Temporal variation of daily activity on pollinator and frugivorous birds simultaneously interacting with a specialized mistletoe

Different interactions occur simultaneously, affecting the ecological and evolutionary outcome of the species within a community. Mutualisms are particularly relevant for maintaining and generating biodiversity, and among them, pollination and seed dispersal play a central role in plant regeneration. Due to its parasitic life-form and ecological specialization, mistletoes provide a good study system to assess the effects of simultaneous interactions in the wild. We used the highly specialized mistletoe Tristerix aphyllus, its pollinator (the hummingbird Sephanoides sephaniodes), and its seed disperser (the mockingbird Mimus thenca) to assess their daily activity patterns during a flowering-fruiting overlap period. Given that both bird species are diurnal, we expect them to have different visitation times despite using different resources. Using camera traps, we found that both species have different daily activity patterns (overlap index Δ ^ ₄ = 0.83, p < 0.001). While M. thenca had a narrow activity period early in the morning, S. sephaniodes had a wider activity range. We also found that the temporal variation of those activity patterns might be related to resource availability, as the number of flowers has decreased (F_2,52 = 13.85, p < 0.001) over time, while the number of ripe fruits has increased (F_2,52 = 5.16, p = 0.009) over time. Our results show that having different activity patterns could be a coexistence mechanism among bird species interacting with the same plant but exploiting different resources. Thus, taking activity patterns into account can provide a better understanding of ecological processes involving multiple interactions taking place simultaneously in the community.