Climate change is altering the frequency and intensity of extreme climatic events such as tropical cyclones, raising concerns about ecological stability under such disturbances. This study examined how functional richness and redundancy influence the stability of two key ecological functions—insect predation and seed dispersal—in forest bird communities with contrasting histories of cyclone exposure. Using total biomass of insectivores and frugivores as functional indicators, we found that the stability of insect predation increased with redundancy in effect traits, whereas the stability of seed dispersal was associated with redundancy in both effect and response traits. In forests frequently exposed to cyclones, both functional groups occupied a smaller overall trait space, while frugivores showed greater trait similarity among individuals. These results suggest that stability in insect predation and seed dispersal under cyclone disturbances largely stems from the abundance of species performing similar functional roles. High cyclone frequency appears to exclude species with extreme traits and concentrate functional space around a few dominant species with convergent traits. Because such convergence buffers cyclone impacts, the loss of even a few redundant species could increase functional uniqueness and, consequently, reduce the functional stability of forest bird communities.