and night activity and differences between autumn and spring. For fly-and-forage migrants, we predict that habitat characteristics might guide migration speed, route selection and migrating schedules. METHODS: We use solar-powered GPS transmitters, obtaining high accuracy data, to monitor the migratory movements of Eleonora's falcon breeding in Cyprus, which is the easternmost breeding population of the species. We tested for potential preferences in habitat characteristics along the migration routes, separately for the northern, drier part and the more vegetated southern part of the trips. We also examined the relationship between migration speed and vegetative cover during day and at night, accounting for wind support. RESULTS: We found that tagged individuals repeatedly exhibited an anticlockwise loop migration pattern with spring routes being more easterly than autumn ones. We identified a preference for migration through vegetation-rich areas, where during daytime tagged individuals travel at slower migration speeds compared to vegetation-poor areas, indicating fly-and-forage activity. Birds roosted during most nights, combining refueling stopovers at selected vegetation-rich areas before or after crossing ecological barriers. Conversely, both during day and night, tagged individuals overflew unsuitable habitats more quickly. CONCLUSIONS: Our results suggest that habitat is an important factor in Eleonora's falcon migratory strategies. Active selection of vegetation rich areas in combination with reduced migration speeds there, allows the migrating falcons to combine migration during the day with fly-and-forage refueling, while roosting most nights.

Current and future suitability of wintering grounds for a long-distance migratory raptor.

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.