Population Dynamics of Mountain Lions 57dispersal, as suggested by some of our first observations. There were cats that we be-
lieved were about to disperse that re entered the region rather than heading east across
this unfamiliar terrain. For example, one of the first subadult males (the age class most
likely to disperse) radio- collared was located during aerial surveillance in a cottonwood
tree (Populus deltoides) along the Cheyenne River, suggesting it was about to move east
out of the Black Hills and into the prairies of western South Dakota. However, later
observations found the lion traversing the southern and western perimeter of the Black
Hills prior to its departure from the region; the male fi nally moved to the Wyoming
portion of the Black Hills and beyond to the west. In fact, these first observations in-
dicated that at least some subadult males were likely leaving the Black Hills immedi-
ately after becoming in de pen dent of their mothers.
We were able to determine dispersal ages for 22 juvenile mountain lions (14 males,
8 females) (Jansen and Jenks 2012). Male mountain lions dispersed at a mean age of
14.7 months, and females dispersed at 15.3 months. Kittens born during spring and in
the early and mid birth pulse (April 1– July 30) dispersed 4 months younger than
kittens born in the last month of the birth pulse and during winter (August 1– January 31).
Kittens that were born in early or mid pulse dispersed during the summer (June–
August) or autumn (September– November) after attaining an age of 1 year; kittens
born late in the birth pulse dispersed during winter (December– February) or spring
(March– May) after becoming 1 year of age. Our findings provided support for the hy-
pothesis that subadult mountain lions move out of the Black Hills at just about any
time of the year; although there were times (September– October) when we expected
that much of the dispersal activity occurred.
One prob lem we had with our attempts to document these dispersals was our use
of traditional VHF radio- collar technology. These collars allowed us to pinpoint
locations of lions from the air, but once they left the Black Hills, we were unable to
determine where they moved or the direction of movement. Luckily, other states and
provinces in the region were happy to provide information on lions traveling through
their areas. Our first experience with this system of information transfer was a call
received from the Oklahoma Department of Wildlife Conservation. They called to
confirm that a lion killed by a train outside of Redrock, Oklahoma, was an animal
collared in the Black Hills (Thompson and Jenks 2005). Because of the distance from
the Black Hills, I asked how they had confirmed that it was an animal from our stud-
ies, and the response was that they had contacted the telemetry com pany (Telonics
Inc.) that had produced the collar, and the com pany confirmed that the serial num-
ber on the radio collar was sold to SDSU. This cat had dispersed 660 miles (1,067 km
straight- line distance) from the last location we had obtained on it in the Wyoming
portion of the Black Hills to the location of its death in Oklahoma.
Since that first confirmed dispersal, we were able to document lions moving from
the Black Hills to North Dakota and northern Minnesota, to Nebraska along the
Niobrara River, to northwestern South Dakota, to the Yellowstone River in central