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Diet and nutrition of female sage grouse during the pre-laying period

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Title Diet and nutrition of female sage grouse during the pre-laying period
Names Barnett, Jenny K. (creator)
Crawford, John A. (advisor)
Date Issued 1992-09-04 (iso8601)
Note Graduation date: 1993
Abstract Nutrition effects productivity of grouse. Females that obtain
high nutrient diets in spring produce larger clutches and larger, more
viable chicks than hens on less nutritious diets. Grouse select high
nutrient foods to help ensure proper nutrition. Reduced productivity
accounted for the decline of sage grouse (Centrocercus urophasianus)
populations in Oregon since the 1950s. Summer and fall diets of sage
grouse are well described, but no information is available on foraging
ecology or diet of hens during the breeding season. The objectives of
this study were to determine use, availability, and nutrient content
(crude protein, calcium, phosphorus) of key foods of pre-laying female
sage grouse. The study was conducted on 2 areas in southeastern
Oregon: Hart Mountain National Antelope Refuge and Jackass Creek.
Female sage grouse were collected for a 5-week period preceeding
incubation (5 March 8 April) 1990-91. Sagebrush (Artemsisa spp.)
was the primary food and composed less of the diet in 1990 (55%) than
1991 (80%). The remainder of the diet was composed of forbs. Desert
parsley (Lomatium spp.), hawksbeard (Crepis spp.), long-leaf phlox
(Phlox longifolia), everlasting (Antennaria spp.), mountain dandelion
(Agoseris spp.), clover (Trifolium spp.), and milkvetch (Astragalus
spp.) were identified as key forbs. Forbs were used in greater
proportion than available, but sagebrush was used less than available.
Availability of forbs was lower in 1991 than 1990.
Samples of sagebrush from sage grouse crops were higher in
crude protein than samples from foraging and random sites, and
nutrient content of sagebrush was lower in 1991 than 1990. Forbs were
higher in nutrient content than sagebrush. Fewer forbs were eaten in
1991 and crude protein, calcium, and phosphorus contents of the diet
were lower in 1991.
Productivity of sage grouse on both areas was lower in 1991 than
1990. Results of this study indicate diet and nutrient intake of hens
during the pre-laying period may influence productivity of sage
grouse.
Genre Thesis/Dissertation
Topic Sage grouse -- Oregon -- Nutrition
Identifier http://hdl.handle.net/1957/35978

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