Nature: Tiny lizards blanket Sonoma County

The western fence lizard is best known for its blue belly. (Jocelyn Knight photo)


This time of year, it is nearly impossible to walk on any of our region’s sunny trails without catching a sudden glimpse of a tiny lizard at the edge of the path, squiggling at high speed from one thicket of dry grass to the next like a crazed commuter.

Some August mornings I count more than 50 of them during a 20 minute stroll, each scarcely an inch long. ‘Tis the season that the eggs of the western fence lizard (aka the blue belly or Sceloporus occidentalis) hatch, flooding the ecosystem with a one of the most popular snacks around.

Indeed, so many of our local animals feast on baby blue bellies this time of year, Marin County naturalist David Herlocker has dubbed them “nature’s French fries.”

Like French fries, they are ubiquitous, tasty, and you can never eat just one (at least if you are a bird, or a snake or even another lizard). Even a black widow spider will indulge if a baby lizard stumbles into its web.

The western fence lizard is probably the most commonly seen lizard in California, as the adults like to warm themselves on rocks and are relatively bold around humans. True to their nickname, the adults have characteristic patches of brilliantly blue scales on their bellies, with males sporting even more color on their throats, which comes in handy when trying to attract mates during breeding season (March-June).

About two weeks after mating, females typically lay clutches of 3-17 eggs in a protected patch of damp soil. In fact, if you are a gardener, chances are you’ve encountered at least one clutch of eggs (they look like Tic Tacs on steroids) as you put in your summer garden.

Typically the eggs start hatching en masse from late July until September, which is why we are seeing so many young right now.

But why all at once? Given our relatively mild climate in California, wouldn’t it make more sense for the young to hatch in smaller numbers over a longer period of time?

Not necessarily. Because the parents do not care for the young at all, the small fries are on their own, with nothing but speed and cryptic coloring as a defense. In such situations, many organisms have a breeding strategy called “predator satiation.”

As with human consumers of actual French fries, the idea is even the most avid predator eventually gets full, meaning some baby lizards will be left to carry on the species.

End note: I know it is tempting to try to catch and adopt wild lizards of all types, but please remember that wildlife will only thrive in its native habitat.

I often hear stories from kids about how they “almost caught a lizard but its tail came off.”

Sadly, losing a tail is not as benign as it may seem, as the lizard uses its tail to store nutrients for lean months. A lizard without a tail is like a person with an empty pantry and no ATM card.

If you do choose to catch and hold a baby lizard, the safest way is to cup your hands around it, avoiding the tail, and then gently hold the two legs on either side of its body. The animal will not struggle in this position and can be safely released.

Jeanne Wirka is an interpretive naturalist and resident biologist at the Bouverie Preserve near Glen Ellen.