(This summary was written and posted by the Bureau of Land Management - http://www.blm.gov/wy/st/en/info/news_room/2007/07/03sagegrouse.html)

Findings of Dr. Naugle and other researchers within the Powder River Basin in Wyoming include:

• Male lek-count data show the region-wide sage-grouse population declined by 84% from 1988-2005. In 1990-1995, severe population declines occurred prior to the onset of energy development. After the onset of coalbed natural gas (CBNG) in 1997, the pace of development increased rapidly. From 2000-2005, sage-grouse populations in CBNG declined by 86%, (-33% per yr), whereas populations outside CBNG declined by 35% (-8% per yr).
• Among leks of known status in 2004-2005, only 38% remained active within CBNG fields, compared to 86% of leks adjacent to or outside CBNG fields. From 2000-2005, leks in CBNG fields had 11-55% fewer males per active lek than leks outside CBNG development. All known remaining leks with =25 males occurred outside CBNG fields in 2005.
• Findings show that CBNG development is having negative effects on sage-grouse populations over and above those of habitat loss caused by wildfire, sagebrush control, or conversion of sagebrush to pasture or cropland. Moreover, the extent of CBNG development explained lek inactivity better than power lines, pre-existing roads, or West Nile virus mortality.
• Research findings show a lag effect, with leks predicted to disappear, on average, within 4 years of CBNG development. Intensive monitoring also allowed researchers to estimate the precise timing of lek disappearance relative to CBNG development. Regardless of other stressors, lek complexes did not go inactive until after CBNG development came into the landscape.
• The current density of CBNG development (80-160 acre spacing) is 3-6 times greater than the level that sage-grouse can tolerate. Leks typically remained active when well spacing was = 500 acres (1.3 wells per section).
• After controlling for habitat quality, research shows that sage-grouse in winter avoid sites that have been developed for CBNG. The birds are 1.3 times less likely to use otherwise suitable habitat once it’s been developed. Sage-grouse select for sagebrush flats but avoid rugged terrain and coniferous habitats.
• Avoidance of CBNG in winter and the high likelihood of lek loss in spring threaten to severely impact populations along the Montana/Wyoming border where models classify only 13% of area as high quality winter habitat. Options are limited for these populations of non-migratory birds because they rely on the same landscapes to breed, raise broods, and survive the winter.
• Undeveloped winter habitat is more abundant south and east of the city of Buffalo, Wyoming, than north along the border of Montana. Sagebrush here provides winter habitat for birds that nest as far north as 24 miles where winter habitat is poor. Unfortunately, the migratory nature of this population means that separate nesting and wintering grounds need to be conserved if this population is to persist.