Some species even present themselves for counting by sneaking into warm basements, falling into window wells or taking a dip in a backyard pool.
"It's science, but it ain't rocket science," Therres joked.
But it does attract scientists.
Nate Nazdrowicz, a doctoral candidate in entomology and wildlife conservation at the University of Delaware, is a volunteer coordinator and a project folk hero for finding the rare Eastern narrowmouth toad in 11 grid boxes in Dorchester County.
The herp patrol has found at least 48 non-native critters, most likely former pets set free, including a 3-foot black monitor lizard, a Burmese python, an alligator snapping turtle and a boa constrictor.
Bird watchers who worked on a similar project for the Maryland Ornithological Society last decade are finding the same senses being challenged by herping.
"With a project this big, we couldn't do it without the help of volunteer citizen-scientists, from seventh-graders in Calvert County to seniors groups and amateur photographers," said Cunningham.
A nine-member panel reviews all reports for accuracy. That's where the photos or sound recordings come in handy. The error rate on the more than 8,000 entries evaluated so far has been less than 5 percent, Therres said.
Not to say there haven't been reports that have been a few salamanders short of a congress. Toads and frogs can look a lot alike to the uninitiated, and one sighting even tricked biologists, Therres admitted.
It's amazing how much a rotting banana peel in the road can look like a deceased snake.
Maryland Amphibian and Reptile Atlas
Goal: To find as many species as possible in 1,293 grid blocks
Deadline: Dec. 31, 2014
To volunteer: Heather Cunningham, firstname.lastname@example.org