ABSTRACT 



Twenty-three roadside bird transects were run once during late May-early July 1998 or 

 1999 to document bird presence and relative abundance on and near BLM lands mostly in 

 Petroleum County (20 routes) and adjacent Fergus County (3 routes). Routes tended to be run in 

 morning (n = 16), but some (n = 7) were run in the afternoon to increase coverage as weather 

 permitted. Each roadside transect consisted of 10 survey stops or point counts (one route 

 consisted of 7 stops), spaced 0,5 miles apart. At each stop counts were conducted for 3 min 

 during which all birds detected within a radius of 150 m were recorded. Gross vegetative land 

 cover associated with each point was also recorded. 



Low-stature sagebrush {Artemisia tridentata, often < 0.5 m tall) was classified as the 

 dominant cover type at 1 73 points (76.2%) of all 23 routes (on only two routes was this dominant 

 at < 5 points). Mixed grassland/cropland/pasture was dominant at 34 points ( 15.0%) of 14 

 routes, and ponderosa pine {Pitius ponJerosa) savanna was the dominant cover type on 20 points 

 (8.8%) of 5 routes. Each vegetation type was present at additional points to various degrees, and 

 influenced the presence of some bird species at particular counts. 



Fifty-eight bird species were detected, of which three species occurred on more than half 

 of the point counts: Western Meadowlark (97.4%), Vesper Sparrow (85.9%), Lark Bunting 

 (61.2%). Two species considered sagebrush obligates. Brewer's Sparrow and Sage Thrasher, 

 were detected on 27,3% and <1 .0% of the point counts, respectively. The relatively low 

 abundance of Brewer's Sparrow coupled with the high abundance of Vesper Sparrow and Lark 

 Bunting indicates that low-stature sagebrush cover is often of medium to low density and 

 intermixed with a significant over of grasses However, abundance of Brewer's Sparrow was 

 probably underestimated because of the number of point counts conducted in early July, by 

 which time this species was probably less vocal. Sage Thrashers use taller and denser sagebrush, 

 which was relatively rare along the routes, and their very low abundance is a reflection of the 

 scarcity of suitable habitat. Other species often associated with grasslands were detected on 

 relatively few point counts: Upland Sandpiper (9.3%), Long-billed Curlew (< 1.0%), Short-eared 

 Owl (<1.0%), Sprague's Pipit (<1 0%), Savannah Sparrow (4.4%), Grasshopper Sparrow (9.7%), 

 Baird's Sparrow (<1 .0%). Brown-headed Cowbird was detected on 13,2%o of the point counts, 

 usually in the presence of cattle or pasture. 



The BLM lands in the survey area are dominated largely by low-stature sagebrush, and 

 provide an opportunity to manage especially for some sagebrush obligate species. Sage Grouse 

 were not detected, but special surveys for this species merit consideration Grassland species 

 such as the regionally endemic Sprague's Pipit and Baird's Sparrow, of special concern for a 

 number of land management agencies, do not currently occur in the area in significant numbers 



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