Blood and intestinal parasitism in Darwin's finches: negative and positive findings

Darwin’s finches are an iconic bird group that has transformed our perception of evolutionary dynamics in wild populations. Surprisingly, the parasites and diseases of these finches are virtually unstudied. This study simultaneously investigates blood and intestinal parasitism in Darwin’s Small Ground Finch Geospiza fuliginosa and intestinal parasitism in the Medium Ground FinchGeospiza fortis. We sampled 127 adults for blood parasites and 22 nestlings for blood and intestinal parasites across three islands, Santa Cruz, Isabela, and Floreana, in the Galapagos Archipelago. We found no evidence of blood parasites in G. fuliginosa and no evidence of intestinal parasitism in G. fortis. On Floreana, one G. fuliginosa nestling was identified with an intestinal parasite of the genus Isospora, which is the first record for this island.