Preference of wintering sage grouse for big sagebrush.

Abstract

A study determined sage grouse (Centrocercus urophasianus) preference for 3 subspecies and 9 accessions of big sagebrush (Artemisia tridentata Nutt.). The subspecies were mountain big sagebrush (A.t. ssp. vaseyana Rydb. Beetle), Wyoming big sage-brush (A.t. ssp. wyomingensis Beetle and Young), and basin big sagebrush (A.t. ssp. tridentata Nutt.). Accessions were collected at various sites in Utah and established in a uniform garden. Eleven plants for each accession or 33 plants for each subspecies were planted at random on a 2.13-m grid for a total of 99 plants. An enclosure with a top was constructed. Six birds were captured and placed in the garden. Preference was measured by the number of bites taken during the study and by estimates of percentage of leaves eaten at the end of the study. Results, by order of preference, were mountain big sagebrush, Wyoming big sagebrush, and basin big sagebrush. Within the most preferred subspecies there was distinct preference among accessions as measured by bite counts. When the forage of preferred subspecies or accessions was exhausted, the birds readily ate other subspecies or accessions.