Trait-based approaches have revolutionized ecology by enabling the characterization of biodiversity through species’ ecological strategies. The rapid development of multiple databases has shifted the focus from data availability to the critical evaluation of trait types to explore the functional diversity of taxonomic groups. Central to this approach is the construction of a functional space, typically built by aggregating available traits into a unique multivariate framework. However, such trait aggregation may lead to ecologically unbalanced representations, where statistical variance is dominated by a subset of traits (e.g., body size), thereby masking functional strategies such as diet or reproduction. We here argue for shifting trait-based approaches from a unique functional space to multiple, ecologically explicit trait spaces, each representing a specific aspect of species’ ecological roles. Using birds as a case study, we show how this framework enhances a better understanding of biogeographic patterns and provides more targeted insights about extinction risks. We advocate for the adoption of function-related trait spaces as a foundation for trait-based ecology and conservation, offering greater ecological resolution than aggregated global indices.