In Oregon, sage grouse (Centrocercus urophasianus) were common in the
eastern portion of the state. Since 1940 populations declined because of
decreased productivity. The western subspecies (C. u. phaios) was listed as a
candidate for threatened and endangered status in 1985 because of declines in
Oregon and Washington and extirpation from British Columbia. Habitat
availability and habitat condition were factors associated with impaired
productivity. Stand structure and forb availability were characteristics most
associated with habitat selection by hens with broods. The objectives of this
study were to determine habitat use and selection by hens with broods and the
relationship between food availability, habitat use by hens, and diets of
juvenile sage grouse. Of the 2 study areas used, Hart Mountain had greater
long term productivity and abundance than Jackass Creek. Use of cover types
and habitat components were compared within and between study areas.
In this study, sage grouse hens selected low sagebrush (Artemisia sp.)
cover types during early brood-rearing then switched to use of big sagebrush
cover types during late brood-rearing. In general, cover types used
selectively had greater availability of forbs, and changes in forb
availability within cover types from early to late brood-rearing corresponded
to changes in cover type use. Differences in forb availability between study
areas may have affected productivity. Hens at Jackass Creek selected sites
with forb cover similar to that available to broods at Hart Mountain and home
ranges were larger at Jackass Creek. Furthermore, diets of juvenile sage
grouse were higher in forbs and insects at Hart Mountain. Larger home ranges
and less nutritious diets were potentially responsible for lower productivity
at Jackass Creek. Results indicated that management to improve brood habitat
should focus on maintenance of cover type diversity and availability of forbs. / Graduation date: 1993
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/36471 |
| Date | 29 June 1992 |
| Creators | Drut, Martin S. |
| Contributors | Crawford, John A. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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