Vulnerable bird species and avian mortality due to predation by domestic cat (Felis catus) in anthropogenically transformed landscapes of the Bukovynian Carpathians

The domestic cat (Felis catus) poses a significant threat to bird fauna, particularly in the urbanised, anthropogenically transformed landscapes of the Bukovynian Carpathians, Ukraine. This study aimed to determine the annual bird mortality rate due to cat predation and identify vulnerable species to this threat. Using the Monte Carlo method with 10,000 iterations, mortality rates were calculated. Data were gathered from sociological surveys, field observations, and scientific publications. The methodology included estimating the number of rural pets and feral cats across 877.9 km², calculating population density, and assessing bird predation. Annually, an average of 509,000 birds are killed, with a 95% mortality estimate range between 188.6 thousand and 1,008.6 thousand, which highlights the cats’ impact on local bird populations. Linear regression models were developed to predict bird mortality based on cat population size. The regression formulae are nBFC = 44.10 * nFC for feral cats and nBRP = 32.92 * nRP for rural pets. A total of 62 vulnerable bird species were identified in these landscapes of the Bukovynian Carpathians.