Good Samaritans are really vampires

RED-BILLED oxpeckers were once thought to help large African mammals by
eating the ticks on their hides, although it had been suspected that the
relationship is more sinister. So Paul Weeks of Cambridge University chased off
oxpeckers that tried to land on one group of oxen in Zimbabwe, but allowed the
birds to settle on another group. After a month, both groups had just as many
ticks (Behavioral Ecology, vol 11, p 154). Instead of helping the
animals, the birds spent much of their time picking at the oxen’s wounds. “They
return to the site of the wound and…