A chorus of songs from three rare native forest birds was heard last month at lower elevations of Hakalau Forest National Wildlife Refuge for the first time in 30 years. This unexpected detection of the Hawaii creeper, akepa and akiapolaau
A chorus of songs from three rare native forest birds was heard last month at lower elevations of Hakalau Forest National Wildlife Refuge for the first time in 30 years. This unexpected detection of the Hawaii creeper, akepa and akiapolaau is welcome news to those hoping to save the endangered birds from extinction.
“Detecting these endangered forest bird species is encouraging because of the serious challenges these birds face, including the expansion of disease due to global climate change, competition with introduced non-native birds, introduced predators and habitat destruction from feral ungulates,” said Steve Kendall, a wildlife biologist for the U.S. Fish and Wildlife Service. “These endangered species were not detected when U.S. Geological Survey biologists last visited this remote location.”
The rediscovery happened May 22, when USFWS and U.S. Geological Survey scientists spent 11 hours trekking four miles through rugged terrain to a remote area in the lower elevations of Hakalau Forest NWR. They were doing a project that studied the potential impact of climate change on introduced mosquito-transmitted diseases, such as avian malaria and pox virus. They were not expecting to detect three of Hawaii Island’s rarest forest birds, all of which are “at risk, very vulnerable and have a low population,” Kendall said.
Hawaii’s native birds are believed to be highly susceptible to mosquito-transmitted diseases, limiting their distribution to the cooler, higher elevations of the refuge. While the new observations “do not change the status of the birds, which are in dire straits,” the finding significantly extends the current known range of the species at the refuge and will hopefully prompt further scientific investigations, Kendall said.
An annual bird population census is conducted at Hakalau Forest NWR, usually in the spring, but not at lower elevations, he added.
Because of active habitat management and restoration, Hakalau Forest NWR is one of few Hawaii Island places where populations of native forest birds are increasing or at least stable. Kendall did not know the population totals to date. Ongoing studies at the refuge on avian disease, forest bird demographics and food resources, as well as feral pig control may shed some light on whether these endangered forest birds are holding their own or recovering at lower elevations.
USFWS Pacific Region Director Robyn Thorson said the findings reinforce the importance of monitoring to detect changes in environmental conditions, habitat and associated wildlife populations.
“Hawaii’s native birds face multiple threats from habitat destruction, invasive species, introduced diseases and climate change, with many already having been driven to extinction,” USGS Director Marcia McNutt said. “The observation of three endangered species possibly expanding their range in a wildlife refuge gives us hope that with some care, the road to extinction need not be a one-way street.”
USGS Pacific Island Ecosystems Research Center and USFWS Hakalau Forest NWR scientists heard the Hawaii creeper and Hawaii akepa at 4,200-foot elevation near Awehi Stream, within a mile of where they were last observed by USFWS biologists during the 1977 Hawaii Forest Bird Survey. Most important were visual and aural detections of at least one endangered akiapolaau at 4,200 feet, which is 1,000 feet lower in elevation from previous sightings in the 1970s.
Extensive surveys of Hawaii Island forest habitats in the late 1970s and early 1980s showed the best remaining habitats and largest native bird populations were in the high-elevation rainforests on Mauna Kea’s eastern slopes. This led to the establishment of Hakalau Forest NWR in 1985 to protect and manage endangered forest birds and their habitats. It’s the only national wildlife refuge dedicated to conservation and restoration of Hawaiian forest birds.
An overall integrated conservation strategy, which includes research, habitat management, ecological restoration and public education, is key to helping Hawaii’s native forest birds. The public can help by getting involved with Hakalau Forest NWR’s extensive volunteer program, assisting in the recovery of degraded ecosystems and helping establish healthy habitats. Besides voluntary brute-force labor, Hawaii Island residents can provide ongoing critical support for restoration programs and scientific endeavors at the refuge, which has a tiny staff, modest operating budget and myriad of responsibilities, Kendall said.
