REV10501

• Permit No: C1981071
• IBM Index Class Name: Revision
• Doc Date: 4/6/1987
• Doc Name: Final Report Bird-Vegetation Associations
• Type & Sequence: PR1
• Media Type: D
• Archive: No

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page-3
` micro-environment beneath its canopy. This rating was not
given to any plants in this study.
4: Species which are codominant in the aspect of the
layer. This is the species which shares dominance with
another or which is subordinate only to the layer dominant
which rates a 5. A layer may thus have one or more
species rating a 4. In stands lacking an outstanding
dominance, the two (or rarely more) most important species
may be assigned a 4 dominance rating if they are
approximately equal in their apparent impact on the
micro-environment.
3: Species which are easily seen by standing in one place
and looking casually around.
2: Species which can be seen only by moving around in the
stand or by looking intently while standing in one place.
Species occurring in patches encountered only by moving
about would be rated a 2 although within the patch the
species may rate a higher dominance value.
1: Species which can be seen only by searching for them in
and around other plants. Species which occur in extremely
widely scattered and isolated patches would rate a 1
provided they did not represent an inclusion of a
different plant community.
These dominance ratings are subjective and do not provide
data that can be interpreted as forage production. For the
purpose of this paper a dominance factor was obtained for
each habitat type. Dominance ratings are a means of the rankings
for all plots in each of the four habitats. This numerical value
probably reflects the diversity of understory vegetation rather
than production.
BIRDS
Two transects were established in each of six vegetative
categories with varible circular-plots placed at > 300 feet apart
along the transects (Reynolds et al. 1980). Birds were counted
three times on each plot from June 4-21, 1985, and June 3-20,
1986. Surveys were started at sunrise and lasted for 3 to 4
hours. Flags were placed 50 feet from the observations at four
directions to assist the observers in estimating distances of
singing and observed birds. Sixteen circular plots were
established in each of the aspen, reclaimed interior aspen, and
mountain shrub vegetative types. A reduced number of plots in
the edge habitats was necessary because of availability. Aspen
edge consisted of 12 and 13 circular plots while reclaimed edge
consisted of 9 and 10 circular plots. Only those birds that were
perched were used in density calculations, although birds that
flew over the survey plots were recorded and listed on the tables
as being present.
Bird densities were determined with a computer program
written by Russell Scott (Colorado State University) which
calculated accumulated bird densities at various distances from
the observation point. Bird densities were calculated at l0-ft.