the cougar in the santa ana mountain range, california

1991, Logan and Irwin 1985, and Belden et al.
1988). These studies also reported avoidance
of agricultural areas, habitats lacking woody
vegetation, and habitats that provided little
horizontal (hiding) cover.
Topography. Cougars used all types
of terrain, including the steepest slopes and
rock outcrops, and all aspects. During all night
monitoring we documented that cougars hunted,
traveled, and rested in a variety of topographic
situations. We suspect there might also be
some avoidance of flat areas, as reported by
Logan and Irwin (1985) and Laing and Lindzey
(1991), but this would be difficult to document
in our study because almost all flat areas had
been cleared for housing, row crops, or
livestock pastures.
During long distance movements,
cougars seemed to prefer the scour zones in the
bottoms of larger canyons. Dirt roads often
paralleled these zones, and typically a cougar
alternated between walking in the road and in
the wash. Ridgetops were also favored travel
routes, especially when a dirt road or hiking
trail created an easy path through chaparral or
other brushy vegetation. Although the
preference for canyon bottoms and ridgetops
for travel was pronounced, it was far from
absolute; on many occasions cougars trayeled
midslope along a contour line, along the fall
line ofa steep slope, or diagonal to the fall line.
Even when traveling predominantly along a
ridge or wash, cougars made frequent detours
into other topographic situations.
Fire. Radio-tagged cougars
experienced several large fires during the study.
The animals always successfully avoided the
flames. When a fire occurred within a cougar's
home range, the cat usually re-entered the
burned area (or at least the unburned patches
within that area) within 2 weeks after the fire.
For example, on October 18-20 1989, a 9000acre
fire burned portions of Camp Pendleton,
Rancho Mission Viejo, and Cleveland National
14
Forest. The burned area includes large portions
of Talega, San Mateo, and La Paz Canyons,
which are very important parts ofF3's and F4's
home ranges. In the first week following the
fire, both cats avoided the bum area, but started
re-using it within 2 weeks and made extensive
use of the bum within 6 weeks. A similar
patterns of short-term avoidance of bum areas
was exhibited by F11 on Camp Pendleton on 2
occasIOns.
Human use. Radio-tagged cougars
traveled through some rural areas with low
housing density, e.g., Williams Canyon,
Santiago Canyon just west of Modjeska, the
cluster of dwellings on Starr Ranch. Cougars
categorically avoided denser areas such as the
communities of Modjeska, Silverado, and
Trabuco Canyon, although they would skirt
these areas within 100 meters of the peripheral
homes.
It is difficult to specify the housing
density at which cougars will cease to use an
area. Cougars clearly tolerate I dwelling per
40 acres, ifthe area is adjacent to unpopulated
areas. Our best estimate is that the transition
from habitat to nonhabitat occurs at about I
dwelling per 20 acres. Under ideal conditions
(no tall fences, no free-roaming dogs, low-speed
roads, minimal loss of native vegetation, no
goats or sheep to provoke depredation
incidents, tolerant landowners) we suspect that
cougars might tolerate housing densities as high
as 1 dwelling unit per 10 acres.
Habitat Size and Connectivity.
Because cougars have large home ranges and
do not reach high population density, habitat
must be either contiguous with or connected to
at least several hundred square miles of suitable
habitat. Because the undeveloped portion of
the Santa Ana Mountain Range is only about
2070 km 2 (800 mi 2 ), connectivity is critically
important, and loss of connectivity is the main
factor threatening to cause many wildlands to
cease being cougar habitat. For example, the