To: Field Supervisor, Rawlins Field Office, Bureau of Land Management.

From: Stephen J. Dinsmore, Department of Wildlife and Fisheries, Mississippi State University, Box 9690, Mississippi State, MS 39762.

Subject: Rawlins RMP scoping comments for the Mountain Plover.

This memo provides detailed comments that I hope will aid decisions regarding Mountain Plover management in the revised Great Divide Resource Management Plan (RMP). I have studied breeding Mountain Plovers in Montana since 1991, have surveyed for Mountain Plovers across much of their present breeding range, and have published and continue to publish the results of my on-going plover research in the peer-reviewed literature.

The Mountain Plover is a local and declining bird of the western Great Plains and is currently under review for Threatened status under the U. S. Endangered Species Act (U. S. Department of the Interior 1999). It is one of the rarest North American birds with an estimated population of 8,000 to 10,000 individuals (Knopf 1996). Their conservation hinges on the protection of remaining breeding habitat, including prairie dog colonies, and through the use of proactive plover management that protects nesting sites and uses tools such as fire and rotational grazing to enhance other nesting areas.

Mountain Plovers breed primarily in Montana, Wyoming, and Colorado and sparingly in surrounding states as well as Texas and Mexico (Knopf 1996). Mountain Plovers are uncommon breeders in southern Wyoming (Dorn and Dorn 1999), although there have been no formal surveys in Wyoming to estimate spatial variation in abundance. The Great Divide Resource Area includes at least 2 well known plover breeding areas: the Laramie Plains area in Albany County and the Mexican Flats area in Carbon County. Both areas support at least moderate numbers of breeding plovers, and current research is focusing on estimating plover numbers in these and other areas of Wyoming. Relative to other breeding areas, less is known about Mountain Plovers breeding in Wyoming. Thus, the following comments are based on a review of published literature on Mountain Plovers with an emphasis on studies conducted in Wyoming.

Specific points for your consideration in the revised Great Divide RMP include:

1. Annual surveys. There is a clear need for conducting annual surveys for nesting Mountain Plovers throughout the Great Divide Resource Management Area. Surveys are needed to estimate abundance of plovers within this region, and will provide data necessary to assess future fluctuations in plover numbers. Surveys should be designed to understand distribution and abundance during the nesting and brood-rearing seasons, and could secondarily address issues such as habitat use, differences between nesting and brood-rearing habitat, and other topics of interest. Future impacts to plovers resulting from actions in the Great Divide Resource Management Area cannot be fully measured without a thorough understanding of plover distribution and abundance.
2. Landscape requirements for maintaining Mountain Plovers. The specific requirements for maintaining viable numbers of Mountain Plovers within the Great Divide Resource Management Area are unknown, although they include several important criteria. The Mountain Plover is a disturbed-prairie or semi-desert species (Knopf and Miller 1994) and is characterized as a breeding bird of high plains and desert tablelands (Graul 1975, Knopf 1996). They prefer disturbed habitats for nesting, including areas occupied by prairie dogs (Cynomys spp.; Knowles et al. 1982, Samson and Knopf 1994, Knopf 1996). Mountain Plovers selectively nest on active prairie dog colonies, especially those of black-tailed prairie dogs (Knowles et al. 1982, Olsen-Edge and Edge 1987, Dinsmore 2001), but also occasionally those of the white-tailed prairie dog (C. leucurus) (Ellison-Manning and White 2001a). In many parts of Wyoming, including the Great Divide Resource Management Area, plovers nest in semi-desert habitats on high tablelands, generally in areas dominated by Atriplex spp. and Artemisia spp. (Parrish et al. 1993, Knopf 1996). All sites used by nesting plovers range-wide include short vegetation (typically <5 cm; Graul 1975, Olsen and Edge 1985, Parrish et al. 1993, Ellison-Manning and White 2001b), a bare-ground component (typically >30%; Knopf and Miller 1994), some history of disturbance (e.g., grazing or fire; Day 1994, Olsen and Edge 1985, Knopf 1996, Ellison-Manning and White 2001a), and flat or gently sloping landscapes (Graul 1975). Minimum-area requirements for plover broods have been estimated at 28 ha (Knopf and Rupert 1996), but similar requirements for adult plovers are unknown. Given this information, management for plovers within the Great Divide Resource Management Area should emphasize their preferred habitats (using the above criteria). The number of Mountain Plovers necessary to maintain a viable population within the Great Divide Resource Management Area is unknown, and it is likely that this is not even a discrete population of plovers. I recommend that these landscape-level questions (e.g., minimum viable population size) be the focus of future research.
3. Population trends. There have been no formal surveys to estimate trends in Mountain Plover numbers within the Great Divide Resource Management Area, either from Wyoming Game and Fish Department files or from the published literature. At a larger spatial scale, Breeding Bird Survey (BBS) data for all of Wyoming indicate a non-significant negative trend (-2.37, P = 0.51) for the period 1966 to 2000 (Sauer et al. 2001). However, BBS data are subject to many sources of bias and should be interpreted with caution (see Link and Sauer 1998). Thus, there is weak evidence for a long-term negative trend in plover numbers in Wyoming, but trends at more localized scales are unknown.
4. Habitat quality trends in the Great Divide Resource Management Area. There have been no detailed surveys of Mountain Plover habitat within this region, and specific factors that contribute to quality nesting habitat for this species are unknown (but see #2 above for general characteristics of nesting sites). I recommend you conduct a designated survey for plover nesting habitat, using the criteria listed in #2 above, to provide valuable future baseline data.
5. Relationship between habitat quality and predation. The revised Great Divide RMP should continue to emphasize providing plover nesting habitat that meets the criteria listed in #2 above. The specific relationship between habitat quality and susceptibility to predation (nests, chicks, and/or adults) is unknown for the Mountain Plover. Plovers nesting in native habitats such as prairie dog colonies in Montana experienced high nesting success for a ground-nesting bird; nesting success varied temporally within the nesting season and was negatively impacted by rain events, but neither of these relates to habitat quality (Dinsmore 2001). No other nesting studies, nor any brood or age-specific survival study, have examined the relationship between habitat and susceptibility to predation. The potential impacts of human development projects such as drill pads and additional roads on plovers are many, and could potentially alter the predator regime such that plovers are negatively impacted. Such development could enhance habitat for several potential plover predators (several birds of prey, Black-billed Magpie and other corvids, and several species of mammals), thus negatively impacting plovers. If the revised Great Divide RMP includes provisions for providing less than optimal plover nesting habitat, then managers may indirectly promote plover exposure to additional predators that favor these human-disturbed areas.
6. Existing Bureau of Land Management documents (e.g., existing Great Divide RMP and the Seminoe Road Coalbed Methane EA) specifically address possible impacts and subsequent mitigation measures for Mountain Plovers. After a careful review of these documents (especially U. S. Department of Interior 2001, Appendix E), I recommend the following for consideration in the revised Great Divide RMP:
   1. Annual surveys should be conducted during the period 15 April to 15 June; the earlier start date is needed to better detect plovers before they begin nesting.
   2. Activity delay times of 37 days (active nest) and 7 days (brood) seem adequate given this species nesting cycle and the precocial nature of the chicks.
   3. Important plover nesting areas should receive full protection from development activities. I am concerned that existing documents permit plover nesting and/or brood areas to be impacted/destroyed, without a provision promoting their long-term persistence. Some quality nesting/brood-rearing sites may not be used every year, and in years when they are not used they can be legally and negatively impacted without regard to their overall importance to nesting plovers. The emphasis on plover use areas, defined on an annual basis, is simply too weak to favor the long-term persistence of plovers in this area. I recommend that you define 2 levels of plover use: 1) areas of plover concentration, which I define as sites used by plovers =3 years in a 5-year period, or sites with =5 pairs of plovers in any given year, and 2) sites that are used infrequently, which includes sites that are occupied by plovers <3 years out of any 5-year period, and those sites with <5 pairs in any year. The former sites should receive full protection, perhaps in the form of an Area of Critical Environmental Concern (ACEC) designation, while the latter sites could be developed, with no surface occupancy (NSO) restrictions, if absolutely necessary. I recommend a no surface occupancy buffer zone of a minimum of 0.25 miles around such sites.
   4. I strongly recommend that, whenever possible, you seek to avoid surface disturbance during mining operations. No surface occupancy drilling is an alternative to surface disturbance, and would ameliorate some of the negative effects of drilling operations on Mountain Plovers.
   5. Areas with white-tailed prairie dogs should be withdrawn from surface development and should only be developed under no surface occupancy drilling. I recommend the same no surface occupancy buffer zone (a minimum of 0.25 miles) around these areas. Areas with prairie dogs represent a high quality habitat for nesting plovers (Olsen and Edge 1985, Dinsmore 2001) and should receive special protection. I also recommend you consider enhancing prairie dog numbers within this region, specifically to provide high quality plover nesting habitat.
   6. Future construction/site preparation should include measures to minimize or avoid building structures (fence posts, phone poles, etc.) that can serve as avian predator perches.
7. Long-term effects assessment. Predicting the possible long-term effects of Great Divide RMP management actions to Mountain Plovers poses many challenges. Any such assessment will require detailed information on annual surveys and yearly estimates of nesting and fledging success. Using these yearly estimates, long-term patterns exhibited by plovers can be formally assessed using trend analyses on, for example, the number of breeding plovers. Such analyses will only be meaningful over a "long" time period, preferably >5 years. At this time, I see no strong need for a formal meta-analysis because baseline data are simply not available for key life history components of Mountain Plovers such as brood survival and geographic variation in age-specific annual survival. I do, however, support such an analysis at present if it is used in an exploratory fashion to suggest areas where information is lacking or where future efforts should be expended. When detailed baseline information eventually becomes available, a formal meta-analysis on annual survival and/or annual reproductive success would be useful. Modeling exercises to assess the possible impacts of extreme weather events on local plover numbers are not recommended at this time because baseline data necessary for such models are not yet available.
8. Mitigation. Plover nesting areas will continue to require some protection from disturbance during the nesting season, and in no way do I endorse mineral development in plover concentration areas within the Great Divide Resource Management Area. Plovers frequently nest near areas of human disturbance, including roadways, drill pads, and other forms of human disturbance (Knopf 1996, Ellison-Manning and White 2001a), although their success in these areas relative to other native habitats has not been evaluated. In areas of plover concentration (see definition in #6c), I recommend that there be no development; these sites should be off-limits to ensure that quality nesting areas receive long-term protection. At other sites (e.g., those used infrequently by plovers; see definition in #6c), the following mitigation measures should be followed. Plover nesting areas should be protected by a 100m buffer during the nesting season (10 April to 10 July), a 0.25 mi construction buffer should be placed on all nesting sites, the 200m active nest buffer, specific restrictions on construction of possible avian predator perches, and road and driving restrictions, as outlined in the Decision of Record (U. S. Department of the Interior 2001). Mitigation should also specifically include provisions for enhancing other nesting habitats used by Mountain Plovers, including prairie dog colonies.

After reviewing all available information on Mountain Plovers that is pertinent to the Great Divide RMP, I offer the following 3 recommendations for future monitoring and information needs:

1. Any monitoring of Mountain Plovers should be conducted using accepted survey methodology. Survey design considerations should include the random selection of areas to be surveyed, surveys that minimize roadside bias (e.g., do not conduct only road-based surveys), incorporation of distance sampling theory to estimate plover densities and trends (Buckland et al. 2001), and conducting surveys during the pre-nesting period (mid-April to mid-June) when plovers are most visible. Surveys should also stress obtaining adequate sample sizes for analyses, although the small number of plovers may limit this goal.
2. Adaptive resource management. This strategy should be incorporated into the management of plovers in the Great Divide Resource Management Area as follows. First, reliable estimates of plover numbers in this area are needed. Second, based upon these estimates and the results of nest and brood monitoring, managers will have the flexibility to adjust their activities to meet changes in the status of plovers in this area. Third, managers will need to specifically monitor plover response to management activities so that management can be "adaptive".
3. In my opinion, critical information needs include a rigorous estimate of the number of Mountain Plovers nesting in the Great Divide Resource Management Area, an understanding of how productivity varies between disturbed and undisturbed sites, and how human activities specifically impact plover nesting success and chick survival in areas of mineral development.

Buckland, S. T., D. R. Anderson, K. P. Burnham, J. L. Laake, and D. Borchers. 2001. Introduction to distance sampling: estimating abundance of biological populations. Oxford University Press, London.

Day, K. S. 1994. Observations of Mountain Plover (Charadrius montanus) breeding in Utah. Southwestern Naturalist 39:298-300.

Dinsmore, S. J. 2001. Population biology of Mountain Plovers in southern Phillips County, Montana. Ph. D. dissertation, Colorado State University, Fort Collins.

Dorn, J. L., and R. D. Dorn. 1999. Wyoming Birds, second edition. Mountain West Publishing, Cheyenne, Wyoming.

Ellison-Manning, A. E., and C. M. White. 2001a. Breeding biology of Mountain Plovers (Charadrius montanus) in the Uinta Basin. Western North American Naturalist 61:223-228.

Ellison-Manning, A. E., and C. M. White. 2001b. Nest site selection by Mountain Plovers (Charadrius montanus) in a shrub-steppe habitat. Western North American Naturalist 61:229-235.

Graul, W. D. 1975. Breeding biology of the Mountain Plover. Wilson Bulletin 87:6-31.

Knopf, F. L. 1996. Mountain Plover (Charadrius montanus). In The Birds of North America, No. 211 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D. C.

Knopf, F. L., and B. J. Miller. 1994. Charadrius montanus-montane, grassland, or bare-ground plover? Auk 111:504-506.

Knopf, F. L., and J. R. Rupert. 1996. Reproduction and movements of Mountain Plovers breeding in Colorado. Wilson Bulletin 108:28-35.

Knowles, C. J., C. J. Stoner, and S. P. Gieb. 1982. Selective use of black-tailed prairie dog towns by Mountain Plovers. Condor 84:71-74.

Link. W. A., and J. R. Sauer. 1998. Estimating population change from count data: application to the North American Breeding Bird Survey. Ecological Applications 8:258-268.

Olson, S. L., and D. Edge. 1985. Nest site selection by Mountain Plovers in northcentral Montana. Journal of Range Management 38:280?282.

Olson-Edge, S. L., and W. D. Edge. 1987. Density and distribution of the Mountain Plover on the Charles M. Russell National Wildlife Refuge. Prairie Naturalist 19:233-238.

Parrish, T. L., S. H. Anderson, and W. F. Oelklaus. 1993. Mountain Plover habitat selection in the Powder River Basin, Wyoming. Prairie Naturalist 25:219-226.

Samson, F. B., and F. L. Knopf. 1994. Prairie Conservation in North America. BioScience 44:418-421.

Sauer, J. R., J. E. Hines, and J. Fallon. 2001. The North American Breeding Bird Survey Results and Analysis, 1996-2000. Version 2001.2. USGS Patuxent Wildlife Research Center, Laurel, Maryland.

U. S. Department of the Interior. 1999. Endangered and Threatened Wildlife and Plants: Proposed Threatened Status for the Mountain Plover. Federal Register 64 (30):7587-7601.