Common wall lizard in Victoria - 700,000 of them?

Two common wall lizards sunning themselves at my friend's place near Esquimalt, BC.

Canada and lizards.  Not something normally associated with each other.  Sure, we have our Northern Alligator lizards and even the odd blue-tailed skink, but something as odd as a Mediterranean reptile running loose in the retirement capital of The Great White North, never.  Right?

Well, it's true.  Many years ago, a few of the creatures were released or escaped from Saanich, BC, which is several kilometers away from central Victoria.  A female will lay a clutch of 3 to 11 eggs once or twice a year, weather depending.  There are few natural predators for these wry, fast lizards and the conditions on the southern tip of Vancouver Island are well within their range of tolerance.  This has resulted in a population explosion, resulting in an estimated three-quarters of a million of them.  And it is not stopping there.

They have been found on the Gulf Islands.  The little stow-aways can easily hide in cars or transported materials and are spreading through various means.  It has been estimated that the radius of increase is about one kilometer every ten years.  After 50 years, that represents almost 20,000 acres.  You can imagine the opportunities within that area over that time to spread by other than natural means.

Are they invasive?  While they are harmless to humans and may even be helpful regarding insect control, they are also in competition with native alligator lizards and may consume beneficial insects such as lady beetles, ground beetles, and pollinators.  They consume invertebrates but also take berries and small fruits.  Even the young of some vertebrates such as alligator lizards are not immune from predation.  

With their rapid rate of increase, low mortality from predators, competition with native species, and the consumption of beneficial organisms, the common wall lizard represents an invasive threat.  Much of Canada is uninhabitable for them with our cold winters, but I have to believe they could exist wherever the northern alligator lizard does.  What populations will look like in a hundred years is uncertain, but you can bet they are not done expanding their range.  Not by a long shot.

Close-up of a common wall lizard photographed in Esquimalt, BC.

Thanks for reading.

Eric Svendsen     www.ericspix.com



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