Survey of the Moustached Warbler (Acrocephalus Melanopogon) Populations and Migration Routes in Europe, Role of the Black Sea Population

Abstract

Data on the populations of the Moustached warbler are extremely contradictory. Clarifying population sizes is a difficult and laborious but important task. The known EU population is declining, but the conservation status of the species is considered stable. There is contradictory information about the size of the Black Sea and Danube Delta populations, but these may have a very important share in the world population. The most significant causes of the population decline are assumed to be habitat loss and deterioration of habitat status and water management characteristics. Such problems have been highlighted in numerous cases both in known nesting areas and migration routes, as well as wintering areas. As the Moustached warbler is a Natura 2000 marker species, the exploration of population sizes and population trends is also important at the European level. The Carpathian Basin population of the Moustached warbler is one of the largest European populations. The Balkan migration route plays a role in the migration of the entire Carpathian Basin population, but our research has also proved that the Mediterranean basin can also be an important area for the Black Sea population. Since 2002, we have organized 48 expeditions to the Moustached warbler migration routes and wintering grounds on the Balkan peninsula. From 2015 we turned our attention to the Black Sea population, and in the first 2 years we mainly researched in Bulgaria. Subsequently, there was already a recovery from the Black Sea population in Greece, so we wanted to intensify the research of the Moustached warbler at the Black sea. Some Hungarian researchers participated in the Chituc bird ringing camp, but we found that this was not enough, the research should be intensified in the areas and times better suitable for the Moustached warbler, more in line with the life cycle of the Moustached warbler. We took part in actions aimed specifically at revealing the migration of the Moustached warbler populations in 2021 in Moldova, in 2022 in the Chituc bird ringing camp and in 2022 and 2023 on the island Grindul Lupilor during migration time, and in the breeding season. Further Moustached warbler recoveries confirmed that the Black Sea population also uses the known Balkan regions during migration and wintering.