Sampling in rugged terrain

Edited by:
C. John Ralph and J. Michael Scott


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Work in rugged terrain poses some unique problems that should be considered before research is initiated. Besides the obvious physical difficulties of crossing uneven terrain, topography can influence the bird species? composition of a forest and the observer's ability to detect birds and estimate distances. Census results can also be affected by the slower rate of travel on rugged terrain. Density figures may be higher than results obtained from censuses in similar habitat on level terrain because of the greater likelihood of double-recording of individuals and of recording species that sing infrequently. In selecting a census technique, the researcher should weigh the efficiency and applicability of a technique for the objectives of his study in light of the added difficulties posed by rugged terrain. The variable circular-plot method is probably the most effective technique for estimating bird numbers. Bird counts and distance estimates are facilitated because the observer is stationary, and calculations of species? densities take into account differences in effective area covered amongst stations due to variability in terrain or vegetation structure. Institution of precautions that minimize the risk of injury to field personnel can often enhance the observer?s ability to detect birds.

Additional publication details

Publication type:
Book chapter
Publication Subtype:
Book Chapter
Sampling in rugged terrain
Series number:
Year Published:
Cooper Ornithological Society
Publisher location:
Lawrence, Kansas
Contributing office(s):
Patuxent Wildlife Research Center
x, 630
Larger Work Type:
Larger Work Subtype:
Other Government Series
Larger Work Title:
Estimating Numbers of Terrestrial Birds
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Last page: