Nest predation is the dominant cause of nest failure in the tropics. However, our knowledge about tropical nest predator identity and community structure is still quite limited. On 9 January 2019, we video-recorded an Olive Sunbird (Cyanomitra olivacea) removing and flying off with an egg from an African Paradise Flycatcher (Terpsiphone viridis) nest in the East Usambara Mountains, Tanzania. This observation is surprising because the Olive Sunbird is a specialized nectarivore. Nectar, however, is a poor source of nitrogen and cannot meet the protein requirements for nectarivores. We hypothesize that bird eggs are a potential source of protein for selected long-billed sunbird species—species that can grasp and handle small bird eggs. Our observation of nest predation by an Olive Sunbird adds a heretofore unknown behavior to nectarivores in general and to sunbirds specifically.