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Cornell Postdoctoral Fellow Helping to Save Hawai‘i’s Native Birds

Iʻiwi, Drepanis coccinea © Katherine McClure
Iʻiwi (Drepanis coccinea), once common in native Hawaiian forests across the state, was protected under the Endangered Species Act as a Threatened species in 2017. Iʻiwi suffer high rates of mortality when infected, with the bite of a single malaria-infected mosquito sufficient to kill them. © Katherine McClure

Dr. Katherine McClure, a quantitative disease ecologist, has been working with the multi-agency consortium Birds, Not Mosquitoes as a Cornell Atkinson Center for Sustainability postdoctoral fellow with the Cornell Wildlife Health Center to develop and evaluate incompatible insect technique (IIT) release strategies to help save Hawai‘i’s native bird populations from avian malaria, an alien invasive disease.

A portrait of Katherine McClure with a bird in her hands
Katherine in the field, savoring her time away from the computer. Photo provided.

Hawaiian honeycreepers are a spectacular endemic bird taxa currently threatened by avian malaria, an introduced infectious disease transmitted by the invasive southern house mosquito (Culex quinquefasciatus). As the climate warms, disease-transmitting mosquitoes are invading the last strongholds for birds in upper elevation forests in Hawai‘i, once too cool for mosquito or malaria development. In higher elevation forests on the island of Kaua‘i, for example, six of seven native bird species have recently experienced range-wide collapses that coincide with sharp increases in mosquito abundance and malaria prevalence in native birds. It’s important to note that eight of the twenty-three U.S. species just declared officially extinct by the USFWS are Hawaiian birds.

To save these highly imperiled native birds, the seemingly intractable problem of mosquito-borne disease transmission must be addressed at a landscape scale across the Hawaiian Islands. Fortunately, recent developments in novel mosquito control techniques—and unique applications for wildlife conservation—may hold the key to addressing Hawai‘i’s avian conservation crisis.

ʻAkiapōlāʻau, Hemignathus wilsoni © Katherine McClure
​ʻAkiapōlāʻau (Hemignathus wilsoni) is an endangered Hawaiʻi honeycreeper species endemic to Hawaiʻi Island that could benefit from novel mosquito control. © Katherine McClure

Birds, Not Mosquitoes is a consortium of federal, state, university, and non-profit partners, including the American Bird Conservancy, that is advancing an IIT program using Wolbachia, a naturally-occurring, non-genetically modified, endosymbiotic bacteria, to suppress mosquito populations in native forest bird habitat in Hawai‘i. Through repeated mass releases of male Wolbachia-transinfected southern house mosquitoes (thus rendered reproductively incompatible with wild females), population-level birth control for mosquitoes causes their populations to crash and eliminates local avian malaria transmission. Birds, Not Mosquitoes partners are working to further develop the research tools, operational capacity, funding sources, permitting, and community engagement strategies required to advance this crucial conservation action in Hawai‘i.

Working closely with project partners, Katherine used computational models to simulate population dynamics as related to a range of scenarios for mass releases of mosquitoes to estimate optimal release parameters. Results suggest that frequent applications at sufficiently high numbers will significantly reduce mosquito populations across realistic gradients of temperature. These models support operational and budgetary planning for Wolbachia-transinfected mosquito releases, and are a key tool for testing release strategies in advance of on-the-ground mosquito control efforts.

Kauai © Liz Abraham
Kauai, an island where Wolbachia-transinfected mosquito releases are planned to occur, is home to several bird species that sit on the brink of extinction. © Liz Abraham

When she began her fellowship at the Cornell Atkinson Center for Sustainability and the Cornell Wildlife Health Center, Katherine’s research was squarely focused on the numbers game of monitoring and controlling mosquito populations. But she quickly discovered that there are many other skills required for effective collaboration to achieve real-world conservation impact beyond traditional academic skills and mindsets. Katherine participated in the Cornell Atkinson Center for Sustainability and Environmental Defense Fund’s Sustainability Leadership program. Through excellent workshops and trainings in interdisciplinary collaboration, science communication, and career development, she is now inspired by a collaborative vision of leadership that prioritizes listening and respect.

“The Cornell Atkinson postdoctoral fellowship program, along with fantastic mentorship at the Cornell Wildlife Health Center, helped provide me with a new set of tools to help translate ideas and techniques from public health into effective wildlife conservation action,” said Katherine.

Hakalau Stream in Hakalau National Wildlife Refuge © Katherine McClure
Hakalau Stream in Hakalau National Wildlife Refuge may provide routes for mosquito invasion into the refuge. © Katherine McClure

Katherine recently completed her Cornell postdoctoral fellowship and plans to continue to actively implement these skills in her new position as a quantitative ecologist with the Hawaiʻi Cooperative Studies Unit at the University of Hawaiʻi at Hilo and the USGS Pacific Island Ecosystem Research Center on Hawaiʻi Island. Her work there will focus on the analysis of mosquito and avian malaria data to inform avian conservation efforts and to predict mosquito invasion probability via streams into high elevation forests in Hakalau National Wildlife Refuge under climate change scenarios.

“We couldn’t be more proud in terms of all that Dr. McClure has accomplished during her fellowship,” notes Professor Steve Osofsky, her faculty mentor and director of the Cornell Wildlife Health Center. “We look forward to ongoing collaborative opportunities to secure a future for wild nature, with Katherine as well as with colleagues at Cornell Atkinson.”

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