how do spoonbills and other iconic migrants cope
in a world of rapid wetland loss?
[update coming soon]
[update coming soon]
[update coming soon]
[update coming soon]
[update coming soon]
Work in progress: time series of January fixes of Dutch and German GPS-tagged Godwits overlayed on a flooding map (NDWI < 0 = wet) of the Guadalquivir delta.
understanding how eleonora´s falcons tune their trans-African migrations to environmental conditions
Pale morph Eleonora’s Falcon carrying an UvA-BiTS GPS logger. - Photo by Laura Gangoso.
Eleonora’s Falcons (Falco eleonorae) engage in one of the most remarkable migrations of all raptors. They are highly aerial hunters that breed colonially on islands and coastal cliffs throughout the Mediterranean Basin and in the East Atlantic. While this species preys on flying insects during most of the year they raise their offspring almost entirely on a diet of migratory passerines. After their exceptionally late breeding season all Eleonora’s Falcons escape he European winter by migrating to northern Madagascar. During spring migration falcons from all across the breeding range appear to converge through a stop-over hot-spot in the Greater Horn of Africa before diverging into distinct trans-Saharan flyways.
During my postdoctoral research in the Figuerola group at the Dept. of Wetland Ecology at Estación Biológica de Doñana (EBD-CSIC, Sevilla, Spain) I showed how wind regimes shape the trans-African migrations of this enigmatic raptor. We are wrapping up an investigation on the drivers and limits of non-stop and nocturnal flight in this typically diurnal species. Moreover, by tracking repeated journeys for the same individuals across multiple years we could untangle how much of the overall variation in route choice and timing in our study population can be explained by internal factors (i.e. genetics and experience), and whether individual diversity their strategies more over some landscapes and environmental contexts than others (in review).
This study is funded by a Juan de la Cierva Formacion Fellowship and integrated in the broader study on the ecology of Canarian Eleonora’s Falcons lead by Dr. Laura Gangoso.
how do juvenile honey buzzards learn safe migration routes between europe and africa?
Juvenile Honey Buzzards (Pernis apivorus) Ivar and Sven at their natal nest in southwestern Finland. This was an unlikely brood, as Ivar died shortly after leaving the nest in Finland, and Sven perished in Algeria after a two-day flight across the Mediterranean during which he stopped to spend the night on a fishing vessel. - picture by Patrik Byholm
Over the past few decades tracking technology has allowed us to map migration strategies for a wide range of species. However, in order to maximise the amount of data collected with expensive tracking devices most studies have focused on adult migrants. As such, we know very little about the way in which migrant birds learn their often highly complex and flexible migration routines, and how this leads to the emergence of individual and population-specific migration patterns. This is also true for the species on which I conducted most of my migration research so far: the European Honey Buzzard (Pernis apivorus). However, since 2011 Patrik Byholm at the Bioeconomy Research Team of Novia University of Applied Sciences has equipped more than 30 juvenile and 10 adult European Honey Buzzards (Pernis apivorus) born or breeding in southwestern Finland with satellite transmitters and GPS-GSM loggers. The Finnish Honey Buzzard project thus provided an unique opportunity to investigate how innate and external factors shape individual migration routines in a long-lived thermal-soaring migrant.
Routes taken by juvenile Honey Buzzards on their first autumn migration from Finland to sub-Saharan Africa, coloured according to the longitudinal wind speeds they encountered along the way. For full details see Vansteelant et al. 2017 in Proceedings of the Royal Society B: Biological Sciences.
The learning process of Honey Buzzards is of particular interest because of the pronounced age-specific differences in migration behaviour. While adults engage in highly synchronised migrations along narrow overland migration corridors, juveniles depart on their first autumn migration approx. two weeks later and find their own way over a broad front, often engaging in long and risky flights over the Mediterranean Sea. How they eventually learn to use the traditional overland flyways is a mystery.
As a first step towards unravelling the migratory development in this species I analysed how wind and geography shape the first autumn migration and distribution of juvenile Honey Buzzards across sub-Saharan Africa. This revealed that the wind conditions that these birds encounter on their first migration determine the longitude at which they finally settle south of the Sahara, more so than individual (innate) differences in orientation (Vansteelant et al. 2017).
In a follow-project I am currently analysing how the route choice and migratory schedules of these birds develop with age and experience. Results are expected to be published by summer 2019.