SOUTHEASTERN NATURALIST 2009 8(3):437–444 Mud Track Plots: An Economical, Noninvasive Mammal Survey Technique Ross R. Conover 1,* and Eric T. Linder 2 Abstract - The active component (e.g., bait or scent lures) common to mammal survey techniques can bias detectability (e.g., aversion or attraction) and reduce their efcacy for spatially explicit, habitat-use research. We overcame this obstacle with 1-m 2 mud track plots, which use natural ground substrates to sample mammalian species’ occu- pancy with minimal bias of natural movements. Performance of this method was based on criteria that included implementation effort, cost, species detection, proportion of plots to capture tracks, and species identication by track capture. Mud track plots were quickly established, maintained, and monitored with minimal effort and cost. We recorded tracks in 85% of plots over 8 nights, documented all visually conrmed medium and large-sized mammals (>800 g), and captured identiable (>98%) tracks on a row-crop farm in the Mississippi Alluvial Valley. Drawbacks included limited ap- plication for small mammals, potential ambiguity of using track imprints for species identication, and weather-dependent, spatio-temporal restrictions. Mud track plots are an inexpensive, simple approach to noninvasive mammal detection. Introduction Occupancy information provides insight on a variety of spatio-temporal habitat-use patterns and ecological effects (Vojta 2005). Several noninvasive (i.e., does not require capture or handling) survey techniques have been successfully implemented to obtain occupancy data for varied taxa and re- search objectives (Connors et al. 2005, Mooney 2002, Savidge and Seibert 1988), with some common methods including camera traps, track plates, snowtracking, scent stations, and scat surveys (Gompper et al. 2006). The versatility and low-cost of track-plate methods has resulted in their use to evaluate area species-richness (Silveira et al. 2003), predator activity (Con- nors et al. 2005, Kuehl and Clark 2002), general habitat-use (Fecske et al. 2002), relative abundance (Mooney 2002), and species occupancy (Mowat et al. 2000, Smith et al. 2007). The efcacy of track plates depends on ar- ticial components (e.g., bait, scent, boxed enclosures, or media-tracking platforms) to enhance mammal attraction and track identication (Foresman and Pearson 1998). However, the potential of these components to invoke attraction or aversion responses may also limit track-plate applicability for research that requires information on natural mammal movements. Track-capture methods that detect mammals without inuencing their natural movements can elucidate habitat-use patterns at smaller spatial scales 1 Department of Natural Resource Ecology and Management, Iowa State University, 339 Science II, Ames, IA 50011. 2 Department of Biological Sciences, University of Texas – Brownsville, 80 Fort Brown, Brownsville, TX 78520. * Corresponding author - melospiza77@yahoo.com.