State Epidemic Threatens Endangered Waterfowl
Protecting Hawaii’s wetlands and endangered water birds from modern development and invasive species has always been a concern for state wildlife departments. However, according to the Hawaii Division of Forestry and Wildlife (DOFAW), the leading threat to Hawaii’s native and migrant waterfowl species lies beneath the surface, in a toxin causing epidemic losses on Molokai and throughout the state.
Avian botulism outbreaks are the number one killer of waterfowl, according to DOFAW wildlife biologist Norma Creps. It is extremely important that wetland and wildlife management understands what avian botulism is and how to stop it from spreading because we have a lot of important migratory species and they can all be affected by it, she said.
“One Sunday afternoon, I got a phone call [about a dead Hawaiian Coot],” said Molokai water bird researcher Arleone Dibben-Young at an avian botulism response workshop last Tuesday. “The next morning, the birds started to die and over three days we lost 188 coots.”
What is Botulism?
Avian botulism is a disease caused by a natural toxin triggered from active bacterium, Clostridium botulinum, in freshwater and marine environments, according to the Hawaii Wildlife Center. When bird species consume wetland insects infected with the type C botulism toxin, they will go into respiratory and musculoskeletal paralysis, losing bodily and muscle functions, resulting in death after several hours if not treated quickly.
This specific type C toxin does not affect humans and is specific to water birds, said Linda Elliot, President of the Hawaii Wildlife Center. Common affected species include the Hawaiian Black-necked Stilt, Hawaiian Coot, Hawaiian Gallinule, and Hawaiian Duck, which are all listed as endangered.
Fly larvae feed on the toxic decaying bird and another bird will consume them, repeating and intensifying the cycle.
“When one carcass can produce thousands of maggots and just one maggot can kill a bird in a short period of time, it can cause a serious avian botulism outbreak,” said Elliott.
And it has.
Botulism on Molokai
All of Molokai’s outbreaks originated from the 1997 county-constructed Ohiapilo Pond Bird Sanctuary located two miles west of Kaunakakai, according to Dibben-Young. After rainfall, fish from the site’s canals can disperse into the ponds. However, because the ponds are designed to dry out annually, the fish die and can act as a gateway for the bacteria to grow, triggering the island’s first recorded botulism outbreak in 2002.
The disease spread in 2003 and sites affected by avian botulism today include the Kualapu`u wastewater oxidation ponds, Kualapu`u reservoir, the Kaunakakai reclamation facility, the Koheo wetland, and the Kaunakakai stream behind the yacht club.
Since then, Dibben-Young has gathered a group of volunteers each year to manage and minimize botulism impacts on populations by picking up carcasses before the disease has the chance to spread.
“In 2006, we collected 47,536 [dead] fish in May and 16,059 in June,” said Dibben-Young. “It took 37 days and 808 man-hours—that is an incredible amount of work, but we had no bird loses.”
In a series of avian botulism outbreaks recorded by the Hawaii Wetland Monitor, 500 birds were lost from December 2011 to April 2012 on Kauai, Maui, and Lanai. Eighty percent had been listed as endangered species.
“There was a lack of a coordinated effort to respond to that outbreak, a lack of communication, and hundreds of endangered water birds died,” said Creps. “That was the impetus for me and my office to go out and try to do [avian botulism response] training statewide.”
What’s Being Done
After the 2011 outbreak, DOFAW was awarded a National Wildlife Health grant and partnered with the Hawaii Wildlife Center to conduct a series of workshops on all the main islands. Their main objective was to create a network of wetland owners, wildlife staff and citizens who could assist and communicate with resources on and off-island in the event of an outbreak. The workshop held on Molokai last week was their last stop on their state tour.
Twelve workshop participants learned about how to identify the symptoms, follow management and mitigation processes, practice live bird transportation techniques to rehabilitation facilities, and send timely carcass submissions to labs for research.
“I see this as an extension of our education and to recognize the things that put the wetlands and the animal life in danger,” said workshop participant and cultural and environmental educator Penny Martin. “If we learn about it, we can act on it and that’s the next step for caring about our wetlands.”
Forecasting Future Botulism Outbreaks
With possible high tides and fish growing large enough to breach the canal wall into the pond at Ohiapilo Pond Bird Sanctuary, Dibben-Young said she believes this next year will be a concern. She expects another major outbreak with thousands of dead fish that will need to be picked up.
Although she’s burned out nearly all of her volunteers, she said it’s important to manage botulism hot spots to prevent its easy spread to other wetlands on other islands.
“If botulism can take up to four hours to infect a bird, it only takes Hawaiian Stilts an hour and fifteen minutes to fly to the Kilauea Point National Wildlife Refuge on Kauai and 45 minutes to fly to the Lanai wastewater facility,” she said.
To get more helping hands out to volunteer for wetland projects, Martin suggested to DOFAW representatives that they inform the public and provide a connection as to why the native and migratory waterfowl are significant to Hawaiian culture.
“It’s a bigger question of ‘do we need nature?’ Where do we fit into it?” said DOFAW wildlife biologist Fern Duvall. “That’s why botulism is important to humans because it’s taking away things that are already rare…and does that rob Hawaiian culture? I’d say yes.”
To find out ways to volunteer and help conserve Molokai’s wetlands and waterfowl, contact Arleone Dibben-Young at firstname.lastname@example.org.