Flowers of Aphelandra sinclairiana have features of flowers pollinated by hermit humming-birds (long corollas) and of those pollinated by territorial humming-birds (dilute nectar, clustered distribution). Flowers in large clumps at the peak of the blooming season were pollinated by two territorial humming-birds, but at the end of the season or in isolated plants the main avian pollinator was the non-territorial hermit Phaethornis superciliosus. Visits by avian nectar thieves were more frequent at high flower densities. The reproductive output of inflorescences was similar at different levels of flower aggregation. Aphelandra flowers in large clumps could exchange pollen with extraterritorial plants because territorial humming-birds did not completely exclude pollinating hermits. The commonest nectar thief at high flower aggregations was the passerine Vermivora peregrina, the second most common nectar thief was the hermit Phaethornis longuemareus.
