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Description: |
96 leaves, bound : illustrations ; 29 cm |
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Dissertation Note: |
M.S. Oregon State University 1987 |
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Bibliography Note: |
Includes bibliographical references. |
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Summary, Etc. Note: |
Abstract: Home range and habitat use by pileated woodpeckers (Dryocopus pileatus) were studied in the Coast Ranges of western Oregon. Radio-telemetry was used to determine home ranges of 11 woodpeckers and habitat use of 14 woodpeckers after young had fledged during summers from 1982 to 1985. Home range size for individual bird averaged 480 ha; home ranges for pairs of birds were larger. Home ranges were larger than those reported in other studies. The larger home range sizes effectively reduce minimum snag densities calculated with formulas based on densities of birds. There was some overlap (11-160 ha) between adjacent home ranges. Pileated woodpeckers preferred forest habitat classes older than 40 years of age and deciduous riparian habitats for foraging and other diurnal activities. Nesting and roosting occurred in forest stands older than 70 years of age. The amount of foraging habitat within the home ranges averaged 306 ha; the amount of nesting and roosting habitat averaged 200 ha. Because pileated woodpeckers use immature forest stands for foraging they may not be a good "indicator" species for mature forest habitats. Characteristics of 15 nest and 13 roost trees (live and dead) and sites were measured from 1983 to 1986; characteristics were compared to those from other studies. Mean dbh differed significantly (P<0.05) between nest trees (68.9 cm) and roost trees (118.2cm). Trees used for nesting and roosting were taller than 11.5 m. A typical nest or roost tree had a broken top and retained most of the bark. Forest characteristics within a 0.3 ha circular plot at nest and roost sites were highly variable between sites. Discriminant analysis did not reveal a significant (P<0.05) difference between nest and roost sites found within 70- to 100-year-old stands and 100- to 200-year old stands. Mean dbh of nest trees was smaller, mean height of nest trees (26.5 m) was intermediate, and mean height of nest cavities (20 m) was higher than those reported from most other studies. Measured forest characteristics at nest sites were very different between studies because of differences in forests in terms of species composition, site productivity, climate and amount of disturbance. Findings were consistent with a previously recommended "minimum" dbh for pileated woodpecker nest trees of 63.5 cm (with bark). However, provision of nest trees with average characteristics would enhance management schemes which are directed toward minumum population numbers and a minimum amount of reserved habitat |
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Other Forms: |
Also available on the World Wide Web. |
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Elect. Loc./Access: |
http://hdl.handle.net/1957/40176 Connect to this title via ScholarsArchive@OSU |