Vampire Finches - giving sanguivory a try
Although dramatic, “vampire finch” is not a terribly accurate name for this bird, which is also known as the sharp-beaked ground finch. Basically, the vampire tag is questionable because, unlike the other sanguivores mentioned thus far, Geospiza difficilis is not an obligate blood feeder (i.e., it isn't dependent on obtaining blood on a regular basis).
The birds merit mention, however, because they appear to be giving part-time blood feeding a serious shot. In that regard, vampire finches occasionally supplement their normal diet of small seeds and flower nectar, by eating eggs and by pecking at the wings, body and tail regions of another Galápagos Islands resident – the blue-footed booby (Sula nebouxi). Once Geospiza difficilis has inflicted a small wound with its beak, it begins sipping the booby’s blood, hopping out of the way if the larger bird gets annoyed. The finches feed in this manner for several minutes, giving way to other individuals who line up, waiting their turn like customers at a deli counter.
The birds merit mention, however, because they appear to be giving part-time blood feeding a serious shot. In that regard, vampire finches occasionally supplement their normal diet of small seeds and flower nectar, by eating eggs and by pecking at the wings, body and tail regions of another Galápagos Islands resident – the blue-footed booby (Sula nebouxi). Once Geospiza difficilis has inflicted a small wound with its beak, it begins sipping the booby’s blood, hopping out of the way if the larger bird gets annoyed. The finches feed in this manner for several minutes, giving way to other individuals who line up, waiting their turn like customers at a deli counter.
Vampire Finches
Vampire finches live on two of the the Galapagos Islands (Darwin and Wolf). They use their sharp beaks to peck small wounds on larger birds. Then they sip the blood that flows from those wounds. There is no evidence that their saliva contains an anticoagulant - although that would certainly be an interesting study.