Rapid biodiversity loss has triggered decades of research on the relationships between biodiversity and community stability. Recent studies highlighted the importance of species traits for understanding biodiversity–stability relationships. The species with high growth rates (‘fast’ species) are expected to be less resistant to environmental stress but recover faster if disturbed; in contrast, the species with slow growth rates (‘slow’ species) can be more resistant but recover more slowly if disturbed. Such a ‘fast–slow’ trait continuum provides a new perspective for understanding community stability, but its validity has mainly been examined in plant communities. Here, we investigate how ‘fast–slow’ trait composition, together with species richness and environmental factors, regulate avian community stability at a continental scale. We used bird population records from the North American Breeding Bird Survey during 1988–2017 and defined avian community stability as the temporal invariability of total community biomass. We calculated species richness and the community–weighted mean (CWM) and functional diversity (FD) of four key life-history traits, including body size, nestling period (i.e. period of egg incubation and young bird fledging), life span and clutch size (i.e. annual total number of eggs). Environmental factors included temperature, precipitation and leaf area index (LAI). Our analyses showed that avian community stability was mainly driven by the CWM of the ‘fast–slow’ trait. Communities dominated by ‘fast’ species (i.e. species with small body size, short nestling period and life span and large clutch size) were more stable than those dominated by ‘slow’ species (i.e. species with large body size, long nestling period and life span and small clutch size). Species richness and the FD of the ‘fast–slow’ trait explained much smaller proportions of variation in avian community stability. Temperature had direct positive effects on avian community stability, while precipitation and leaf area index affected community stability indirectly by influencing species richness and trait composition. Our study demonstrates that composition of ‘fast–slow’ traits is the major biotic driver of avian community stability over North America. Temperature is the most important abiotic factor, but its effect is weaker than that of the ‘fast–slow’ trait. An integrated framework combining ‘fast–slow’ trait composition and temperature is needed to understand the response of avian communities in a changing environment. A free Plain Language Summary can be found within the Supporting Information of this article.