Monday, 13 July 2015

Creature 286: Geospiza difficilis

Run! They have acquired a taste for blood.

Geospiza difficilis is one of Darwin's Galapagos Island finches and it it commonly called the sharp beaked ground finch.

As its name suggests it has a rather sharp beak. Its diet is usually fairly  typical for a bird, comprising of arthropods and some from various plants, but there is one subspecies which has developed a rather disturbing habit.

The subspecies Geospiza difficilis septentrionalis will sometimes feed off the blood of larger birds, usually Boobies*. Their sharp beaks peck holes in their skin and they feed on the blood which comes out. Whats is even stranger is that the boobies don't seem to resist. Some Ornithologists believe that this behavior must have evolved from the finches picking small arthropods from the feathers of the boobies and occasionally accidentally breaking the skin. The boobies don't resist because historically they would have benefited from the finch picking them clean of parasites.

*Sidenote: before you get carried away by the fact that there are birds called Boobies, I should mention that there is also a group of birds called tits which includes the great tits. Both these bird groups will have posts of their own on this blog eventually.

Geospiza difficilis is native to the Galapogus Islands.

Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Order: Passeriformes
Family: Thraupidae
Genus: Geospiza
Species: Geospiza difficilis

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