Mapping stopover site quality and migration patterns within the Euro-African migration system and beyond
Bird ringing has provided extremely valuable data to describe migration routes, population trends, and many other ecological processes of hundreds of bird species. Many studies were conducted at a local scale (i.e. within a single location), while successful attempts of evaluating networks of several stations were done in the past (e.g. the Mettnau-Reit-Illmitz project, the Progetto Piccole Isole, the Progetto Alpi, Operation Baltic, etc.). These initiatives showed the value of considering data from a broad geographical perspective (i.e. from the surrounding area up to the flyway scale) when trying to interpret migration patterns observed locally. We would like to take the opportunity of the recently started EUFLYNET COST Action (www.euflynet.eu) to bring together ringing datasets collected during migratory periods to identify key regions used by migratory birds, map stopover site quality over time and space, and describe population fluctuations and phenological changes on a continental scale.
The aim is to integrate ringing data from ringing stations across Europe and beyond in one database to enable the mapping of parameters related to migration (see below) over large geographical and temporal scales. Ultimately, these data will be summarized and accessible via a user-friendly tool made available to conservation scientists and policy makers.
Using ringing datasets from stopover sites across the continent will enable us to address the following questions:
1.      Stopover ecology/physiology. Several aspects that can be related to survival during migration can be investigated, such as
a.      Body mass changes across the flyway (to identify the important sites for accumulating fuel, to identify the strategy of fuelling in different species and populations);
b.      Stopover duration in relation to habitat and location (e.g. vicinity of ecological barriers);
c.      Fuel deposition rates in relation to environmental variables, competition, etc.;
d.      Propensity of stopover at given locations by different species (i.e. probability of transients);
e.      Long-term changes in all of the above.
2.      Changes in phenology. While they have been described in many studies, we still do not know exactly whether the changes are uniform throughout the species’ range or happen differently depending on location and species. We will update the information on changes in migrants’ phenology over time by integrating information from long-term datasets at the flyway scale and comparing between flyways. Knowing the patterns of change, we will be able to investigate the drivers of these changes and relate them to changes in climate and environmental factors.
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3.      Population structure. In dimorphic species, sex ratios can be determined and used as indicators of population structure. The information on the migrants’ sex will allow to investigate differential migration by sex, and any sex-specific changes in phenology.
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4.      Breeding productivity. The proportion of first-year birds trapped during migration will give insights on the productivity of each species during a given season. Again, this will be integrated at a flyway scale to identify local differences.
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5.      Recruitment. In species for which age is still identifiable in spring, the proportion of second-year birds can be used as a proxy for recruitment in the breeding population, and an indirect measure of overwinter survival (for both young and adult birds).
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The starting aim is to analyse data collected so far and publish scientific articles Following this, a more long-term aim is to investigate the possibility of a continuously updated database that would allow addition of old data as they are discovered and disclosed, as well as newly collected data. This would lead to the creation of an online tool offering visualizations of the past and current situation for migrant species at studied locations while fully crediting data owners. We are therefore calling for collaboration from as many participants as possible!