Migration of Central and East European Acrocephalus Warblers at the Eastern Adriatic Coast: An Analysis of Recoveries

Abstract

Migration routes and origins of the Reed Warbler (Acrocephalus scirpaceus), Great Reed Warbler (A. arundinaceus) and Sedge Warbler (A. schoenobaenus) populations migrating through the eastern Adriatic coast were investigated by analysing recoveries of birds ringed or found at two eastern Adriatic wetlands during autumn migration. There were 75, 104 and 63 long-distance recoveries for these three species, respectively. Great Reed Warblers from central and eastern Europe and Sedge Warblers from countries surrounding the Baltic Sea use the eastern Adriatic wetlands as stopover sites and continue their migration across the Mediterranean. Some Great Reed Warblers use south-western route during their return migration. Reed Warblers of unknown origin, presumably from eastern Europe continue their migration through south-western route to Spain (mean distance 1329.3 ± 118.0 km, n = 20; mean azimuth 251.05 ± 4.91°, n = 20; mean velocity 63.25 km/day, n = 16). Local breeding Reed Warblers migrate southeast along the eastern Mediterranean (azimuth 117.53°). Eastern Adriatic coast represents a crossroads for migratory warblers using south-western, south-eastern and central Mediterranean flyways.

Nyctalus lasiopterus Schreber, 1780 (Chiroptera: Vespertilionidae): first record for Kornati archipelago and first recent capture for Croatia

“…Its presence on the island of Kornat could possibly be explained by an abundant food source. As proposed by Kralj et al (2007), the Croatian coast represents a crossroad for migratory songbirds (warblers) using southwestern, southeastern and central Mediterranean flyways. There are few bigger wetlands in the eastern Adriatic coast such as Lake Vransko and Kolansko Blato, which represent important stopover sites for many migratory birds (Kralj et al 2007).…”

“…As proposed by Kralj et al (2007), the Croatian coast represents a crossroad for migratory songbirds (warblers) using southwestern, southeastern and central Mediterranean flyways. There are few bigger wetlands in the eastern Adriatic coast such as Lake Vransko and Kolansko Blato, which represent important stopover sites for many migratory birds (Kralj et al 2007). Some of the migratory passerines (Saxicola rubetra, Sylvia atricapilla, Sylvia borin and Phylloscopus trochilus) were recorded in the study area at the same period as our research (Š upraha in press).…”

Using stable hydrogen isotopes (δ2H) and ring recoveries to trace natal origins in a Eurasian passerine with a migratory divide

“…However, only low genetic differentiation has been found on microsatellite loci across the migratory divide (Procházka et al 2011), and no abrupt changes in morphology occur; thus we assume that the migratory divide probably arose under variable selection for optimal migration routes. It appears that only a small fraction of reed warblers of presumed central Mediterranean origin avail themselves of the central Mediterranean flyway (Dowsett-Lemaire and Dowsett 1987, Kralj et al 2007, Spina and Volponi 2008. It appears that only a small fraction of reed warblers of presumed central Mediterranean origin avail themselves of the central Mediterranean flyway (Dowsett-Lemaire and Dowsett 1987, Kralj et al 2007, Spina and Volponi 2008.…”

“…Reed warblers exhibit a slow migration with many stopovers and low fuel deposition rates (Bibby and Green 1981, Bensch and Nielsen 1999, Schaub and Jenni 2001, and the central Mediterranean flyway leading across the Alps and inhospitable deserts in central Sahara generally seems to be avoided. It appears that only a small fraction of reed warblers of presumed central Mediterranean origin avail themselves of the central Mediterranean flyway (Dowsett-Lemaire and Dowsett 1987, Kralj et al 2007, Spina and Volponi 2008.…”

Autumn migration strategy of juvenile great reed warblersAcrocephalus arundinaceuson the eastern European flyway: a spatiotemporal pattern of accumulation and utilisation of energy stores

“…Acrocephalus warblers, such as the sedge warbler A. schoenobaenus, Eurasian reed warbler A. scirpaceus, marsh warbler A. palustris and great reed warbler A. arundinaceus, are among the most common long-distance passerine migrants following the eastern route (Shirihai et al 1996;Kralj et al 2007;Procházka et al 2017). In the case of the Eurasian reed warbler, the eastern flyway is even of greater importance than the well-studied western one, regarding the estimated overall numbers of individuals following those routes on migration (Procházka et al 2017).…”