WE HAVE EXPANDED !!!

Following some recent events, the GEP has expanded and a part of it has migrated. We thought it will be better to mark this change by making new entities. The part of the GEP that remained in Mallorca is now named the Grupo de Ecologia y Demografia Animal (GEDA). Its activities can be followed here (at http://www.animaldemography.blogspot.com.es/).

The mistery of the route to the Cantabric Sea solved!

Tracking data offered a first breakthrough to solve the mystery of the route to the Cantabric Sea.   
Yellow-legged gulls from the Balearic islands have been regularly seen in the Cantabric coast, but the route to Northern Spain was a mystery. Do they fly around the Iberian peninsula or throught the Ebro valley ? Do they use the Ebro river as a landmark? Do they reach the Cantabric sea from France? 
Last year preliminary data provided a first piece of the puzzle when a gull moved North following the Ebro river to Zaragoza. However the radio failed at the end of the summer and the route to the Cantabric sea along the Ebro river was not proved. This summer tracking data deliver the solution to the mystery, showing what is likely to be the main route to the Cantabric Sea: the Ebro valley. Interestingly, the route seems to pass north of the river and through the Basque Mountains at Estella. To be continued....

Audouin 's gull movements: The book !

New book on Audouin's gull spatial ecology

Monograph published by SEO/BIRDLIFE

Just hot off the presses, the monograph is an up-to-date study about the spatial ecology and migration of the Audouin’s gull, by exploiting radio-tracking data collected by SEO/BirdLife combined with more than 63000 ring resights performed by GEP corresponding to more than 45000 chicks ringed over the years. The book includes many figures and maps elaborated using information from those resights and GPS and satellite tracking data from several colonies in the Spanish Mediterranean. The publication largely contributes to understanding the phenology and spatio-temporal distribution patterns of the species across the year, including its migration routes. The text is in Spanish with an English summary. Last but not least, do not miss the nice pictures included! You can have a look at the pdf freely available here:

http://www.seo.org/boletin/seguimiento/migracion/01_gaviota_audouin/

New Publication !

Sergio, F., Taferna A., De Stephanis, R., López Jiménez, L., Blas, J., Tavecchia, G., Preatoni, D., and Hiraldo, F., 2014: 'Individual improvements and selective mortality shape lifelong migratory performance'. Nature. doi:10.1038/nature13696

Billions of organisms, from bacteria to humans, migrate each year and research on their migration biology is expanding rapidly through ever more sophisticated remote sensing technologies. However, little is known about how migratory performance develops through life for any organism. To date, age variation has been almost systematically simplified into . These comparisons have regularly highlighted better migratory performance by adults compared with juveniles, but it is unknown whether such variation is gradual or abrupt and whether it is driven by improvements within the individual, by selective mortality of poor performers, or both.

Here we exploit the opportunity offered by long-term monitoring of individuals through Global Positioning System (GPS) satellite tracking to combine within-individual and cross-sectional data on 364 migration episodes from 92 individuals of a raptorial bird, aged 1–27 years old. We show that the development of migratory behaviour follows a consistent trajectory, more gradual and prolonged than previously appreciated, and that this is promoted by both individual improvements and selective mortality, mainly operating in early life and during the pre-breeding migration. Individuals of different age used different travelling tactics and varied in their ability to exploit tailwinds or to cope with wind drift. All individuals seemed aligned along a race with their contemporary peers, whose outcome was largely determined by the ability to depart early, affecting their subsequent recruitment, reproduction and survival. Understanding how climate change and human action can affect the migration of younger animals may be the key to managing and forecasting the declines of many threatened migrants.

See also at IMEDEA (CSIC-UIB) and IMEDEA Divulga here