(published 1998)
Habitat Atlas for Wildlife at Risk
Rugged Terrain Ecosystems

The towering cliffs and rocky ridges that frame the South Okanagan and Similkameen valleys are important habitat for many species of birds, mammals and reptiles. Eleven species of Red- and Blue-listed vertebrates are associated with this ecosystem. The precipitous bluffs provide escape terrain for California bighorn sheep, especially important during the spring lambing season. Birds such as Golden Eagles, Peregrine and Prairie Falcons, Turkey Vultures and White-throated Swifts also use cliff ledges and crevices as safe sites to raise their young each year. Many bat species raise their young in carefully selected, sun-warmed crevices, high within cliff faces.

Talus, or scree, is the rocky debris which accumulates at cliff bases. Talus provides good cover for wildlife, especially snakes, lizards, mice and even some birds. Rattlesnakes and night snakes hibernate in deep chambers below the ground in talus and broken rock, while racers and gopher snakes are often seen sunning themselves on the warm rocks in spring. The beautiful, cascading song of the Canyon Wren is heard in Canada only in the South Okanagan, almost always from large talus at the base of high cliffs.

The physical difficulties in altering this rocky, rugged habitat has largely saved it from agricultural and urban developments in the South Okanagan. Rugged terrain is a patchy ecosystem, however, and many examples in the valley have become islands in a sea of cultivated and urbanized lands. This lack of natural movement corridors may result in many species disappearing from isolated patches without an opportunity for recolonization from nearby rock outcrops.

Threats:

• Developments on land adjacent to cliffs can restrict wildlife species' access to escape routes, travel corridors and feeding areas.
• Heavily used rock climbing sites may have an impact on bird nesting and bighorn sheep use for lambing.
• Exploitation of talus for rip-rap.

Wildlife at Risk for which this habitat is critical