To satisfy his Fitbit, Gavin Hanke frequently takes long walks from his home in Victoria that double as reconnaissance missions. Observing rock walls, stucco, piles of wood and gardens, which sometimes evoke strange looks from residents, Hanke searches for an invader of the Vancouver Island ecosystem: Podarcis muralis, or the common wall lizard.
When he sees one while “lizard” – easy to do in British Columbia’s capital – Hanke snaps photos with his iPhone, geotags and uploads the images to his growing collection on the iNaturalist app.
Hanke, the Curator of Vertebrate Zoology at the Royal BC Museum, has been sounding the alarm about wall lizards since 2006. Until recently, few communities took notice.
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Native to the Mediterranean, the reptiles seem perfectly happy basking in the sun in the southern half of Vancouver Island. Hanke estimates its current population in British Columbia to be between 500,000 and 700,000. They grow up to 23 cm, but are generally smaller. And with climate change, they seem to be spreading: last year, some were even spotted on the Lower Continent, near Chilliwack.
The lizard’s provenance in BC dates back to Rudy’s Pet Park, a roadside zoo that opened in Saanich in 1957 with monkeys, lions, and among other creatures, a dozen imported lizards from Italy. When the now-late owner Rudy Bauersachs closed it down in 1970, the largest animals went to the Greater Vancouver Zoo. According to academic studies, the lizards he just let go.
The creatures live for up to 10 years, devouring insects, fruits, baby snakes, and local frog species. They even chew on their own young, who, apparently conscious, sneak away shortly after hatching.
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On Vancouver Island, they have established populations in Langford, Ucluelet, Nanaimo and other communities, appearing as far north as Campbell River, 265 km from Victoria. They make sneaky trips hidden in camping gear, and their eggs are transported in plants and potting soil. Children help their distribution by taking them home as pets.
A reptile lover since childhood in Manitoba, Hanke sees dozens daily in his garden. And while tracking and stopping its spread is part of his mandate with the museum, he confesses that, for him, having lizards on his property is “a child’s dream come true.” In the capital region, the species is “so stupidly abundant that we are never going to eradicate it,” he says. “It’s probably wrong to say it, but they’re actually quite charming.”
Still, on a scale of one to 10, Hanke rates the threat to British Columbia’s ecosystems as “an eight, if not a nine.” He is concerned about native species such as the sharp-tailed snake, the Pacific chorus frog, and the northwestern alligator lizard. The lizard on the wall feasts on them all.
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When he discovers new populations, Hanke notifies the municipal or provincial authorities, because wall lizards can be removed from an area if they are detected early. Although British Columbia has a response plan to fend off invasive species, the lizards are so well established that the province is largely dedicated to preventing their spread through awareness programs and encouraging people to report sightings. Some residents are resorting to makeshift measures, such as DIY traps and even BB guns.
Last May, on Salt Spring Island, retired biologist Pat Miller took photos of a lizard lounging on the stone slab steps leading to its back deck, then contacted Hanke. His verdict: wall lizard. Hanke is particularly concerned that the Gulf Islands, with their rich flora and fauna, are a perfect habitat for them. “They are going to love it.”
An alarmed Miller alerted the Salt Spring Island Conservancy, a society dedicated to protecting the island’s native plants and animals, which urged its 270 members to report additional sightings. He initially planned to catch his lizard, but it disappeared for a few weeks after a period of cold weather. He’s seen more since then, and in late July another person had reported a sighting in the same area, near the Vesuvius ferry terminal. “We can still go after them,” says Miller.
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Hanke is in favor of extermination, if done humanely. Some islanders use buckets sunk into the ground with water at the bottom and placed at a 45-degree angle; lizards that glide for a drink can’t get out. Hanke himself employs a technique called “lizard lasso”, using a fishing rod with a small loop at the end: “Just pull up hard,” he says, “and you’ll have it.” To euthanize them, he advises putting the captured lizards in a refrigerator until they fall to a torpid state, then in a freezer. “They have to be frozen,” he warns. “They can survive partial freezing.”
Not everyone sees the creatures as a threat. Last June, the Times Colonist The newspaper was bombarded with heated emails about an article on the best ways to catch and kill them. One reader wrote that his family lives in harmony with the lizards on their farm, adding: “They don’t eat roses like deer, they don’t carry disease like rats, and they don’t buy all of our affordable homes like Toronto residents.”
But Hanke rejects suggestions from some lizard lovers that populations can be left to natural predators. The hundreds of thousands on Vancouver Island, he warns, are agricultural pests that feed on much-needed pollinators. Although Hanke has no direct evidence that lizards eat bees, he believes eyewitness reports that they do. “Them Will They eat mason bees, bumblebees and even wasps, ”he says. “If they take a wasp, they will take anything.”
This article appears in print in the October 2021 issue of Maclean’s magazine with the title “Climbing the walls”. Subscribe to the monthly print magazine here.