Other Habitat Groups
Specialized Habitats: Cliffs, Rock Outcrops, and Canyons
Cliffs, rock outcrops, and
canyons are unique habitats that lend topographic diversity to homogeneous
areas. These habitats may only occupy a
small percentage of the land base, but they are disproportionately important as
wildlife habitat. They benefit birds
directly by providing shelter and nesting sites, and indirectly by providing
diverse vegetation structure. For
example, some shrub species, such as skunkbush sumac, chokecherry, currant, and
juniper, are not found in the shrub-steppe region except in association with
rock outcrops. The stability and
persistence of cliff, rock, and canyon formations encourages the repeated use
of specific areas as breeding habitat by birds.
Birds that use these habitats for nesting are highly specialized and are
more susceptible to loss and degradation of nesting habitat than many other
species because they rely completely on cliffs, rock outcrops, or canyons as
nest sites and because the number of suitable nest sites is finite and
essentially non-renewable. The unique
habitat provided by cliffs, rock outcrops, and canyons and their associated
plant species can result in increased species richness and total avian
densities, and a different avian community during the breeding season compared
with adjacent habitats. Landowners and
managers should be aware of the importance of these habitats to birds and
should carefully evaluate management activities involving disturbance or
alteration of these habitats.
Conflicts related to nesting
birds that use cliffs, rocky ledges, rock outcrops, and canyons include mining,
housing developments, road construction, and recreation (e.g. rock climbing,
hiking, dispersed camping, bouldering, bicycling, and horseback riding). Disturbance to birds can be caused by the
presence of humans, noise, or erosion.
During the last few decades, rock climbing has become more popular and
may have reduced the nesting success of some birds and contributed to changes
in cliff bird communities. Mining and
construction can have negative impacts when they occur at the base or the top
of cliffs, rock outcrops, or canyons.
Gravel quarries may actually remove buttes and cliffs for a source of
rock. Any one of these components, or a
combination, may be sufficient to discourage many birds from using an area or
cause an active nest to fail. Such
disturbance may gradually reduce the number of total sites available. Protect cliff, rock outcrop, and canyon
habitats by limiting their use and development wherever necessary and possible,
and avoid converting cliffs, rock outcrops, and canyons to other landforms.
Enhance habitat for birds
and other wildlife by placing suitable rocks on reclaimed mined land. Rock should be placed in piles of varying
sizes up to 6 feet (2 m) in height; rocks and rock piles should be grouped, as
opposed to evenly scattered, over large areas with approximately 4 rock piles
per acre (9 per hectare) taller than 3 feet (1 m); the minimum area to include
outcrop habitats should be about 2.5 acres (1 ha); and shrub species should be
planted in and around piles to encourage establishment of unique plant
communities.
Priority bird species in Specialized habitats in
Level I:
Peregrine Falcon (cliffs)
Level II:
White-throated Swift
(cliffs and canyons)
Level III:
Golden Eagle (cliffs)
Prairie Falcon (cliffs)
Rock Wren (rock outcrops)
Canyon Wren (canyons)
Black Rosy-Finch (cliffs)
Brown-capped Rosy-Finch
(cliffs)
Beidleman, C. A.
2000.
Hamann, B., H. Johnston, P. McClelland, S. Johnson, L.
Kelly, and J. Gobielle. 1999. Birds.
Pages 3.1-3.34 in G. Joslin and H. Youmans, coordinators. Effects of Recreation on Rocky Mountain
Wildlife: A Review for
Rumble, M. A.
1987. Avian use of scoria rock
outcrops.
Ward, J. P., and S. H. Anderson. 1988.
Influences of cliffs on wildlife communities in southcentral