Abstract 166 – Fine-Scale Behavioral Patterns of Newly Recolonizing American Black Bears in Texas

Nicole Dickan, Justin T. French, Dana L.Karelus, Matthew O. Hewitt, Amanda M.
Veals Dutt, Louis A.Harveson

American black bears (Ursus americanus) began recolonizing western Texas, U.S.A. in the 1980s
after being extirpated from the state. However, recolonization has been slow in this sky island-
desert ecosystem and black bears remain a threatened species in Texas today. Despite their
protected status, little is known about this population and information on their behavioral
patterns is severely lacking. Therefore, we collared 22 bears with GPS collars programmed with
2-hour fix rates. Using hidden Markov models, we segmented the movement paths of 17 bears
(11 M, 6 F) into 4 behavioral states based on probability distributions of step lengths (SL),
turning angles, residence times (RS), and revisitation rates (RV). We found evidence of four
states, consistent with resting, foraging, and dispersive movements, as well as a distinctive
behavior when using point attractants (e.g. deer feeders). The resting and attractant states
both represented localized movement behaviors (x̄SL = 8.2 ± 0.1(SE), 151.4 ± 5.0) but the
attractant state was distinguishable by disproportionally high revisitation rates and residence
times (x̄RT = 41.1 ± 0.6, x̄RV = 6.6 ± 0.1). There were daily and seasonal patterns in the
proportions of fixes in each state. Traveling was most prevalent during early morning, evening,
and in summer. The attractant state was most prevalent in fall during hyperphagia. We then
examined the influence of environmental covariates on the transition probabilities between
states to investigate which abiotic and biotic factors influenced where bears made specific
behavioral decisions. Understanding drivers of bear behaviors can improve our ability to predict
future behaviors in novel environments as they continue recolonization and allow us to predict
future conflict areas. Additionally, understanding habitat characteristics associated with these
behavioral processes will be crucial for identifying key areas in need of protection for long-term
population viability.