Several invasive pests, including red swamp crayfish, American bullfrogs and nutria rodents, can now be found in the Sacramento-San Joaquin River Delta. At the same time, native snakes that feed on these species are struggling. Some are classified as threatened and their populations are continuing to decline.
This study will investigate the relative abundance, habitat use and diet of snakes at four sites in the Delta. The GPS location and type of habitat being used by snakes will be recorded, and the thermal profile of the microhabitat will be analyzed with infrared cameras. Captured snakes will also be stimulated so they regurgitate their gut contents, revealing what species they’ve consumed. (No single snake will be stimulated more than twice in a season.)
The results will help illuminate the role native snake species — highly impactful but understudied vertebrates — can play in controlling invasive pests, which can in turn inform management plans. Because snakes will be tracked in a diversity of sites, some of which are protected and others that are unprotected, the study may also help illuminate priority areas within the Delta that merit future protection.