Opinion by Brian Jensen
Sage Grouse: Why the Focus on Nesting Habitat?
By Brian Jensen, State Wildlife Biologist, USDA Natural Resources Conservation Service
In recent years, sage grouse and their habitats have received a lot of attention across Wyoming and the West, but even more recently some folks have been questioning why the bulk of that attention has been focused on sage grouse nesting habitat rather than other seasonal ranges.
In a similar light, there has been some questioning whether government programs, such as the Natural Resources Conservation Service’s Sage Grouse Initiative and the Wyoming “Core-Area Strategy,” are too narrow in their focus and management recommendations.
While it is true that sage grouse, and many other species, do have other distinct seasonal ranges that are required to maintain populations, generally, the “science” of sage grouse supports efforts to protect and improve nesting habitat over other habitats. But fortunately, it is often possible to maintain or improve other seasonal habitats while focusing on nesting habitat.
Preventing full listing
Unless you live on a very isolated ranch, you are probably aware that sage grouse have been designated as “warranted, but precluded” by the U.S. Fish and Wildlife Service under the Endangered Species Act due to their precipitous decline over the last 60 years or so. “Warranted but precluded” essentially means there is scientific evidence to suggest that a species needs protection under the Endangered Species Act, but the listing of other higher priority species takes precedent. Under a warranted but precluded designation, the species’ status is reviewed annually.
Because of this designation, there are many efforts at the local, state and national levels to prevent a full listing that could bring a major burden to Wyoming’s economy. Some of those efforts are targeted within set distances from leks or sage grouse breeding areas as extensive Wyoming research has shown that 64 percent of sage grouse hens nest within 3.2 miles and 80 percent within four miles of a lek. Further, range-wide population modeling based on collared bird data indicates that nest success has the greatest influence on the variability in population growth rate. Adult female and chick survival are also very important. Range-wide nest success has averaged 45 percent, indicating room for improvement.
Successful nest sites
Many of the same studies mentioned above have compared the characteristics of successful and unsuccessful sage grouse nests. Nest sites on the whole were in locations with greater sagebrush canopy coverage, residual grass height and residual grass cover than average. Residual grass is grass remaining following the grazing season. It is very important for the concealment of nests associated with ground nesting birds that establish nests before the current year’s growth has begun. The cover provides protection from predators – those that use sight as well as smell. Successful nest sites had greater residual grass height and cover than unsuccessful nests. From such studies, it has been determined that simply increasing residual grass height by a few inches could increase nest success by 10 to 15 percent, which could be significant to the long-term viability of the bird.
“But what about those big groups of birds I see during the late summer or winter periods?” you might ask. “Aren’t the habitats they use important?” Most definitely, they are. They just may not be as limiting on a population level as nesting areas. Although sage grouse may be congregated on a relatively small percentage of the landscape during late brooding, fall and winter, survival is usually high during these periods, with winter usually being the highest. Sage grouse have actually been documented to gain weight during the winter, eating exclusively sagebrush leaves! Since these areas are limited in size, efforts are underway to identify high sage grouse concentration areas, particularly winter areas, and protect them. Largely, this means maintaining dense sagebrush stands and sagebrush located on windblown areas that are available during heavy snow events. Efforts to improve areas that stay moist during the late summer and serve as late brood rearing habitat would also be beneficial. This could include efforts to restore wet meadows, streams, or associated habitats.
Other benefits of improved nest areas
While sage grouse do have distinct seasonal habitats, efforts targeted at improving nesting habitat are unlikely to be a detriment to other habitats. The primary tool used under the Sage Grouse Initiative is prescribed grazing, tailored to needs of the individual ranch, to meet rangeland health goals and increase residual grass heights. It is not a one-size-fits-all approach.
In addition to improving nest success, increased residual heights should help maintain soil moisture, which should, in turn, increase forbs on the landscape and increase water infiltration. Increased infiltration will ultimately slow the water cycle down and keep the landscape greener longer and maintain wet areas (i.e. late brood-rearing areas) later into the summer.
None of the grazing management recommendations should lead to a marked decrease in sagebrush abundance in any area and should thus maintain winter habitat. In some locations, efforts are actually underway to restore or increase the amount of sagebrush that may have been lost due to wildfire or farming activities to make areas desirable for both grouse nesting and wintering.
Ranchers are key to success
Finally, despite all the attention placed on grazing management to improve sage grouse habitat, it bears repeating that grazing activities were not one of the primary reasons for the current listing status of the sage grouse. The primary cause for listing was habitat loss and fragmentation, two things that are a detriment to both agricultural producers and sage grouse.
These threats to sage grouse habitat are why the increased use of conservation easements has been such an important tool in the listing fight. Easements permanently protect some of the best remaining sage grouse habitats in the state from future development. Given the bird’s tendency to return to the same areas year after year, and the difficulty in restoring arid landscapes, maintaining good habitat may be the most powerful tool in our toolbox. However, to keep this bird from becoming fully listed may well require an “all hands on deck” approach that considers all opportunities. But, regardless of the tool utilized, ranchers will be key to their success.