OUTDOOR BRIEF

REPTILE SEASON

Rocks and sticks on the road may be lizards, snakes

Have you ever driven along an empty road on a warm spring night and seen what appears to be rocks and sticks on the roadway? If so, pay attention to your driving because it's reptile season, and there is a good chance those rocks and sticks might actually be lizards and snakes, said Polly Conrad, reptile biologist for the Nevada Department of Wildlife.

Conrad has just wrapped up her nighttime road surveys, an annual opportunity for Conrad and other biologists to look for a group of animals called herpetofauna, or herps, for short. The herp group includes both reptiles and amphibians -- snakes, lizards, turtles/tortoises, frogs/toads and salamanders.

In Southern Nevada, biologists generally complete their herp road surveys at night and during the months of April through June, because that's when most of the animals "hit the road" in search of the warmth the asphalt provides. Early spring is the time of year that snakes and lizards leave their burrows, rock crevices or other refuge sites where they lived through the winter. Generally, large numbers of nocturnal herps will not be seen until the nighttime temperatures are consistently more than 60 degrees Fahrenheit.

On the other hand, by the time July arrives with nighttime temperatures that hover near 85 to 90 degrees, you won't see as many herps on the roads in Southern Nevada because air temperatures are warm enough that herps do not necessarily need to seek the warmth stored in the asphalt. One of the exceptions to this rule of thumb is the heat-tolerant western banded gecko, which will still be out during the hottest nights in the Mojave Desert.

As a rule, Conrad begins her nocturnal road surveys in late April, but with the unusually cool nighttime temperatures Southern Nevada experienced this spring, she was delayed until June. Herp road cruising surveys are usually conducted on paved roads in remote areas of Southern Nevada, roads that experience light nighttime traffic and pass through good herp habitats. Depending on the species, good habitat can be open desert scrub or mid-elevation Joshua tree forest.

Conrad starts her nightly survey regimen at about 9 p.m. and works until anytime from 11 p.m. to 1 a.m., depending on the length of the road and the number of herps observed. She conducts surveys by driving slowly with either the headlights, a flashlight or a spotlight aimed at the road directly in front of her vehicle so she can clearly see the road. It takes a certain focus to spot these animals on the roads; an inexperienced surveyor can start by looking for things like rocks and sticks, or other odd shapes on the road.

Once something is sighted, Conrad pulls her vehicle off to the side of the road so she can take a closer look at the find. Sometimes it is merely debris on the road, and sometimes it is a specimen, either AOR (alive on road) or DOR (dead on road). And although you would expect a live animal to flee when approached, they often sit still, likely still soaking up the warmth or thinking they are camouflaged.

However, snakes will let you know your presence bothers them by coiling up, hissing or striking. Rattlesnakes will usually shake the rattle on the end of their tail as an unmistakable warning that you are getting too close and need to back off. When encountered during a herp survey, rattlesnakes are measured only if two herpetologists trained to handle venomous reptiles are available to appropriately restrain it. A biologist uses a snake hook and net to capture the snake and then puts its head in a tube so it can't bite anyone. At this point, the rattlesnake can be measured, sexed and marked without harm to the biologist.

During the herp surveys, all located specimens are identified by species, measured, aged, sexed, and their location noted. Because the sightings are weather-related, biologists also record the ground temperature, the ambient (air) temperature, the wind and the preponderance of precipitation.

On a windy night, there will likely be less of these animals to see because most will be taking cover.

To the layman, a full moon might seem the perfect aid to assist in spotting animals on the roads. However, "Some research shows that the animals are hindered by the light of the full moon, as they may be more easily seen by predators," said Conrad. That said, Conrad has observed herps on both new and full moon nights. "Temperature and rain appear to be more important in the sightings," she said.

While surveying for herps, biologists also take note of other wildlife species as they see them. Seeing rodents and rabbits during the survey is a good indicator there is an abundance of food available for snakes. Likewise, seeing a lot of insects means there is a good food source for lizards and amphibians. Other night-hunters are also likely to be seen on the surveys.

The data gathered through nighttime surveys is compiled with data from pitfall trap and other surveys.

Biologists then look for trends with regards to numbers of different species and how they are related to climate factors over time.