Check out this very helpful paper on how detector dogs were trained to conduct surveys to find the threatened Eastern Indigo Snake. This paper is a great look into training and survey methods for detector dogs aimed at identifying specific species.

Read the paper here:

https://www.academia.edu/29512518/Herpetological_Review_Using_a_Wildlife_Detector_Dog_for_Locating_Eastern_Indigo_Snakes_Drymarchon_couperi_