3 research outputs found
The interplay of wind and uplift facilitates over-water flight in facultative soaring birds.
Flying over the open sea is energetically costly for terrestrial birds. Despite this, over-water journeys of many birds, sometimes hundreds of kilometres long, are uncovered by bio-logging technology. To understand how these birds afford their flights over the open sea, we investigated the role of atmospheric conditions, specifically wind and uplift, in subsidizing over-water flight at a global scale. We first established that ΔT, the temperature difference between sea surface and air, is a meaningful proxy for uplift over water. Using this proxy, we showed that the spatio-temporal patterns of sea-crossing in terrestrial migratory birds are associated with favourable uplift conditions. We then analysed route selection over the open sea for five facultative soaring species, representative of all major migratory flyways. The birds maximized wind support when selecting their sea-crossing routes and selected greater uplift when suitable wind support was available. They also preferred routes with low long-term uncertainty in wind conditions. Our findings suggest that, in addition to wind, uplift may play a key role in the energy seascape for bird migration that in turn determines strategies and associated costs for birds crossing ecological barriers such as the open sea
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.Peer reviewe