Richard M. Engeman

Monitoring coyote population changes with a passive activity index

A passive tracking index method that has been successfully applied to dingoes (Canis lupus dingo) in Australia was shown to have more general applicability to wild canids by monitoring coyote (Canis latrans) populations in southern Texas. The index was calculated simultaneously for multiple species of animals from observations on the number of intrusions onto a series of tracking plots over several days. We found that the index reflected changes in coyote activity before and after a trapping program on each of 2 ranches. We also were able to simultaneously monitor bobcat (Felis rufus) and white-tailed deer (Odocoileus virginianus) populations, producing some interesting (and unexpected) insights. In our study area, we found it difficult to distinguish the number of rabbit and rodent intrusions into the plots, but these animals might be indexed in other habitats. Analyses of the data as binary responses (presence or absence of spoor on each tracking plot), as has been done in scent-post surveys, reduced the sensitivity and accuracy of inferences.