Body mass has been considered one of the most critical organismal traits, and its role in many ecological processes has been widely studied. In hummingbirds body mass has been linked to ecological features like foraging performance, metabolic rates, and cost of flying, among others. We used an evolutionary approach to test if body mass is a good predictor of two of the main ecological features of hummingbirds: their abundances and behavioural dominance. To determine whether a species was abundant and/or behaviourally dominant, we used information from the literature on 249 hummingbird species. For abundance we classified a species as “plentiful” if it was described as the most abundant species in at least part of its geographic distribution, while we deemed a species to be “behaviourally dominant” when it was described as pugnacious (notably aggressive). We found that plentiful hummingbird species had intermediate body masses and were more phylogenetically related to each other than expected by chance. Conversely, behaviourally dominant species tended to have larger body mass and showed a random pattern of distribution in the phylogeny. Additionally, small-bodied hummingbird species were not considered plentiful by our definition and did not exhibit behavioural dominance. These results suggest a link between body mass, abundance, and behavioural dominance in hummingbirds. Our findings indicate the existence of a body mass range associated with the capacity of hummingbird species to be plentiful, behaviourally dominant, or to show both traits. The mechanisms behind these relationships are still unclear; however, our results provide support for the hypothesis that body mass is a supertrait that explains abundance and behavioural dominance in hummingbirds.