CORTEZ JOURNAL (Colorado) 28 June 08 Leaping lizards - Zoologists lasso desert reptiles to study habitat (Stephanie Paige Ogburn)
On a hot, buggy morning out in the southwest desert near Cannonball Mesa, Rob Schorr and Brad Lambert leaned in close and delicately tied a radio transmitter around the body of a medium-sized lizard.
The two zoologists, who work with the Colorado Natural Heritage Program at Colorado State University, were helping Dolores Public Lands employees kick off a three- to four-week lizard survey. This week, the team of scientists will catch up to 13 lizards and outfit them with small radio transmitters.
After that, public lands employees will use the radio signals to track lizards within their territory, spending the next few weeks figuring out where they roam and the type of habitat they prefer. The survey targets two specific kinds of lizards, the long-nosed leopard lizard and the collared lizard, which both live in a mixed desert scrub and pinyon pine and juniper desert environment out in Canyons of the Ancients National Monument.
On this survey, the team was catching lizards out on Risley Mesa, just north of Cannonball Mesa, down McElmo Canyon.
“They’re definitely out here, so we’re just trying to figure out the habitat they’re keying in on,” said Eric Freels, wildlife technician with Dolores Public Lands.
But first the team has to catch each lizard and tie the small transmitter to its back.
There’s no expert technique to lizard-catching. Teams of technicians spread out in a rough line and walk in one direction through the desert environment, keeping a sharp eye out for lizards sitting atop rocks or hiding in the underbrush.
“Look out on the rocks; see if there are any,” said zoologist Lambert. “Then you can noose ’em before they run off.”
When a technician spots a lizard, he sneaks up close to it, carrying a “lizard lasso.” The lasso consists of a pole about 4 feet long, with a noose, or lasso made of a fine filament, like fishing line, hanging from the pole.
The would-be lizard catcher slowly loops the lasso over the lizard, and when the lizard runs forward to escape, the noose tightens like a lasso, trapping the small reptile.
“(It’s) the real high-tech technique — fish on a line,” Lambert said facetiously.
On Tuesday morning, the team’s first catch of the day was a long-nosed leopard lizard. The spotted reptile lay still in a mesh net while zoologist Schorr measured its length and weight. Then Schorr and Lambert teamed up to hold the lizard and tie on the transmitter.
The process took just over six minutes. Then they let the lizard go, and it scurried off under a juniper tree.
Later on, wildlife technicians will return and locate the lizard using its radio signal. When they find it, they’ll record data about its location and the microhabitat where they found the animal, from vegetation cover to the amount and types of rocks in the area.
The public lands office wants to know about the habits and preferred habitat of the leopard lizard because it is a sensitive species in this part of the country, said technician Freels. This area of Colorado is the easternmost part of the lizard’s range, so they aren’t as prolific as they are in more Western states, like Nevada.
The long-nosed leopard lizard is hard to find, since its spots camouflage it into the speckled shade underneath bushes, where it can hide.
“They’ll just sit there, usually, and it’s impossible to see ’em,” Freels said.
The collared lizard, in contrast, is easy to see, but when technician Mike Schmidt tried to catch one Tuesday morning, it quickly ran away.
The team has had good success catching lizards. They had caught four long-nosed leopard lizards and one collared lizard by Tuesday morning. The species, although not sensitive, seemed more elusive.
Later in the morning, Freels and two seasonal technicians went out to track a collared lizard they caught on Monday. Technician Serena Rocksund handled the receiver, which beeped more loudly as she neared the lizard’s location.
Rocksund located the lizard, which was not visible, since it was hidden in a burrow or under a rock, by honing in on the spot where the beeps were the loudest. The team then got a GPS location on the lizard, which had only ranged a few dozen feet from where they had caught it on Monday.
The public lands researchers hope that this data, coupled with data they collected from a lizard survey two years ago, will help them understand what specific sorts of habitat long-nosed leopard lizards prefer, and how they compete with collared lizards. If they can learn this, then the public lands managers can make management decisions with an eye to keeping the sensitive species’ habitat intact, Freels said.
Zoologists lasso desert reptiles to study habitat