Chronicle of the disappearance of the Yellow-breasted Bunting (Emberiza aureola, Emberizidae, Passeriformes): Seasonal population dynamics and survival

The Yellow-breasted Bunting (Emberiza aureola) is a tropical migrant breeding in taiga zone. Once numerous, the species is on the Red List, and since 2017 has been classified as especially threatened. Biological traits of the species are still not studied enough. The purpose of the present study is to fill in the gap with original data on annual survival and seasonal peculiarities of main events on the breeding grounds and determine whether they can play a role in its unlucky fortune. Treating the trapping and marking data on the taiga population in Central Siberia, we carried out the capture-recapture analysis by means of multinomial stochastic modeling. As shown by seasonal dynamics, the phases of the annual cycle allocated to the breeding area are heavily shortened. Some features point out that the dispersal is poorly developed. Annual adult survival reached high values. At the same time, the driver of population fluctuations was the survival rate of one-year-old individuals. The survival has shrunk sharply between 1998 and 2004, so that the population has not recovered thereafter. Based on the data obtained, the connection between the extinction of the population and the recent unprecedented expansion of the species as a probable consequence of the exploitation of rice crops in Southeast Asia is discussed. An excess of food resources in the winter range determined the expansion of the breeding area and significant changes in the annual and life cycle. The sharp depletion of winter resources has led to a modern reduction in numbers and range. To maintain the population of the species, at least local elimination of the causes is necessary. Adaptations acquired during expansion will impede the recovery.