OSU graduate students conduct black bear population studies
STILLWATER – As the weather warms and vegetation begins to grow, the black bears living in southeastern Oklahoma will begin to come out of their dens.
Before they do, however, graduate students in Oklahoma State University’s Department of Natural Resource Ecology and Management, went to the known locations of several bears to gather some information. Morgan Pfander, doing her graduate research on the bear population in and around the Ouachita Mountains, recently led a crew of nearly 20 to check on a momma bear and her cub.
“We record weight, chest girth, sex and distinguishing marks for the cubs,” Pfander said. “We also give it a PIT tag, a passive integrated transponder, which we can scan for identification purposes if we ever catch the cub again.”
To date, the researchers have 66 bears marked with the central objective of determining the current population status of American black bear in southeast Oklahoma.
“I am in the field throughout the year, running trap lines in the summer to capture bears for the mark/recapture portion of my study, tracking collared bears to their dens in late winter, and visiting dens in late spring to collect reproduction data and vegetation measurements at the den sites,” Pfander said.
Oklahoma black bears were all but eliminated by the early 1900s, but recent decades have seen bears recolonize in portions of their old stomping grounds. After initial studies on the species’ demographics and range, the Oklahoma Department of Wildlife Conservation opened a hunting season on the bears in 2009. Questions soon arose regarding the effects of the hunting season on the population, leading to the funding of several graduate projects, including Pfander’s.
“Although we only have preliminary data, we are finding a female-biased sex ratio,” she said. “Ten years ago they didn’t find that the sex ratio was statistically different from 1-to-1.”
Female-biased sex ratios have been noted in other core habitat areas of well-established black bear populations, so the thought is the population has “settled in” a bit more since the early studies, when the bears were just beginning to reestablish themselves in the state.
“There are not many places where a large carnivore species has been able to naturally recolonize part of its former range, but it has here in Oklahoma,” Pfander said. “The timeline of this recolonization and the implementation of a hunting season presents us with a unique combination of demographic influences, as well.”
It will not be long before the bears come out of hibernation and start their cycle all over again. Females will breed in the summer, but delay the implantation of the blastocyst until the fall, allowing them to give birth in late winter during hibernation.
“Beyond my interest in the research question, I also just love bears,” Pfander said. “They are a very interesting and complicated species. They eat everything (mostly vegetation/fruits/hard mast in Oklahoma) and can adapt to a lot of different habitats.”