As the funding for our trapping project finally came through, we spent the first two weeks of the month building our trap sites up in the Ferris Mountain region of our field office. It was physically demanding work but essential for our project and rewarding in its own way. Each trap site consists of three cover boards and a Y-shaped drift fence with a pit-fall trap in the middle of each arm and a funnel trap at each end. The fence is designed to encourage animals to either enter the funnel trap or fall into the pit fall traps. We have twelve trapping sites; six within exclosures and six outside of them. This is in an effort to compare the type of species that occur in grazed versus ungrazed areas.
The purpose of the trapping project is to inventory the herptile species that occur in the area, assessing both the diversity and the abundance of species. We will also be comparing species occurrences between grazed and ungrazed sites. We trap for ten consecutive days, checking each trap daily. We will do three sets of trapping total, one set per month. As herptiles go this month, we caught many Wandering Garter Snakes (Thamnophis elegans vagrans), two Bullsnakes (Pituophis catenifer sayi), a Northern Leopard Frog (Lithobates pipiens), and a Prairie Rattlesnake (Crotalus viridis). When we catch a snake we will insert a pit-tag just under its skin to track if a snake is a recapture or not. We will also cauterize a small part of the snakes scales in a systematic numbering system as another way to identify different recaptured individuals. For frogs, we mark them by preforming toe-clippings and again use a specific numbering system to tell between different individuals. Since our traps don’t discriminate we also catch plenty of mammals. Most of what was caught were Deer Mice (Peromyscus maniculatus) and voles. However we also caught Masked Shrews (Sorex cinereus) and Northern Pocket Gophers (Thomomys talpoides).
I hope to catch more rattlesnakes as the season goes on, they are a fascinating species to work with. Before handling a rattlesnake we will use a tongs to guide the posterior of the snakes body into a tube so there is little risk of the snake being able to bite you. Once tubed the snake can be handled safely and is processed the same as any other snake that we catch.
Before trapping we spent a day doing surveys for the Greater Short-horned Lizard (Phrynosoma hernandesi). Surveys for horned lizards consists of walking transects and scanning the ground for the well camouflaged animals. Once one is spotted they are pretty easy to capture by hand as they are relatively slow. Horned lizards main defense against predators is their camouflage. Their flat-bodies cast very little shadow and they will often stay completely still when you pass by making them even more difficult to notice. When one is captured, if it was not a recapture, we will pit-tag it.