Young female black bears in Asheville, North Carolina, are big, have
cubs early

Date:
September 9, 2021
Source:
North Carolina State University
Summary:
Black bears (Ursus americanus) reproduced at a younger age in
urban areas and were nearly twice the size of bears in national
forests shortly after their first birthdays.



FULL STORY ========================================================================== Black bears (Ursus americanus) reproduced at a younger age in urban areas
and were nearly twice the size of bears in national forests shortly after
their first birthday, researchers from North Carolina State University
and the N.C.

Wildlife Resources Commission found in a new study.


========================================================================== Published in the Journal of Mammalogy, the study of the reproduction and
size of wild black bears living in and around the city of Asheville,
North Carolina, has important implications for managing urban bear
populations. Also, the results raise questions about the foraging
activities and diet of urban bears, and whether food from people or an abundance of natural food could be providing the bears with a reproductive advantage.

"Some of the bears in Asheville are reproducing at a young age, and they
are big," said the study's lead author Nick Gould, postdoctoral research scholar at NC State. "It definitely leads us, as researchers, to ask
additional questions: What's driving this kind of weight gain in young
bears this early in life? Are they eating natural foods, bird seed and ornamental fruit, or feeding on residential garbage?" For this study, researchers collaborated with the residents of Asheville to capture
black bears on private property between April 2014 and September 2018.

The bears were temporarily sedated and then released on-site where they
were captured. Researchers collected data on the bears' weight, age,
general condition, sex, and other information. The research team used GPS-equipped radio collars, which were designed to fall off naturally
or to be released remotely, to track the female bears to their den sites
to monitor reproductive activity.

They collected data on a total of 36 female bears around 1 year of age
in Asheville. As a point of comparison, the researchers used data from
three previous studies of bears living in rural areas in national forests
in North Carolina and Virginia. They compared the data for urban female yearling bears to data for 95 female yearlings in rural forested areas.

Researchers determined that the 36 female bears in Asheville weighed
an average of nearly 100 pounds at 1 to 1 and a half years of age. In
contrast, the sample of 95 female bears living in the three national
forests weighed an average of 50 pounds at a similar age.



==========================================================================
Of the 12 female bears they were able to track back to their dens by their second birthdays in Asheville, seven produced a total of 11 cubs. In comparison, none of the three studies of bears in rural forested areas
found that bears produced cubs by their second birthday.

"We didn't expect 2-year-old females to be giving birth," Gould
said. "Based on what we know about black bears, we thought we'd see
litters from bears 3 years of age and older. These results open up new
areas of research to learn more about wildlife living among people in
developed areas." The researchers analyzed and compared the availability
of an important natural food source for bears -- acorns and other nuts --
and didn't find differences that could help explain the larger size of
these young female bears in the city.

However, researchers didn't examine the availability of other important
natural food sources like berries and didn't investigate whether bears
were eating bird seed or food and garbage left out by people. That is
the current focus of ongoing research in the Asheville area led by study co-author Chris DePerno, professor of fisheries, wildlife and conservation biology at NC State, with Gould and graduate student Jennifer Strules.

"Interestingly, natural food production, in the form of nuts and other
'hard mast' food sources, did not influence cub production for urban
bears," Gould said. "We are left to conclude that either natural foods,
in the form of soft mast like berries, or anthropogenic food sources in
the form of garbage, bird seed, ornamental fruit trees or intentional
feeding by people, is influencing the weight gain and early reproduction." Reproduction is one piece of the equation needed to better understand
black bears inhabiting urban areas. Researchers said that while they
appear to be reproducing earlier in some cities, urban bears' mortality
may also be high, as they are more likely to be involved in collisions
with vehicles.



==========================================================================
"If mortality is high enough to exceed reproduction, then that population
is likely going to be a sink," Gould said. "If bears are attracted to Asheville, and they establish residency because of the supplemental
food sources it offers, they're also going to be exposed to collisions
with vehicles, legal harvest, and other anthropogenic threats, and
therefore mortality may outpace reproduction, suggesting the population
might be functioning as a sink." This study is part the North Carolina Urban/Suburban Bear Study, initiated by NC State and the N.C. Wildlife Resources Commission to understand urban black bears' survival and causes
of mortality, movements, reproduction and other factors when they live
around cities. The goal is to help wildlife managers develop better
policies for bears and other wildlife near cities.

"The entire objective is to help the Wildlife Commission better
manage bears," DePerno said. "The urban-rural interface is larger with population growth and development, and that puts greater pressure on
wildlife populations.

"We have a situation in western North Carolina where we have people in
a wonderful area with a lot of bears," he added. "We want to understand:
Is this a source or sink population? Are the bears moving into huntable
areas? Are they considered more as residential or transitory? We are
trying to understand what these bears are doing and their entire life
history, including what is killing them, and what are they eating."
Researchers also want to help educate the public.

"We want to provide good information about black bears based on the
science, so we can help guide people in urban areas with bears, in
Asheville or otherwise, to live responsibly with them," Gould said.

The study, "Growth and reproduction by young urban and black rural bears,"
was published online July 10, 2021, in the Journal of Mammalogy. In
addition to Gould and DePerno, the other co-authors were Roger Powell
and Colleen Olfenbuttel. The project was funded by the Pittman-Robertson Federal Aid to Wildlife Restoration Grant and is a joint research project between the N.C.

Wildlife Resources Commission and the Fisheries, Wildlife, and
Conservation Biology Program at North Carolina State University ========================================================================== Story Source: Materials provided
by North_Carolina_State_University. Original written by Laura
Oleniacz. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Nicholas P Gould, Roger Powell, Colleen Olfenbuttel, Christopher S
DePerno. Growth and reproduction by young urban and rural black
bears.

Journal of Mammalogy, 2021; 102 (4): 1165 DOI:
10.1093/jmammal/gyab066 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/09/210909162234.htm

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