The next common and widespread bunting to go? Global population decline in the Rustic Bunting Emberiza rustica

Populations of several long-distance migratory songbirds in Eurasia are in peril, drastically illustrated by the recent range-wide population collapse in the Yellow-breasted Bunting Emberiza aureola. There are signals of a strong decline also in the Rustic Bunting E. rustica, but no range-wide assessment of population trends in this superabundant and widespread bunting species has yet been undertaken. The conservation status of Rustic Bunting is 'Least Concern' on the global IUCN Red List, but it has recently been upgraded to 'Vulnerable' on the European Red List. To assess the Rustic Bunting's global conservation status we compiled, for the first time, population data across its breeding and wintering ranges. The analysis reveals a 75-87% decline in overall population size over the last 30 years and a 32-91% decline over the last 10 years. The trend estimates indicate that the long-term (30-year) range-wide population decline in the Rustic Bunting is of similar magnitude to two well-known examples of declining species within the same genus, the Yellow-breasted Bunting and the Ortolan Bunting E. hortulana. The magnitude of the range-wide population decline over the last 10 years suggests that the Rustic Bunting could be upgraded from 'Least Concern' to 'Vulnerable' or 'Endangered' on the IUCN global Red List. Agricultural intensification in the wintering range and intensified levels of disturbance, including logging and fire, in the breeding range could be important drivers of the range-wide population decline, and persecution could also contribute. Untangling threat factors and their interactions on Rustic Bunting is necessary for conservation, but hampered by our currently limited understanding of the relationships between population dynamics and different threats.