the cougar in the santa ana mountain range, california

CHAPTER 3. DISTRIBUTION AND
TRAVEL CORRIDORS
Cougar Habitat in the Santa Ana Mountain
Range
Using the 5 criteria listed at the end of
Chapter 1, there was about 2070 km2 ·(800
mi 2 ) of cougar habitat in the Santa Ana
Mountain Range during 1988-1992. We obtain
the same estimate by computing the area within
a polygon enclosing all cougar locations. The
largest uncertainty in this estimate concerns
over 50 km 2 of land in and around the Santa
Rosa Plateau that had a mix of orchards, lowdensity
housing, and semi-open pasture. These
areas were included in our estimate on the basis
ofdocumented cougar use (usually brief visits).
However, much of this area was clearly
marginal habitat, and will become unusable if
human use intensifies.
Cougar Use ofCounty Parks East ofl-5
All major regional parks east of 1-5
were cougar habitat. Caspers Wilderness Park,
Limestone Canyon Regional Park, Whiting
Ranch Regional Park, Wagon Wheel Regional
Park, Weir Canyon Regional Park (proposed),
Irvine Regional Park (including the Villa Park
impoundment) and O'Neill Regional Park
(including the Arroyo Trabuco) were all used
regularly by radio-tagged adult cougars. Each
of these 7 parks was an important part of the
home range of at least 1 radio-tagged adult
cougar.
In addition, Peters Canyon Reservoir
Regional Park and Santiago Oaks Regional
Park were both used by subadult radio-tagged
cougars, although we never documented use by
any adult cougar. Only one cougar (M5) used
Peters Canyon Reservoir. He first encountered
and used the reservoir during his dispersal
explorations, but most of his use of the area
was after he broke his hip and knee in a vehicle
accident. Both M5 and MlOused Santiago
Oaks Regional Park (both after their vehicle
accidents). Although both parks offered
excellent habitat in terms of good native
vegetation, ample woody cover, and ample
prey, each was marginal with respect to
housing density and connectivity (see Chapter
1: habitat use). Both parks were immediately
adjacent to and nearly surrounded by high
density housing tracts, and both had only a
narrow connection to the central block of
habitat. Indeed the only non-urban terrain
adjacent to Peters Canyon Reservoir was an
open grassy area nearly 400 m wide, with only
2 thin stringers of shrubs leading toward larger
suitable habitat. .
Peters Canyon Reservoir will become
unusable by cats ifthe Eastern Tollroad or East
Orange Project is built. Even without these
projects, it will remain marginal and rarelyused
habitat.
In contrast, good riparian vegetation
connects Santiago Oaks Regional Park to Irvine
and Weir Canyon Parks. Santiago Oaks
Regional Park will probably continue to receive
occasional use by cougars, especially by
dispersing juveniles and injured animals.
However, ifthe proposed Eastern Tollroad (and
the tract homes that follow it) isolates Irvine
and Weir Canyon Regional Parks from the
central habitat area to the east, it will remove
cougars from al13 ofthese Regional Parks.
We never documented any cougar use
of Carbon Canyon Regional Park in the Chino
Hills. Nonetheless it did meet all 5 criteria for
cougar habitat, and we believe that it was
occasionally used by cougars during 1988­
1992. It certainly will be potential cougar
habitat as long as cougars remain in the Chino
Hills.