Saturday, September 8, 2012

Stories of a wannabe frog biologist



Recently I spent an evening looking for leopard frogs in a lake located very near the Arizona-Mexico border.  It's called Peña Blanca Lake.  It's not a naturally-occurring lake; it's impounded, it has lots of non-native crayfish and fish, but it's still a beautiful place with enough water to float a boat.

Ready to launch.
Peña Blanca Lake was drained in 2008 to remove sediment contaminated by mercury from gold and silver mining operations in the hills around the lake, then it was allowed to refill through natural rain events.  It reopened again in 2009.

At the time it was drained, a lot of effort was made to eliminate bullfrogs in the lake and surrounding area.  You see, bullfrogs are native to the eastern part of the U.S., but not the Southwest.  And as cute and cuddly as they may be, they're actually one of the most voracious predators out there and have really taken a toll on the native frogs, fish, and snakes in this area.  I have no doubt that if they had the ability to wrap their mouths around your average-sized human being, we'd no longer be at the top of the food chain.



Even though bullfrogs were cleared out of the lake a few years ago, they're actually evil tenacious bastards bent on world domination, which means (in the words of Mad-Eye Moody) it takes Constant Vigilance to make sure they don't move in again and eat the crap out of the native frogs that found their way back to the lake when they figured out it was no longer a death trap.

So every few months a team of biologists makes its way to the lake, headlamps and frog calls in hand, to figure out what's going on.  Or at least to try to.

Floating frog biologists.
The process involves floating around the perimeter of the lake alternately playing the calls of the two native frogs, the Chiricahua leopard frog and the lowland leopard frog, as well as the bullfrog, and shining your headlamp along the shore to see if you can glimpse the shine of their eyes.

Frog biologists in their natural habitat.
One thing you don't fully realize until you start shining a headlamp into the undergrowth is exactly how many other creatures are out there (no doubt also bent on world domination), and exactly how many of their eyes shine back at you.  Like spiders.  And moths.  And deer.  And leopards.  No, not really, there aren't any leopards in these parts.  (Except in frog form, of course.)

Rare sighting of a frog biologist at night.
There are, however, jaguars.  Which are pretty cool.  I'm guessing their eyes shine at night, too.

So anyway, all of these thousands of shining eyes glittering back at you are pretty and yet creepy at the same time.  Rather, they're pretty creepy.

We didn't detect an over-abundance of leopard frogs in the lake that night (unless two is too many), but we also didn't detect any bullfrogs, which is always good news.  The quest against those wily bastards continues, so hopefully at least a small part of Arizona will remain available for our native fauna to inhabit.  Constant Vigilance!

Of course, for me it's mostly an opportunity to wash the dust off my boat and float around a beautiful desert lake.  I'm not sure how much I actually contribute to the cause, except maybe to get in the way.  But hey, if that's enough, I'll try to do my part.

My happy place.  Wait, you want me to do something?

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