Search results for "satellite tracking"
showing 7 items of 7 documents
Spatial and Temporal Variability in Migration of a Soaring Raptor Across Three Continents
2019
Disentangling individual- and population-level variation in migratory movements is necessary for understanding migration at the species level. However, very few studies have analyzed these patterns across large portions of species' distributions. We compiled a large telemetry dataset on the globally endangered egyptian vulture neophron percnopterus (94 individuals, 188 completed migratory journeys), tracked across similar to 70% of the species' global range, to analyze spatial and temporal variability of migratory movements within and among individuals and populations. We found high migratory connectivity at large spatial scales (i.e., different subpopulations showed little overlap in winte…
Individual repeatability in timing and spatial flexibility of migration routes of trans-Saharan migratory raptors
2015
Satellite-tracking technology has allowed scientists to make a quantum leap in the field of migration ecology. Nowadays, the basic description of migratory routes of many species of birds has been reported. However, the investigation of bird migration at individual level (i.e. repeatability in migratory routes and timing) still remains seldom explored. Here, we investigated repeated migratory trips of a trans-Saharan endangered migratory raptor, the Egyptian Vulture Neophron percnopterus, tracked by GPS satellite telemetry. We compared between- and within-individual variation in migratory routes and timing in order to assess the degree of repeatability (or conversely, the flexibility) in mi…
The First Case of Successful Breeding of a Golden EagleAquila chrysaetosTracked from Birth by Satellite Telemetry
2007
The natal dispersal of a Golden Eagle from its natal eyrie to the site where it reproduced for the first time was monitored. After covering > 16 000 km2 in its three years of juvenile dispersal, and despite flying > 130 km from its natal site, the eagle finally settled in a vacant territory just 26 km away from the place where it had hatched. Almost 95% of the total dispersal area was visited for the first time during the first year of tracking; less than 40% of the disper- sal area was used during the remainder of the dispersal period. During dispersal the eagle regularly visited territories occupied by adult Golden Eagles. Previous records of the occupancy of the territory the eagle curre…
Living on the edge of a shrinking habitat: the ivory gull, Pagophila eburnea, an endangered sea-ice specialist.
2016
International audience; The ongoing decline of sea ice threatens many Arctic taxa, including the ivory gull. Understanding how ice-edges and ice concentrations influence the distribution of the endangered ivory gulls is a prerequisite to the implementation of adequate conservation strategies. From 2007 to 2013, we used satellite transmitters to monitor the movements of 104 ivory gulls originating from Canada, Greenland, Svalbard-Norway and Russia. Although half of the positions were within 41 km of the ice-edge (75% within 100 km), approximately 80% were on relatively highly concentrated sea ice. Ivory gulls used more concentrated sea ice in summer, when close to their high-Arctic breeding …
Natal dispersal and recruitment of two Bonelli's Eagles <I>Aquila fasciata</I>: a four-year satellite tracking study
2009
To study natal dispersal and recruitment to the breeding population in Bonelli's Eagle, two nestlings were tagged with satellite transmitters in the Iberian Peninsula in 2002. Their monthly ranges and distances were computed and fitted to regression models to describe their general trend. One bird, a female, dispersed and settled rapidly in an area which she explored intensively during four years and which finally became her first breeding site. The natal dis- persal distance was 441 km, and the bird cannot therefore be considered philopatric. The other bird, a male, alternated between long travelling episodes and settlement in particular areas, exploring different regions both distant from…
Scavengers on the move: behavioural changes in foraging search patterns during the annual cycle
2013
Background: Optimal foraging theory predicts that animals will tend to maximize foraging success by optimizing search strategies. However, how organisms detect sparsely distributed food resources remains an open question. When targets are sparse and unpredictably distributed, a Lévy strategy should maximize foraging success. By contrast, when resources are abundant and regularly distributed, simple Brownian random movement should be sufficient. Although very different groups of organisms exhibit Lévy motion, the shift from a Lévy to a Brownian search strategy has been suggested to depend on internal and external factors such as sex, prey density, or environmental context. However, animal re…
Mesoscale eddies, surface circulation and the scale of habitat selection by immature loggerhead sea turtles
2007
17 pages, 8 figures, 6 tables