Bye Bye Birdie: The Disappearing Avifauna of Hawaiʻi

FEB 29, 2016    by LAUREN R. KAISER

Critically Endangered ʻAkekeʻe (Loxops caeruleirostris) Photo Credit: Jim Denny

As an isolated island archipelago in the middle of the Pacific Ocean, the Hawaiian Islands have become home to many endemic species found nowhere else in the world. Hawaiʻi provided a unique place for ecological divergence, leading to the evolution of the islands’ expansive and impressive native avifauna. The forest birds in particular are biologically significant to the complex and fragile forest ecosystems of Hawaiʻi. These birds also hold a prominent position in Native Hawaiian culture as the feathers are considered some of the most valuable things to own and are important to the ancient art of Hawaiian feather artisans.

Threatened Iʻiwi Honeycreeper (Vestiaria coccinea) Photo Credit: Jack Jeffery

Sadly, less than half of the original native Hawaiian forest bird species exist in the wild today. Historical human impacts that led to the decline of many forest birds included the introduction of new species, habitat modification, and avian diseases. More recent human-caused effects stem from ongoing climate change in the region. Warming, for example, has increased the range of non-native mosquito vectors carrying avian malaria into upper elevations, leading to even higher infection rates. Forest birds are being restricted to the last narrow bands of high-elevation forest refugias as the climatic limits of these mosquitos decline over time. Future climatic changes will most likely continue to affect the survivorship of these already endangered endemic Hawaiian forest birds.

Recent research projects that Hawaiian forest birds may lose at least half, if not all, of their current habitat range by the end of the century. Using innovative modeling methods to determine species distribution ranges, scientists projected future shifts in forest bird habitats linked to the coupled impacts of climate change and avian malaria. As warming continues, mosquitos carrying avian malaria are projected to be able to spread into high-elevation forest regions, leaving no uninfected habitat area left for the native forest birds. This collaborative study by the Pacific Islands Climate Change Cooperative (PICCC) and USGS Pacific Island Ecosystems Research Center (PIERC) highlighted the need for continued conservations and restoration of critical habitat areas and suggested that these efforts alone may not be enough to preserve these forest bird populations, calling for novel methods to be considered as management options. This is not to say that there is no hope for the future of these native bird species, only that the researchers said the time to act is now.

Some conservation methods already have been enacted to help preserve the livelihood of these native forest birds in the future. For example, different conservation groups aim to preserve habitats for these forest birds by removing mosquito larvae from streams, managing invasive ungulates, and limiting access of other invasive species and predators to certain areas. Also, the San Diego Zoo Global in conjunction with local Hawaiʻi based partners has begun captive breeding programs for certain at-risk forest bird species. These native species include the ʻAkekeʻe, ʻAkikiki, Maui Parrotbill, Palila, and Puaiohi, along with other native avifauna such as the Nene and ʻAlala. These efforts are important to increase the survivorship of rare species and need to be continued as current conservation strategies. However, while all these projects are helping to maintain current species populations, they alone may not be enough to overcome the challenges presented by climate change.

Extinct Hawaiʻi ʻŌʻō (Moho nobilis) Image Credit: Marian Berger

In light of these serious and ever-increasing threats to the endemic forest birds of Hawaiʻi, there has been a call for additional and more advanced action within the conservation community. Viable adaptation and management strategies will likely include a combination of conservation methods, both conventional and unconventional, such as habitat protection coupled with genetic modifications of birds to be immune to avian malaria or captive breeding in conjunction with reintroduction or translocation. A single panacea can hardly be expected to resolve such an intricate and multifaceted problem. This joint research by PICCC and USGS calls for such additional and novel conservation actions as the reality is that sustainable and scientifically based, long-term solutions need to be implemented to avoid possible range collapses and more avian extinctions in the future.

For more information and results, check out this PICCC story map here.

Lauren R. Kaiser is a Researcher for the USGS Pacific Island Ecosystems Research Center (PIERC) at the University of Hawai’i System.

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