Owing to the availability of different food types, the sharp-beaked ground-finch's diet varies between the high islands and the low islands (2). Although populations on the low, dry islands mainly feed on seeds (7), they are also known to augment their diet from several unusual sources. It is on the small and remote islands of Wolf and Darwin that this species frequently drinks the blood of large seabirds, especially boobies (Sula spp.). Alighting on the backs of the larger birds, it pecks at the feather shafts with its long, pointed beak until blood begins to flow (3) (4) (5) (6) (8). In addition, it likes to feed on the eggs of seabirds, which it cracks open against rocks (5) (8), or alternatively forage for nectar from Opuntia catci (Wolf and Darwin) and the small flowers of Waltheria ovata (Genovesa) (6). In contrast, while populations at high elevations also take seeds, they concentrate most of their foraging efforts in areas of deep ground litter where invertebrate prey is abundant (7).