Plot placement when using a passive tracking index to simultaneously monitor multiple species of animals

We evaluated a passive tracking index (PTI) when plots were placed on lightly used dirt roads versus placement on naturally occurring bare ground in natural habitat. PTIs were calculated before and after removal of coyotes and some non-target species during another study that evaluated capture devices. Six mammals were simultaneously monitored with the PTI: coyotes, raccoons, white-tailed deer, feral swine, javelina, and rabbits. PTIs from road plots were significantly higher than from off-road plots, except for deer and javelina, for which no differences were detected. After removal of coyotes, PTIs were significantly lower, both from on-and off-road plots. For coyotes and raccoons, the decline in index values primarily reflected population reductions. For animals hunted for sport (deer, swine, javelina), population reductions were minor compared with coyotes, and their declines in index values likely reflected conditioned responses to the activity and shooting that accompanied evaluations of the capture devices. We conclude that the PTI is sensitive to changes in population or changes in activity in response to an event for a variety of species, and it is most useful when placed on lightly used dirt roads.