The COVID-19 pandemic slowed conservation work across the state, including efforts to trap and sterilize cats that eat endangered birds.

Many conservationists feared there would be a major explosion in the number of cats as a result, posing a big risk to endangered birds, marine animals and even human health.

Although there is no official count of Hawaii’s feral cat population, neither the state, Humane Society or bird conservationists reported a dramatic increase in the population. Partly because of a spike in adoptions, increased pet food donations and because Hawaii’s economy didn’t experience the same long-term impacts that forced many people to abandon their pets after the 2008 financial crisis.

But many endangered species in Hawaii are “hanging on by a thread” and even a slight increase in the feral cat population could push some species to extinction.

“Although we might not yet realize the impact the 2020 hiatus has had — I’m worried,” said Chris Farmer, the Hawaii Program Director at the American Bird Conservancy. 

An iiwi feeds on the lehua blossom of the ohia tree in Hakalua Forest Reserve on the Big Island. Feral cats pose a great risk to native bird populations. Courtesy: Bettina Arrigoni/Flickr

Conservationists in Hawaii regularly hike to remote locations and install predator-proof fences, place game cameras and install traps to protect endangered birds that haven’t evolved to evade human-introduced predators like cats.

During the pandemic Farmer said work on the Big Island has been much slower because forest crews had to travel in separate cars, helicopters and ATVs, meaning fewer people could access remote areas where these birds live. Supply chain delays made it difficult or expensive to acquire essential gear.

Farmer doesn’t doubt that predators slipped through defenses during this time, which could impact the survival of entire species.

“We’re talking about species where they’re 100 or 1,000 individuals,” he said. “These are birds on the brink of extinction and it takes the dedicated efforts of dozens of people to allow them to recover.”

Cats are one of the top predators that contribute to biodiversity loss worldwide. Cat poop spreads a dangerous parasite throughout the watershed and the Hawaii Department of Land and Natural resources considers feral and free-roaming cats a “top concern.”

A study found that in two years cats killed more than 250 native birds at Hanalei National Wildlife Refuge. Cats have contributed to the extinction of 63 species, including the Lanai Hookbill and Hawaiian Rail and have been found killing endangered seabirds in extremely remote locations.

Alex Dutcher, lead biologist and co-owner of Hallux Ecosystem Restoration, a company that manages predators like cats and rats in remote areas of Kauai, said that she’s seen first-hand how a single cat can have “devastating effects” on seabird colonies.

Hallux Ecosystem Restoration employees were considered essential workers, and much of their work is done outdoors so they were able to continue their work monitoring trail cameras and trapping and euthanizing cats that kill native birds throughout the pandemic.

Game cameras on Kauai regularly catch feral cats eating endangered birds. Conservation workers identify cats by their unique markings and set traps. Courtesy Hawaii DLNR

Dutcher and co-owner Kyle Pias both have pet cats and stress the animals they’re targeting are feral animals in remote areas, not pets.

“They’ve never seen people before,” Dutcher said. “If we did interact with a cat that showed any semblance of friendliness … we would bring it down to the Humane Society but that has not happened so far.”

Last year a single cat killed 12 Newell’s Shearwaters, or aos, a critically endangered seabird endemic to Hawaii that nests on steep mountain slopes. The bird doesn’t breed until it’s 6 or 7 years old, so the loss of a single adult is impactful.

“It was devastating,” Pias said.

Cats also kill native species indirectly by excreting a deadly parasite called toxoplasma gondii. The parasite is only able to reproduce inside of a cat’s digestive tract, making cats a definitive host.

Toxoplasma gondii is one of the top killers of the Hawaiian goose, or nene, and has been found in other species like the Hawaii crow and red-footed booby. Marine animals like the endangered Hawaiian monk seal have also been killed by the parasite.

A recent study found that more than 40% of chickens on Kauai carry toxoplasma gondii, raising alarms about the prevalence of the parasite throughout the watershed.

Toxoplasma gondii can also impact humans, and infections can cause anything from flu-like symptoms to blindness and miscarriage.

“There is a real concern about both human and wildlife health impacts based on cats living in the wild,” said David Smith, who leads DLNR’s Division of Forestry and Wildlife.

Person who declined giving their name feeds cats at Kakaako Waterfront Park on the Diamond Head end of the park.
A resident who declined to give her name feeds cats at Kakaako Waterfront Park. DLNR requests that people not feed cat colonies, especially on public lands. Cory Lum/Civil Beat/2021

The Hawaiian Humane Society hopes to decrease the feral cat population over time by trapping, sterilizing and releasing cats.

But it had to pause its trap-neuter-release program between March and June of 2020 to put in place new safety protocols and get supplies like face masks for veterinarians and volunteers.

Cats sit on wall at Kakaako Waterfront Park with Diamond Head in the background.
At one point during the pandemic, the Hawaiian Humane Society had a 300-person waitlist to foster a pet. Cory Lum/Civil Beat/2021

According to Daniel Roselle, director of community relations for the Hawaiian Humane Society, the organization sterilized about 1,500 cats in fiscal year 2020. But it’s completed more than 5,000 sterilizations in fiscal year 2021, which is even up from the 2,800 cats sterilized in 2019.

“Our spay-neuter numbers have basically doubled in fiscal year 2021,” Roselle said.

He attributes the increase to the Humane Society’s new facility and the City and County of Honolulu eliminating sterilization fees. “And there was such a demand for adoption across all islands that we were firing on all cylinders to process adoptions.”

The Humane Society also gave away 61,000 pounds of pet food, allowing many people to keep pets in their homes instead of relinquishing them to the Humane Society or releasing them in the wild.

“We were really concerned but it’s been amazing how the community has really stepped up,” Roselle said, adding that cat owners can further help out by keeping their pet indoors.

“Cats are safer and healthier living inside the home,” he said. “It’s not a question of judgment but there’s risk of disease, risk of injury from cars … and we agree with conservationists that it’s not good for the environment.”

Debating Approaches

While DLNR also stresses the importance of keeping pet cats indoors, the department and many conservationists don’t support releasing cats back into the wild after sterilization.

“We don’t think that that’s a good animal management situation,” DLNR’s Smith said, citing research that programs to trap, neuter and release animals do not decrease feral cat populations. The department also tries to discourage people from leaving food out for free-roaming cats, especially on public lands or near wildlife sanctuaries. “My motto has always been: if you want this cat, great. Take it home.”

Unlike mongooses and rats, which are rarely kept as pets and are therefore euthanized without controversy — or stray dogs, which pose a more obvious public health threat and are therefore strongly regulated — Hawaii’s feral cat populations inspire heated debate.

“This problem wasn’t created overnight and it won’t be solved overnight,” said Roselle. “While we may not all agree on the solution, we definitely agree that we need to work together.”

The Hawaiian crow, or alala, is extinct in the wild and reintroduction efforts have been unsuccessful. Courtesy: San Diego Zoo Wildlife Alliance

Conservationists point to the Lanai Cat Sanctuary as a kill-free option that protects native wildlife while providing medical care and socialization to cats. But efforts to open sanctuaries on other islands have stalled due to lack of funds and difficulty finding a suitable location.

“We’re not blaming cats for what they do, but we have to recognize the harms that they cause in the environment and that they’ve been introduced by people,” said Grant Sizemore, director of invasive species programs at the American Bird Conservancy.

“We’re not talking about the extinction of cats, we’re talking about protecting life found nowhere else in the world. And once they’re gone, they’re gone forever,” he said. “You can either have cats roaming the Hawaiian landscape or we can have native birds, but unfortunately we can’t have both.”

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