Biotic interactions influence evolutionary pathways, impacting diversification positively and negatively. Here, we examine the coevolutionary dynamics between frugivorous diets and carotenoid-dependent plumage coloration in passerine birds— a highly diverse order in which nearly half of species exhibit carotenoids in their plumage. Plumage coloration is crucial for species recognition and mate choice. As birds cannot synthesize carotenoids, they must obtain them from the diet. We analyze data from 90% of passerines and explore correlations between frugivory, a key carotenoid source, plumage coloration, and diversification rates.The data used in our study includes binary classification of passerines based on whether they present carotenoid-dependent plumage coloration or not and whether fruit compose 50% or more of the diet, also codified as a binary trait. All data come from published sources. Our Bayesian analysis reveals a strong evolutionary correlation between frugivory and the presence of carotenoid plumage coloration. However, Bayesian state-dependent speciation and extinction models (SSE) showed that neither frugivory nor carotenoid coloration independently correlate with heightened diversification. Results are unchanged when we analyze the combination of both traits, challenging the conventional assumption of increased speciation driven by frugivory in species with carotenoid-dependent plumage coloration. These findings underscore the complexity of trait interactions in shaping evolutionary trajectories and the importance of hidden states in modeling diversification.