Conservation of Small Landbirds
The small landbirds of Galapagos are famous worldwide for providing important clues about the processes of evolution. They are also essential to Galapagos ecosystems through their contribution to plant pollination, seed dispersal and many other ecological processes. In a race against time, Charles Darwin Foundation scientists and their collaborators are working hard to find ways to ensure that they are protected from the Avian Vampire Fly, Philornis downsi, an invasive parasitic fly that is threatening nearly every species of small landbird in the Galapagos Islands. The larvae of the Avian Vampire Fly feed on the blood of newly hatched birds often resulting in unsustainably high levels of mortality. This fly has been implicated in the rapid population declines of six species of the iconic Darwin’s finches, including the critically endangered Mangrove Finch. The impending threat that this fly poses to endemic landbirds has made this a conservation priority for the Galapagos National Park Directorate.
Our robust team of entomologists, ornithologists, and restoration specialists are working to develop holistic conservation plans for at-risk bird species using experimental and innovative approaches. As a temporary measure to protect the most vulnerable bird species, we are investigating environmentally friendly techniques to reduce the impact of the Avian Vampire Fly in bird nests. So far, injecting insecticides into the base of nests, where the blood-feeding larvae reside, has increased fledgling survival in situ in four threatened bird species, including the Little Vermillion Flycatcher (Fig. 1). For the hard-to-reach nests we are evaluating the use of the self-fumigation technique where birds help us do the work by taking material back to the nest which is impregnated with natural repellents or minimum-risk insecticides. Additionally, we are studying the potential of attractant odours from fermenting fruit, birds and flies (pheromones), as lures in fly trapping programs.
In parallel, we are working on the development of larger scale, sustainable solutions that can significantly and permanently reduce or eliminate populations of P. downsi. The most promising of these is biological control, which involves the importation of a natural enemy that selectively targets the fly. We have just obtained government approval to conduct the last-needed studies on a parasitic wasp that seems to be a specialist natural enemy of P. downsi and in 2021 plan to import the wasp to Galapagos to test it against Galapagos insects. Biological control has been used previously and successfully in the Galapagos Islands by our team and is considered a safe and effective option for controlling environmental pests in hard-to-reach locations.
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