The riparian brush rabbit was once thought extinct, but a small population still makes its home in California’s Central Valley.
Conservation efforts helped rebuild the species, but when a highly contagious virus deadly to rabbits began sweeping through the region last year, it prompted a frantic effort to once again intervene to protect the species.
The rabbit hemorrhagic disease virus serotype-2 (RHDV-2) has been detected in domestic rabbits with a 90 per cent fatality rate, but this was a first time it has been picked up in the wild — something the U.S. Fish and Wildlife Service called “alarming.”
“Before March , the biggest threat to the rabbits was winter flooding, but the virus poses an unexpected and potentially catastrophic threat,” the USFWS said.
Work began in the San Joaquin River National Wildlife Refuge to trap and vaccinate them against the virus, since the wild animals have no known immunity.
“We needed to capture some of the riparian brush rabbits on the refuge and bring them into captivity temporarily while the safety of a vaccine was determined,” Eric Hopson, assistant refuge manager at the wildlife refuge, explained.
The endangered riparian brush rabbit is found only in CA’s Central Valley. Over 6 months ago, staff & partners at the San Joaquin River National Wildlife Refuge began trapping these rabbits & vaccinating them against the virus that causes a deadly rabbit hemorrhagic disease. pic.twitter.com/u9wsJCZppD— U.S. Fish and Wildlife (@USFWS) April 23, 2021
The small cottontail, which only grows to 12 inches long and perhaps 1-and-a-half pounds, is one of the most endangered species in California.
Experts have been seriously working to protect habitat to rebuilding the population for the past 20 years.
Last August, 20 brush rabbits were caught and moved to a bio-secure area at the Oakland Zoo where they were cared for and assessed for vaccines. Then, trapping and vaccinating of wild rabbits began.
More than 200 were vaccinated in just three months.
Meanwhile, the progression of the virus seemed to slow down giving researchers — and the rabbits a break.
By late last year, the rabbits taken to the zoo were released back at the refuge.
But the work to save the species done yet.
The endangered riparian brush rabbit is found only in California’s Central Valley. We’re working with the California Department of Fish and Wildlife to vaccinate these rabbits against the fatal virus known as RHDV-2.— U.S. Fish and Wildlife (@USFWS) May 10, 2021
Background story: https://t.co/YMcr4nLVhF pic.twitter.com/kXTR3BNweN
This spring, experts set out to find out of antibodies from those vaccines are present.
Rabbits were once again trapped and blood samples taken.
And more rabbits were vaccinated.
Now wildlife biologists/researchers need to know if the antibodies from those vaccinations are still present in the population, so trapping is again underway this week. Blood is being drawn from rabbits vaccinated in the fall, that will be examined for the presence of antibodies. pic.twitter.com/o8OpU6Un2M— U.S. Fish and Wildlife (@USFWS) April 23, 2021
No matter how small, biologist aren’t willing to give up on the riparian brush rabbit.
Efforts of the last two decades is being heralded as a success story and one of the refuge’s “greatest accomplishments.”
“This is truly an endangered species success story; the riparian brush rabbit recovery work has been one of our refuge’s greatest accomplishments.”— US Fish and Wildlife, Pacific Southwest Region (@USFWS_PSW) November 29, 2018
The story: https://t.co/UCxg9BQ65q
Photo: Biologist captures a brush rabbit during a survey of the population by @USFWS #TBT pic.twitter.com/UUBMOhSwv3