Seasonal migrations are essential parts of the annual routine in most songbird species that breed in temperate and northern latitudes. The majority of passerines are small to medium size birds, therefore some advanced techniques such as satellite telemetry are not readily applicable for the study of their migration strategies; the use of radio-telemetry, geolocators and even color-marking is limited when it comes to passerines. So far, the only way to obtain thorough information on migration strategies of most songbird species is still to study them on migratory stopover sites by means of trapping, banding and measurement of the key biometrical variables, and with the use of progressive statistical analysis methods. One of the approaches which advanced substantially our knowledge of New World's and Eurasian -African migration systems was coordinated networks of trapping stations, where songbirds were banded on larger scales and described according to a standard and compatible protocol. The recent example of international enforcements for the study of songbird migrants is a network organized in Europe and Africa with support of European Science Foundation (ESF). More than 50 trapping sites provided data for the ESF network database during 1994-1996. Analysis of the database allowed to make inferences about stopover duration, variation in body mass change rates, geographical trends of the level of fuel reserves, influence of landscape context on refueling success. Findings can be used for land and conservation management. Nowadays, migration strategies of songbirds, connectivity between breeding and wintering grounds, and important behavioral and ecological adaptations on European and North American flyways are relatively well covered. At the same time, stopover ecology of songbirds at the East-Asian Flyway is rarely a matter of researchers' attraction, most of the bird species in the Asia-Pacific region follow this flyway and it is one of the largest migration systems. Here we suggest that gaps in our knowledge of stopover ecology of East Asian songbirds might be filled by well-coordinated efforts within an international network of trapping stations. Since migration takes place on a large spatial scale, many single case studies would just have very limited interpretation and value. Currently, the Asian Pacific region has all the necessary background for such a great study. Some Asian countries developed already a substantial number of banding stations, Japan and China are among the leaders. Russia also has some groups working on the migration of passerine and other birds in the Far East. The University of Alaska Fairbanks (funded by National Institutes of Health ) for instance during 2006 - 2010 linked several russian and japanease research groups within a project of avian influenza (AI) survey, and this work might be considered as a pilot exploratory study for more substantial projects. We suggest that collaborating groups might be financed independently from different sources, but should follow the same standard protocols to get data on passage dynamic, stopover duration, fat reserves and body mass change of songbirds, both during fall and spring migration. As the basic protocol, a compatible ESF set of methods could be used, but with several modifications, and which feeds into a well-maintained open access database. The main attention should be drawn to selected model species , e.g. Siberian Rubythroat (Luscinia calliope), Arctic Warbler (Phylloscopus borealis) and Black-Faced Bunting (Emberiza spodocephala) are promising candidates. The main focus should be set on the comparison between migration strategies of populations migrating over mainland and through ocean islands. Migration connectivity might be assessed by modern means of molecular and stable isotopes analysis, but classical methods of subspecies identification based on morphometry and coloration should not be ruled out. Recoveries of banded birds should further be used to verify conclusions about connectivity. The international East Asian project would offer us a unique opportunity for filling the white spots in migration studies and the biggest challenge, to test current theories of bird migration for a sustainable management.
15 October 2010, Mokpo, Korea

Landscape context influences many aspects of songbird ecology during the breeding season. The importance of landscape context at stopover sites for migrating songbirds, however, has received less attention. In particular, landscape context may affect the availability and quality of food for refueling during stopovers, which is critical for successful migration. We evaluated the influence of woody habitat cover in the surroundings of stopover sites at several spatial extents on the hourly changes of body mass in two species of European-African forest-dwelling songbird migrants (Willow Warbler, Phylloscopus trochilus, and the Eurasian Redstart, Phoenicurus phoenicurus). Data were sampled by standardized methods from a network of ringing stations throughout Europe during the falls of 1994–1996. In both species, hourly body mass gain calculated for first captures increased with woody habitat cover. We found a similar logarithmic relationship for both species, although for Willow Warblers mass gain was more strongly related to the habitat cover within 5 km, in contrast to 3 km for Redstarts. For Willow Warblers, where sufficient data are available for each year, the relationship is consistent over the years. The shape of the relationship suggests existence of a threshold of landscape suitability for refueling at stopover sites: in sites with less than 10% of woody habitat cover, birds tend to lose body mass or to gain mass at a lower rate.