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.

Hematologic, biochemical, and endocrine characteristics of bobcats during a prey decline in southeastern Idaho

We studied the hematology and blood chemistry of 33 adult bobcats (Felis rufus) captured from 1982 through 1985 in southeastern Idaho during a decline in lagomorphs, their major prey. Our objectives were to relate blood physiology of bobcats to sex, season, and a decline in abundance of black-tailed jackrabbits (Lepus californicus) and Nuttall's cottontail rabbits (Sylvilagus nuttallii). Males had higher (P < 0.10) erythrocyte counts (RBC) and hemoglobin levels (Hb) and lower (P < 0.10) insulin concentrations than females. Bobcats sampled during spring had higher (P < 0.10) mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and'insulin levels, and lower (P < 0.10) Hb, packed cell volume (PCV), RBC, and cholesterol levels than bobcats captured in autumn. The decline in lagomorph prey abundance from 1982 to 1983 was reflected in bobcat blood by lower (P < 0.10) phosphorus and insulin levels and higher (P < 0.10) Hb, RBC, and PCV. Progesterone levels in females reflected field results indicating that reproduction was curtailed when prey was scarce.