Pollen transfer on birds' tongues

Plants are adapted for pollination by birds in diverse and intricate ways. Here I describe an extraordinary example of these adaptations. The flowers of Microloma sagittatum, a member of the milkweed family, clip parcels of pollen precisely onto the tongues of sunbirds. The pollen parcels are carried inside the bird's mouth to the next flower where they are detached mechanically. This is, to the best of my knowledge, the first evidence for pollen transfer on the tongues of birds, a phenomenon that might be more widespread.