Western North American Naturalist Volume 61 Number 2 Article 10 4-23-2001 Nest site selection by Mountain Plovers (Charadrius montanus) in a shrub-steppe habitat Ann E. Ellison Manning Brigham Young University Clayton M. White Brigham Young University Follow this and additional works at: https://scholarsarchive.byu.edu/wnan Recommended Citation Ellison Manning, Ann E. and White, Clayton M. (2001) "Nest site selection by Mountain Plovers (Charadrius montanus) in a shrub-steppe habitat," Western North American Naturalist: Vol. 61 : No. 2 , Article 10. Available at: https://scholarsarchive.byu.edu/wnan/vol61/iss2/10 This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Western North American Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Western North American Naturalist 61(2), © 2001, pp. 229–235 NEST SITE SELECTION BY MOUNTAIN PLOVERS (CHARADRIUS MONTANUS) IN A SHRUB-STEPPE HABITAT Ann E. Ellison Manning1,2 and Clayton M. White1,3 ABSTRACT.—Habitat use by Mountain Plovers was studied in Duchesne County, Utah, from 1996 to 1998. This area is a shrub-steppe habitat and is different from the shortgrass prairie where current Mountain Plover breeding densities are greatest. Mountain Plovers prefer areas of short, sparse vegetation. Habitat surveys quantified vegetation and open space composition at nest and randomly selected sites. Data gathered in 1998 showed significant differences between nest and random sites in maximum vegetation height (P = 0.0021) and percentage total rock cover (P = 0.0027). As per- centage rock cover also reflects open space, these results are consistent with general habitat characteristics preferred by the Mountain Plover. White-tailed prairie dogs were present significantly more often near the 5 nest sites located in 1998 than the 20 random sites. Insects collected from the same nest areas and random points reflected food items known to be in the Mountain Plover diet, but there were no significant differences in diversity of insects between nest and random sites. Key words: Mountain Plover, Charadrius montanus, breeding habitat, Uinta Basin. The Mountain Plover (Charadrius montan- (Knopf and Miller 1994). On the Pawnee us), a species native to grasslands, typically National Grassland, Colorado, Mountain Plovers breeds in open, flat shortgrass prairie. Histori- prefer to nest in areas where mean grass cally, shortgrass prairies were composed of height is <8 cm in April when breeding sites treeless bottoms and uplands vegetated by are being selected (Graul 1975). In California blue grama (Bouteloua gracilis) and buffalo during winter Mountain Plovers strongly grass (Buchloe dactyloides). Bison (Bison bison), select alkaline flats, recently burned fields, pronghorn (Antilocapra americana), and prairie and grasslands which have been heavily grazed. dogs (Cynomys sp.) evolved as the primary Flat, cultivated lands are also used for forag- herbivores on this landscape. Because native ing and roosting (Knopf and Rupert 1995). grasslands have been altered by the removal Knopf and Miller (1994) suggested that Moun- of primary native grazers and by agricultural tain Plovers are a species of disturbed prairie use of the Great Plains, there is less suitable or semidesert, rather than strictly restricted to breeding habitat available, as tall vegetation typical shortgrass prairie. In 1993 surveys con- hinders the ability of this bird to detect preda- firmed a Mountain Plover population, of un- tors (Knopf 1996). As a result of such alterations, known size, breeding in Utah on the Myton native species are declining in number, and Bench, Duchesne County, Uinta Basin (Day exotic species diversity and density are increas- 1994). Prior to 1992 there were 12 documented ing (Knopf 1994). Because of long-term declines, historical sightings of Mountain Plovers in the Mountain Plover was listed as a candidate Utah, and 6 were in the Uinta Basin (Audubon species under the U.S. Endangered Species Field Notes 1966, Waller 1967, White et al. Act on 3 May 1993 and is currently under con- 1983, S. Madsen, BLM, personal communica- sideration for a threatened designation. tion). Observed population numbers have Breeding Mountain Plovers occur geogra- always been small but fairly consistent from phically from Montana south to New Mexico 1993 to 1998 (UDWR 1997). (Knopf 1996). Studies of breeding populations Habitat characteristics in the Uinta Basin in Colorado and Montana found Mountain are notably different from typically standard Plovers selecting nest sites in areas of low shortgrass prairie breeding areas. In Utah veg- herbaceous vegetation and sparse shrub cover etation is sparse; sagebrush communities are 1Department of Zoology, Brigham Young University, Provo, UT 84602. 2Present address: 276 S. 1000 E., Salt Lake City, UT 84102. 3Corresponding author. 229 230 WESTERN NORTH AMERICAN NATURALIST [Volume 61 dominated by Artemisia spp. with a compo- 1500 m to 1920 m elevation. Climate and nent of grasses including Sandberg bluegrass habitats of the Uinta Basin represented within (Poa secunda), Indian ricegrass (Sorghastrum the study area are typical of the shrub-steppe nutans), and needle-and-thread (Stipa comata; habitat type found in the Great Basin (Good- Goodrich and Neese 1986). White-tailed prairie rich and Neese 1986). Vegetative complexes dogs are resident, thinly spread rather than in range from essentially bare sand and/or gravel dense clustered towns, and are known to be to low-growing black sagebrush (A. nova). an ecological “keystone” species in creating Greasewood (Sarcobatus vermiculatus), shad- suitable habitat for other species, including scale (Atriplex confertifolia), and occasional the Mountain Plover (Gilbert 1980, Terborgh big sagebrush (A. tridentata) stands are spo- 1986). Prairie dogs graze on vegetation, and radically present throughout the area. their mounds, being relatively bare, provide open space. Because of their habitat require- METHODS ments, Mountain Plovers are strongly associ- ated with active black-tailed prairie dog towns Mountain Plover surveys have been con- in Montana in their breeding, nesting, and feed- ducted in the study area since 1993 (UDWR ing areas (Knowles et al. 1982, Olson 1985). 1995). Vegetation surveys were completed at Where Mountain Plovers breed in Utah, oil and all known nest sites from 1993 to 1998 (n = gas development contributes to the amount of 11) and at 20 randomly selected sites. Random surface disturbance and bare ground. These points were selected by choosing 20 sections habitat modifications may have some benefits, from the total study area and fixing the sample and Mountain Plovers are known to raise point as close to the center of the section as broods near excessive local disturbance (Knopf possible. At each site we measured a 10-m- and Miller 1994). radius macroplot and sampled ten 1-m2 The diet of the Mountain Plover through- quadrats within the macroplot. We then esti- out its breeding range consists mainly of mated percentage of each of the following: ground-dwelling and winged invertebrates total vegetative cover, shrub, forb, grass, total perched on the ground; foraging is oppor- rock cover, large rock (>7 cm), medium rock tunistic (Knopf 1996). (2–7 cm), and small rock (<2 cm). We also It is of interest that a small Mountain Plover counted the number of species noted as population is able to breed in Utah. There are shrubs, forbs, grasses and grasslikes. Measure- no data to indicate whether the Myton Bench ments were taken of maximum and average population is a relic; thus, it is important to vegetation heights. Presence or absence of know which habitat characteristics the Moun- white-tailed prairie dogs was noted. Distance tain Plover prefers when selecting a nest site from nearest prairie dog mound, roadway, and in this atypical region. Information is also well pad was recorded at each nest site. Slope needed to understand the impacts of intensive and aspect at each nest site were also recorded. oil development and associated vegetative In 1998 potential prey availability was sam- changes on this population. The objectives of pled. We collected insects from nest areas and this study were to quantify habitat parameters random sites before and during Mountain at Mountain Plover nest sites in the Uinta Plover nesting time and then again after hatch- Basin and measure available food resources at ing. Collection areas were approximately cir- these sites. cular, extending about 0.2 km in radius from each nest or at randomly selected points. Forty STUDY AREA minutes was spent at each collection site, and anything visible to the surveyors was caught Surveys were done from Castle Peak and with sweep net or forceps. All insects col- Wells Draws east to the border of Pariette lected were classified to the level of family by Wetlands Wildlife Habitat Management Area, Richard W. Baumann, Monte L. Bean Life approximately 20 km southwest of Myton, Science Museum, Brigham Young University. Duchesne County, Utah. The study area gen- Using discriminant analysis, stepwise dis- erally encompasses T8S to T9S, and R16E to criminant analysis, and Wilcoxon 2-sample R18E. These areas have a highly variable, bro- tests, we compared 14 habitat characteristics ken topography ranging from approximately at nest and random sites. The diversity of 2001] NEST SITE SELECTION BY MOUNTAIN PLOVERS 231 insects collected at nest and random sites was al large visual barriers are not as great a hin- estimated with the Shannon function (Pielou drance to the Mountain Plover in Utah as in 1977) and then compared with Wilcoxon rank other parts of the breeding range. sums tests. A pooled t test for small samples Regardless of degree of slope, the prairie was used to compare Utah nest sites with nest dog plays an important role for Mountain sites in Montana and Wyoming. Plovers as 4 of 5 nest sites in Utah in 1998 were located an average of 8.5 m from a RESULTS AND DISCUSSION white-tailed prairie dog mound (Table 1).