Experts search for solutions to control the invasive avian parasite, Philornis downsi, on the Galapagos Islands

Specialists from Ecuador, USA, France, Spain, Australia, Trinidad, Austria, and Argentina came together last week to develop an action plan for the control of Philornis downsi, an invasive parasitic fly that is attacking at least 17 species of birds on the Galapagos Islands, including endangered species.

Funded in part by Galapagos Conservancy, this workshop was hosted by the Galapagos National Park Service and the Charles Darwin Foundation and took place from January 31 through February 3, 2012 in Puerto Ayora, Santa Cruz Island, Galapagos Islands.

Many iconic Galapagos bird species, including the world-famous Darwin’s finches and the very rare Mangrove Finch, Floreana Mockingbird, and Medium Tree Finch, are currently at serious risk due to the presence of this non-native fly, whose larvae cause very high mortality among nestlings. In addition to direct nestling mortality (sometimes up to 100% of fledglings in a nest die from parasitism), studies have confirmed that surviving nestlings often have deformed beaks, reduced growth rates, and anemia.

The high mortality and long-term impacts on finch populations from this fly species are of grave conservation concern, especially for endangered and declining species like the Mangrove Finch and Floreana Mockingbird.

Currently there are no techniques available to mitigate the impacts of P. downsi on Galapagos birds. Substantial gaps in the understanding of the life history and ecology of P. downsi has hindered the development of methods to reduce fly numbers.

This workshop, made possible with the support of Galapagos Conservancy, Galapagos Conservation Trust, and Durrell Wildlife Conservation Trust, provided the opportunity to share information and identify gaps in the knowledge about P. downsi and discuss the feasibility of using different control methods, such as traps with attractants, sterile insect techniques, and biological control.

Additionally, the workshop helped Galapagos conservation organizations raise awareness about P. downsi at the local and international level. In spite of the high number of species severely affected by P. downsi, this fly has a very low profile.

Following a day of talks that were open to the public, participants were divided into four groups to discuss and develop action plans for specific themes related to the protection of endemic birds and the control of P. downsi. Key outputs of the workshop included:

1. the development of a program to monitor land birds
2. an action plan for the immediate and long-term protection of threatened bird species with a detailed plan focusing on reversing the decline of endemic bird species in Los Gemelos on Santa Cruz Island (identified as the highest priority habitat for restoration and protection)
3. an action plan for the immediate mitigation of P. downsi on the critically endangered Mangrove Finch (Camarhynchus heliobates) population
4. a plan detailing experiments and observations necessary to fill crucial gaps in the knowledge about the ecology of P. downsi
5. a five year research plan to develop novel methods for the control of P. downsi across the archipelago.

Experts left the workshop feeling energized and ready to work; however, funding is urgently needed to put some of these plans into action.

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