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Green tailed Towhee, Dave Herr, USFS
Due to high natural resource values and increasing motorized recreational use, the
Bureau of Land Management (BLM) completed a Travel Management Plan (TMP) for the
Wolford Mountain Area in Middle Park, Colorado, to improve soil, vegetation, and
wildlife habitat conditions. To assess impacts of travel management on breeding
bird species, Rocky Mountain Bird Observatory (RMBO) initiated a study in 2005 comparing
bird densities in areas with road closures to areas where roads remain open. In
2006, RMBO completed a second year of surveys to strengthen the baseline assessment.
This report gives the analysis of 2006 data and provides a comparison to 2005 data.
RMBO established bird survey locations in sagebrush habitat, to compare bird abundance
along county roads, open local roads, local roads closed under the TMP, and interior
areas greater than 125 m from all roads. Because the BLM is also interested in avian
use of their riparian areas, RMBO also established twenty bird survey points along
Muddy Creek and seven points in Cow Gulch. RMBO also measured vegetation at bird
survey points, because differences in vegetation affect bird use.
In 2005, RMBO conducted 208 point-count surveys at 146 survey points, detecting
1468 individual birds of 72 species. In 2006, RMBO conducted 257 point-count surveys
at 144 points, counting 1856 birds of 67 species. In 2006, eleven avian species
were added to the species list compiled in 2005. RMBO measured vegetation at 37
points in 2005 and 54 points in 2006.
The overall numbers and species richness of birds at survey points was slightly
greater in 2006 than in 2005. However, the densities of the Green-tailed Towhee,
Sage Thrasher, and Vesper Sparrow in sagebrush were slightly lower than in 2005.
There was no effect due to road type or distance from roads on avian species richness
and densities of the four most common sagebrush species in either year. The Horned
Lark was found to be more abundant near all road types in comparison to points located
away from roads. The average number of birds surveyed, avian species richness, and
three of four bird species were negatively associated with rocky areas. In addition,
each focal species showed a unique response to shrub characteristics, suggesting
habitat partitioning among the primary sagebrush species.
Sagebrush was the dominant shrub found, representing an average of 70-89% cover
(2005-2006, respectively). The ground layer was comprised of litter (32%), grass
(24%), bare ground (21%), shrubs less than 0.2 m tall (11%), forbs (8%), and rock
(5%).
This baseline survey provides a solid foundation for the monitoring of bird responses
to travel management in the Wolford Mountain Project Area.
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Contact:
Alison Cariveau
Alison.Cariveau@rmbo.org
State: Colorado
Funder: Bureau of Land Management and Colorado Division of Wildlife
Materials:
Wolford Mountain 2006 Final Report.pdf
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