Predators with a taste for blood abound on the remote Galapagos Islands…

Meet the Vampire Ground Finch

19 different species of finches can be found on the Galapagos Islands. Observations of their various beak shapes, specialized for different diets and purposes, helped Charles Darwin develop the theory of evolution. One species I do not recall learning about in Biology class, however, is the vampire ground finch (Geospiza septentrionalis), which can be found on the remote Darwin and Wolf Islands, not thought to be visited by Darwin. Food is not plentiful on these islands during the dry season. As the name implies, these finches developed a taste for the blood of blue-footed as well as Nazca boobies that nest on the islands. Scientists think their strange diet might have evolved when some vampire ground finches consumed ectoparasites from the feathers of the boobies and accidentally tasted blood. The gut microbiome of these finches is uniquely suited to process their blood meal with the help of similar gut microbes as carnivorous reptiles and birds. Apart from occasionally dining on blood meals, their main diet is similar to other finches and includes seeds, nectar, insects, as well as guano and booby eggs.

Meet the Avian Vampire Fly

The avian vampire fly, Philornis downsi, is native to South America but can be found on the Galapagos Islands. Larval avian vampire flies infest bird nests where they target the beak of developing nestlings and feed on their blood, tissue, and keratin. Such infestations widen the nestling’s nasal openings and deform their beak. In fact, up to 34% of adult birds sampled on the islands showed signs of wider nasal openings. By altering their beak structure, the larvae may impact what and how the birds eat throughout their life. The Galapagos Conservancy has been developing strategies to control this pest to help protect the island’s precious bird populations.

Sources:

YouTube

AJ Michel, LM Ward, SK Goffredi, KS Dawson, DT Baldassarre, A Brener, KM Gotanda, JE McCormack, SW Mullin, A O’Neill, GS Tender, JAC Uy, K Yu, VJ Orphan, JA Chaves. The gut of the finch: Uniqueness of the gut microbiome of the Galapagos vampire finch. Microbiome. 6:167, 2018.

S Kleindorfer, D Colombelli-Negrel, LK Common, JA O’Connor, KJ Peters, AC Katsis, RY Dudaniec, FJ Sulloway, NM Adreani. Functional traits and foraging behavior: Avian vampire fly larvae change the beak and fitness of the Darwin’s finch hosts. Functional Ecology. 36(7): 1806-1817, 2022.

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Categories: Diet and Exercise, Extreme Animals, Nature's Solutions

Tags: animals, birds, blood, Darwin, finch, flies, Galapagos, nature, vampire