Every morning, Peter Bradley and his wife, Vicki, walk around their house to assess the latest damage from rabbits trying to burrow underneath the foundations.
“Everyone’s on edge about it,” the Bass Coast resident says.
“Every time I fix the damage, they try to get under the house again. If you leave it undone, the rabbits get worse and worse.”
Bradley’s daily routine of sweeping up displaced mulch and wire and filling holes has become a grim ritual shared across the picturesque coastal region south-east of Melbourne, where rabbit numbers have exploded to what locals describe as plague proportions.
Harold Jackson has lived on Phillip Island for 27 years, but says this is the worst he’s ever seen the rabbit problem. The damage to his garden in Cowes, the island’s main township, has cost close to $20,000.
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“It’s just ongoing,” Jackson says. “They dig holes … they constantly dig my roses and get to the roots.”
Last month, the Bass Coast shire council voted unanimously to develop a new eradication plan, admitting that 15 years and $180,000 in professional rabbit control has failed.
The surge in coastal rabbit populations may be explained by environmental conditions which undermine Australia’s biological control program, says rabbit expert Dr Brian Cooke. Cooke has studied the animals for nearly 60 years and worked on successful eradication programs including on Macquarie Island. He believes a benign virus called RCV-A1 may be protecting rabbits from Australia’s main biological weapon – calicivirus.
“The distribution of these non-pathogenic viruses is largely coastal. It’s in the high-rainfall areas and it doesn’t go into the drier parts of inland Australia,” says Cooke, who is patron of Rabbit Free Australia.
Cooke says RCV-A1 provides cross-immunity. Rabbits infected with the harmless virus become immune to the deadly rabbit haemorrhagic disease virus (RHDV), also known as calicivirus, that Australia has relied on since 1995. In coastal environments, with year-round green grass supporting year-round breeding, exposure to RCV-A1 is greater.
Dr Tanja Strive, a CSIRO senior principal research scientist who has worked extensively on RCV-A1, says lab testing has shown “some cross protection” from calicivirus in rabbits previously infected with the benign virus, and it’s long been observed that the control was less effective in coastal areas.
“When the first calicivirus got off Wardang Island and spread, it wiped out over 90% of rabbit populations Australia-wide, except in some of these more temperate areas, including coastal areas,” she says.
The Bass Coast’s combination of natural coastal conditions and suburban development can create what Strive calls an “upward spiral” for rabbit immunity. “In coastal areas there’s higher rainfall, and in peri-urban areas, we create this feed without the rainfall by irrigation,” she says. “Once the population is dense, then that again fosters the transmission and spread of this benign virus, which then will make them even more immune.”
‘They undermine everything’
For resident Carola Adolf, who has lived on her Bass property for 35 years, the rabbit explosion has made daily life dangerous. While mowing her property, her ride-on mower unexpectedly fell into a hidden rabbit hole, causing her to bite her tongue and bleed heavily.
Her property, once used for horse riding instruction, can no longer be safely maintained. Her horses are at constant risk of broken legs from stepping in holes. “They are 500kg and if they step on this, they would break their leg,” she says, pointing to burrows around the horse shed.
Rabbits cross the road in their hundreds at night.
“When I come home at night, the whole road is just moving. It is scary,” she says. “They undermine everything including fences. They undermine the root system of trees.”
Tackling the problem requires cross-government coordination that, so far, hasn’t happened.
“We’re very much looking for new ideas because what we’ve seen in the past just hasn’t worked,” says councillor Mat Morgan, who seconded the motion to develop a new eradication plan for the Bass Coast shire. “And it’s not something we can do entirely from local government alone. We’ve got Deeca [the Victorian Department of Energy, Environment and Climate Action] controlling a lot of the beaches, Phillip Island Nature Parks operating the penguin parade and a bunch of our environmental assets, and council managing other parts. We’re working with four or even five different land managers.”
The 27-year-old says he’s spent 12 months “watching bureaucrats working in silos … every level of government in every department … reinventing the wheel” rather than coordinating solutions.
Jack Harris, the coordinator of the Bass Coast Landcare Network’s rabbit project, says rabbit management varies wildly between landholders.
“You could probably get one landholder who did a very good job on rabbit control and someone else who wasn’t interested,” he says. “And as a result, you’d always have this mosaic of properties, some where no rabbits and some where they are, and you’d never really get on top of that program.”
Community resistance to common and effective anti-rabbit strategies, such as baiting, adds another layer, Cooke says. “Some people are going to worry that their dog might get poisoned.”
The need to protect endangered eastern barred bandicoots, reintroduced to Phillip Island after being declared extinct on mainland Australia, further complicates control efforts. Baiting can’t be used in areas with a known bandicoot presence.
But Cooke says a large rabbit population has ecological implications: it supports a high volume of feral predators, such as foxes and cats, which also hunt native fauna; and it does significant damage to native plants.
Morgan says the invasive pests are undermining the region’s green credentials. “I think Bass Coast and Phillip Island specifically, you have a real opportunity to become a haven for endangered wildlife,” he says.
“We’ve seen all sorts of endangered wildlife that have been brought to Phillip Island for a place of refuge. And if we can further enhance that biodiversity by controlling the rabbit populations, it does provide us with an extraordinary opportunity.”
For now, he says, the council has been tasked with producing a report on eradication options.
Cooke says that Australia has also lost institutional knowledge about rabbit control because biological control worked so well for decades that “very few people under the age of 50 have ever really experienced high rabbit numbers”.
“Most of the population has very little understanding of what rabbits can do in large numbers,” says Cooke. “People are sort of getting back to the realisation that rabbits aren’t this cute little Beatrix Potter thing, they’re actually a major problem.”
Eradication efforts should start as soon as possible, he warns. “It’s better to do something now than in another five years’ time when you’ve got twice the problem and twice the cost.”
