Changing drought regimes is a rising threat to biodiversity, but reported drought impacts on species varied greatly. Acknowledging the factors associating with these impacts will bring novel understandings to species vulnerability to the changes of extreme climatic events, and facilitate effective mitigation of climate change risks. Based on the peer-reviewed studies of a well-monitored taxonomic group – birds, we examined the effects of droughts on population persistence with a focus on two aspects: population abundance and reproductive success. Responses of relevant indicators of 172 bird species were extracted across eight terrestrial biomes, and the droughts triggering these responses were measured with a climate-comparable and multi-scalar index of drought severity. A meta-analysis was then conducted for the drought effect on relative abundance and reproductive success separately, which included the temporal scale and severity of droughts, as well as biological and life-history traits of species to explain the effect. We found that droughts had an overall negative effect on bird abundance and reproductive success. Apparent abundance generally declined for severe droughts lasting over a year, while the examined responses varied greatly due to the disparities of sensitivity and plasticity among species under droughts occurring at 3-month scale. Drought-induced declines in abundance were identified for species feeding on invertebrates, fruits or nectar, and species of a smaller range showed lower reproductive success during or after droughts. A small clutch size additionally contributed to the reductions in relative abundance or reproductive success under severe droughts. Our findings indicate that bird species with above drought-susceptible traits would confront greater challenges to population persistence in the regions where the duration of severe droughts extends. The study also highlights the necessity of exploring the unknowns that lie in the links between population persistence and drought responses of bird behaviors, distribution, morphology and physiology.