Conservation and ecology of Darwin’s finches

Due to its geographic isolation the Galapagos Archipelago is a fragile ecosystem that is facing a increasing number of threats. A systematic census of Darwin’s finches over the last decade revealed a dramatic decline of Darwin’s tree finches (Dvorak et al. 2012). We are currently investigating reasons for this decline and our research has already revealed that an introduced dipterian parasite (Philornis downsi) plays a prominent role in the decline of the Darwin’s finches. (Cimadom et al. 2014) We accidentally discovered this hitherto unknown dipterian bird parasite on Santa Cruz Island. The first larval stage  usually develop in the chicks’ nostrils, whereas the second and third larval stages  live in the bottom layer of the nest and suck blood from the nestlings during the night. This obligate bird parasite was probably introduced to the Galapagos Islands during the last century and is now seen as one of the biggest threats to the Galapagos avifauna. In an experimental study, we could demonstrate that Philornis infestation has a strong effect on nestling mortality in Darwin’s finches (Fessl et al. 2006).  

The topic of one ongoing PhD project conducted by Arno Cimadom is to investigate the influence of parasitism by Philornis on the population development of two declining Darwin’s tree finches and to test whether there is an interaction between parasitism and other environmental stressors (habitat and climate change) with an experimental approach. In cooperation with the Charles Darwin Research Station, the Galapagos National Park and the International Atomic Agency, the Universities of Syracus and the University of  Minnesota and the Department of Microbiology and Ecosystem Science, we want to investigate several aspects of the life cycle of Philornis downsi, which is a precondition to develop control measures for this invasive parasite.

Researcher: Sabine Tebbich