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Miles City Field Trip

Miles City Field Trip Notes

June 14, 2004


Photo 2: Pond and cropland near horizon on left side of photo

Anne Cossitt welcomed the group and summarized the purpose of the field trip, which was to identify seasonal sage grouse habitats and assess and discuss habitat conditions. Cossitt handed out copies of Appendix B of the state sage grouse plan, which contains habitat assessment worksheets. Cossitt introduced Kent Undlin, BLM biologist, who organized the field trip and would lead the group.

Field Trip Location

The field trip took place on lands of Ft. Keogh, south of Miles City. Kent Undlin described the area as not prime habitat generally because it lacks wet meadow areas that serve as late brood-rearing habitat. There are 2 or 3 leks in the 40,000-acre area of Ft. Keogh.

Stop 1: Lek Area

The first site on the field trip was a short stop at a lek. Undlin described it as atypical in that there was no nearby sagebrush. The lek area was surrounded by hundreds of yards of open grass. In 1991, 40 birds were counted on this lek; in 1993, there were 38 males; in 1994, 40 males; in 2001, 4 males; and in 2004, 11 males. Lance Vermire, range conservationist on Fort Keogh, indicated that range management had not changed over that period and that the single biggest change factor during that time was drought.

Stop 2: Winter and Breeding Habitat Area

The next stop was a site that served as both winter and breeding habitat. Sage grouse droppings (which have a different shape and texture in winter and spring/summer because of diet) clearly indicated past use in winter. The area included big sagebrush with some silver sagebrush scattered throughout.

The group worked through the "Sage Grouse Habitat Assessment Worksheet-Breeding Habitat" form. The following is a summary of results and discussion that occurred during the assessment.

Cover type: Area was described as "Sagebrush with perennial grassland" (note however that the form only allows one or the other to be "selected").

Average big sagebrush canopy cover: People "eyeballed" the area and came up with different estimates of canopy cover, ranging from 5% to 50%. It was noted that looking at the landscape while on foot or in a vehicle is likely to result in an estimate of canopy cover that is higher than actual, unless the reviewer is experienced in making these estimates. That is because the most accurate measurements are when one is looking straight down, from directly above. (More than one person noted that looking down from horseback is a good way to assess canopy cover.)

The group then did an actual measurement of a 25-foot segment, noting exactly where the tape fell above sagebrush. The measurement indicated a 48% canopy cover, but the group noted that if the measurement had extended another 25 feet, that section would have been primarily open (without any sagebrush canopy). In addition, it was noted that when one looked in one direction, sagebrush appeared prevalent, but when you turned around and looked the other way, there were very few sagebrush. Those participants with several years of experience indicated that they would assess the area from the first viewpoint as being winter habitat and in a general landscape setting (not just a 25-foot or 100-foot area but what appears generally within the larger setting—in this case, likely 20 to 40 acres or more) as probably having about a 15% canopy cover, putting it in the " Suitable Habitat" range on the worksheet. It was noted that it would help if the worksheet indicated guidelines for the area to be measured. Biologists present indicated that research shows that 2/3 of birds nest within 2 miles of a lek, so it is important to look at the landscape level.

To get accurate measurements however, the best way is to use the tape measure. It was suggested that you take the first 100-foot measurement, then spoke out from one end with two other 100-foot measurements for a "Y" shaped measurement. (Note that the worksheets in Appendix B have detailed instructions for line intercept transect and Daubenmire frames, which would be much more detailed and comprehensive than the "measuring tape" method just described.)

It was noted several times throughout the field trip that ranchers are not going to have the time to do these measurements. It was suggested that a field guide book with photographs (from different angles) of various canopy cover densities would be helpful for use by the general public.

Another question that came up was, "What if the area is mixed with silver sagebrush making up half or more of the area? Would you just measure big sagebrush for canopy cover, or would you measure silver sagebrush as well?"

Average big sagebrush height: Kent Undlin and others estimated the height at 24 inches. Measurements were then taken at 6 sites, with a resulting measurement of 24 inches. (Lucky guess for Kent or those summers making thousands of measurements have finally paid off!) This height qualifies as "Suitable Habitat" on the worksheet.

Big sagebrush growth form: Identified for this area as spreading form, with few, if any, dead branches for most plants, putting it in the "Suitable Habitat" category on the worksheet. The group discussed age of the big sagebrush on the site. Most of the bigger plants were estimated to be 30 years or older. There were some smaller plants as well (3 to 4 inches) identified as likely being just a few years old. Participants wondered if age and age diversity shouldn't also be addressed in the habitat assessment worksheet.

Average herbaceous grass and forb height: Participants thought that grass height and forb height should be separated. Essentially there were no forbs on this site at this time. There was a question about residual grasses and if they are measured as herbaceous and if not, should there be a different category. Overall the group felt that there was no way that this area would have a 7-inch average grass height, and yet the grass was in good condition for this area (with lots of taller residual grasses evident). No measurements were made of the grass height.

Average grass canopy cover and Average forb canopy cover: Participants felt these categories didn't make sense to include on the worksheets. For one thing, to actually take the measurements would be time prohibitive. Someone suggested just taking the "negative" measure of bare ground, but another person indicated that areas with club moss, which is also negative, would be included as a positive. Another pointed out that if you combined canopy cover for big sagebrush, grass, and forbs in the "Suitable Habitat" column on the worksheet, you could still have as much as 50% of the area listed as something else (like bare ground), which didn't seem to make sense for suitable habitat.

Overall site evaluation: The group generally identified this as being good, suitable winter habitat, especially given drought conditions. It was suitable breeding habitat, but because of lack of nearby late-brooding habitat, was not the best.

General Observations

The group spent a lot of time discussing how assessments would be done by ranchers/landowners compared to how they might be done by experts or trained volunteers. Generally, the group felt that the former would need something much simpler to use as a guide (such as a guidebook with photos displaying different habitat types and canopy cover densities, or as suggested later by a field trip participant, a graduated scale with 10 being excellent and 0 being totally unsuitable).

It was suggested that the worksheet should include space for discussion of "Desired Future Condition" or "Preferred Future Condition."

Our thanks to Fort Keogh for hosting the field trip!


Doug Campbell
Scott Cassel
Anne Cossitt
Tom Courtney
Ward Jackson
Scott McAvoy
Larry Murphy
Dean Seifert
Corey Swenson
Kent Undlin
Lance Vermire
Phoebe Williams
Todd Yeager