This just in from New Scientist:

A species of moth drinks tears from the eyes of sleeping birds using a fearsome proboscis shaped like a harpoon, scientists have revealed. The new discovery – spied in Madagascar – is the first time moths have been seen feeding on the tears of birds.

Roland Hilgartner at the German Primate Centre in Göttingen, Germany, and Mamisolo Raoilison Hilgartner at the University of Antananarivo in Madagascar, witnessed the apparently unique sight in the island state’s Kirindy forest.

Tear-feeding moths and butterflies are known to exist elsewhere in Africa, Asia and South America, but they mainly feed on large, placid animals, such as deer, antelope or crocodiles, which cannot readily brush them away. But there are no such large animals on Madagascar. The main mammals – lemurs and mongoose – have paws capable of shooing the moths. Birds can fly away.

But not when they are sleeping. The Madagascan moths were observed on the necks of sleeping magpie robins and Newtonia birds, with the tip of their proboscises inserted under the bird’s eyelid, drinking avidly (scroll down for images). This was during the wet season, so the scientists think the insects wanted salt, as the local soils are low in sodium.

You can read the rest of the story here (be warned, there's a photo of the moth in action).