Micro-habitat characteristics of
Mountain plover nest sites
Jody J. Javersak, Sitka, AK 99835
Daniel W. Uresk, USDA Forest Service, Rapid City, SD 57701
Milton Joe Trlica, Department of Forest and Rangeland Stewardship, Colorado State University,
Fort Collins, CO 80523
This study was conducted on shortgrass prairie in northeast Colorado to determine micro-habitat
characteristics of nest sites for mountain plover (Charadrius montanus Townsend). Vegetation
and soil surface characteristics were sampled in the spring of 1996-97 at and near 16 nests to
identify important micro-habitat characteristics for site selection. We collected data on plant
structure and canopy cover near nests in the spring during 2 years. Mean bare ground within a
15 m radius of the nest was 24 percent and bare ground patch size was 29 cm2. Mountain plovers
selected nest sites that had short plant structure and a mean visual obstruction reading (VOR)
of 0.6 cm. Plant structure (VOR) from 4 m to 15 m was significantly greater than structure at
0 to 2 m from the nest.
Key Words: mountain plover, grazing, habitat, plant height, soil surface, visual obstruction.
mountain plover as a threatened species was
withdrawn May 12, 2011. It was determined
The mountain plover (Charardrius
that the mountain plover was not threatened
montanus) is found on level sites with
or endangered throughout all or a significant
sparse, short vegetation throughout most of
portion of its range. Though not listed as
its range (Olson and Edge 1985). Bradbury
an endangered species the, mountain plover
(1918, page 157) described a mountain
should receive continued surveillance just
plover nesting area 20 miles east of Denver
to maintain existing populations. The
as cattle range “…covered with short-
purpose of this study was to determine nest
cropped buffalo or grama grasses with
selectivity of mountain plovers by assessing
frequent bunches of dwarfed prickly pear,
and describing vegetation and soil surface
and an occasional cluster of stunted shrub
characteristics at, and directly surrounding
or weed…”. Graul (1975) found most
mountain plover nests in Colorado.
mountain plover nest sites in Weld County,
Colorado in shortgrass areas of blue grama
(Bouteloua gracilis) and buffalograss
(Buchloe dactyloides) with scattered clumps
The study area was in northeastern
of plains prickly pear (Opuntia polyacantha)
Colorado near Keota in Weld County and
and western wheatgrass (Pascopyrum
within the Pawnee National Grassland.,
smithii). There is little information focusing
The grassland encompasses 78,162 ha of
specifically on the micro-site characteristic
publicly owned tracts of and intermingled
of mountain plover nest sites. The mountain
with privately owned farms and ranches.
plover was originally proposed as threatened
The area is classified as a shortgrass steppe;
or endangered according to the Endangered
blue grama, buffalograss, plains prickly
Species Act of 1973 in 1999 (Federal
pear, western wheatgrass, and sun sedge
Register 2011)in 2002 but was withdrawn
(Carex inops) are the principal plant species
from consideration in 2003. In 2010, the
(USDA NRCS 2004). Other plant species
mountain plover was again proposed as a
present included woolly plantain (Plantago
threatened species. The proposal to list the
patagonica Jacq.), rubber rabbitbrush
(Ericameria nauseosa [Pall. ex Pursh] G.L.
additional sample stations at 2, 4, 6, and 8
Nesom & Baird), sixweeks fescue (Vulpia
m from the nest along the transects in 1997
octoflora), and fourwing saltbush (Atriplex
in an attempt to more precisely describe the
canescens). The soil type in the study area
vegetation zone around the nest.
is an Ascalon-Vona sandy loam, a deep well-
Canopy cover by major plant species, total
drained Ustollic Haplargid (Crabb 1982).
grasses, total forbs, total plants and bare
ground (Daubenmire 1959) and soil surface
characteristics (percent bare ground and bare
Mountain plovers, in a preliminary search of
ground patch size) were estimated within 20
the study area, were most frequently found
x 50 cm quadrats positioned at 1 m intervals
on loamy plains range sites with less than 2
along each of the four 15 m transects. Bare
percent slope and a southern to southwestern
ground patch size within each quadrat was
aspect in the study area. We selected 8
classified into 1 of 6 class codes (Table 1).
sites with these attributes that were 1.6 to
Mid points of class codes were used to
15 kilometers apart and roughly 500 ha in
estimate patch size (cm2) following methods
size to search for plover nests. Searching
described by Daubenmire (1959).
for individual plovers began at sunrise and
continued through sunset during the nesting
Table 1. Class codes (1-6) with
period. Once a plover was located, it was
corresponding size of bare ground patches.
observed until it settled on the nest. The
Mid points of patch size were used to
nest was then located and data collected
estimate area (cm2).
within a very short time. We initially
searched the selected sites for mountain
plover nests in spring, 1996. Because so
few nests were found on the 8 study sites in
the spring of 1996, we expanded the search
0 - 3.2
in 1997 to include larger areas outside the
3.3 - 12.6
original study sites that were potentially
12.7 - 28.3
good mountain plover habitat.
28.4 - 50.3
We measured vegetation height-density
50.4 - 78.6
(density of leaf mass at various heights
determined by visual obstruction readings
on a Robel pole) and cover along 15 m
VOR data at the nest site and along the
transects radiating outward in the 4 cardinal
transects at various distances (meters) were
directions from each nest during the nesting
analyzed with a General Linear Model
period. We recorded the height-density
repeated measures design (SPSS, 2003)
or visual obstruction reading (VOR)
for both years. The Bonferroni pairwise
of vegetation for each nest site using a
comparisons test was used to determine
modified Robel pole as described by Uresk
significance differences between VORs at
and Benzon (2007) and Uresk and Juntti
the nest site and at distances from the nest.
(2008). The modified pole had alternating
We used a two sample T-test to compare
1.27 cm white and gray rings. Bands were
differences between years for canopy cover
numbered beginning with 0 (white band) at
variables and patch size at p = 0.10.
the bottom and the pole was placed on the
soil surface. A (VOR) was taken from a
distance of 4 m from the pole for each of the
Sixteen nests were located during the 2
four cardinal directions. The lowest visible
years of sampling: 6 in 1996 and 10 in 1997.
band was recorded. Visual obstruction
Mean VOR at time of nesting for 6 nest
readings were recorded at the nest site
sites in 1996 was 0.9 cm ± SE 0.3 and for
and at points 10 and 15 m from the nest
10 nest sites in 1997 VOR was 0.3 ± SE 0.2.
along each of the four transects. Because
Bare ground, bare ground patch size, and
1996 data showed significant differences
canopy cover of major plants and categories
between the nest and 10 m station, we added
within the 15 m radius of the nest is shown
Micro-habitat Characteristics of Mountain Plover Nest Sites 27
in Table 2 for both years. Differences (p =
1976; Leachman and Osmundson 1990).
0.10) were observed between years for blue
Micro-site characteristics were important
grama, total cover and total graminoids with
to mountain plovers nesting on the Pawnee
1996 providing greater canopy cover than
National Grassland. With a refinement
in 1997. Overall, bare ground was 24% ±
of the sampling design in 1997, the zone
SE 2%, bare ground patch size 29 cm2 ± SE
of greatest influence was shown to be a
3cm, total plant cover 69% ± SE 3%, total
distance of about 2 m compared to distances
graminoides 67% ± SE 3% and total forbs
from 4 through 15 m from the nest. Once
4% ± SE < 1%.
an area had been selected for a breeding
VOR was greater at stations away from
territory, the vegetation structure, cover,
the nest. For combined years, mean VOR
and amount of bare ground were important
at the nest station (0.06 ± SE 0.2 cm) was
characteristics of the actual nest site location
significantly less than VOR at both 10 m
by mountain plovers.
(1.8 ± 0.3 cm) and 15 m stations (2.0 ± 0.3
Visual obstruction readings at the nest
cm) ) (p = 0.05). In 1997, VOR’s estimated
site were slightly greater (0.57 cm) in our
at 10 nests sites and at 2 m away from
study in Colorado compared to values
the nest were similar (Fig. 1, p > 0.10).
(0.13 cm) reported by Parrish et al. (1993)
However, mean VOR at the 4 m station
in Wyoming. In Colorado on shortgrass
and beyond to the 15 m were similar but
prairie, plover nests were found in blue
significantly greater than at or less than 2 m
grama, buffalograss, and western wheatgrass
of the nest p = 0.10 (Fig. 1).
grazed by cattle. Nesting sites were located
in areas with 24 percent bare ground
distributed in an average patch size of 29
Mountain plovers prefer areas that have
cm2. Olson and Edge (1985) reported 27
been intensively grazed by livestock and
% bare ground (erosion pavement) for nest
avoid areas of vegetation greater than 0.5
sites in Montana. However, Parrish et al.
cm high for nesting (Graul and Webster
(1993) and Plumb et al. (2005) reported
Table 2. Vegetation and soil surface characteristics measured within a 15 m radius of
Mountain Plover nests on the Pawnee National Grassland for years 1996-1997 and years
combined for 16 nest sites.
Mean ± Se
Mean ± Se
Mean ± Se
(n = 6)
(n = 10)
8.0 ± 3.2a
5.7 ± 2.4
6.6 ± 1.9
23.0 ± 7.1 *
41.5 ± 5.9
34.6 ± 5.0
38.3 ± 3.6
22.9 ± 7.9
28.7 ± 5.4
6.5 ± 1.7
8.7 ± 1.9
7.9 ± 1.3
76.8 ± 1.7 *
63.7 ± 3.6
68.6 ± 2.8
76.3 ± 1.6 *
53.1 ± 6.7
67.2 ± 2.8
4.3 ± 1.3
3.8 ± 0.3
4.0 ± 0.5
21.8 ± 2.4
26.0 ± 2.7
24.4 ± 2.0
Bare ground patch size (cm2)
25.7 ± 3.8
30.6 ± 3.9
28.8 ± 2.8
a Standard error
b Two dimensional cover that does not include the sum of individual species.
* Significantly dif erent between years at p = 0.10
28 Javersak et al.
Fig. 1. Visual obstruction readings (VOR) at different distances away from
mountain plover nests (n = 10) in Colorado for 1997. Different letters above the bars
represent differences among the distances (m) at p = 0.10 with standard errors.
nesting at areas of 72% and 47% bare
homogeneous vegetation structure. To
ground, respectively, on grasslands in
create or maintain optimal mountain
plover habitat, grazing intensity should be
Livestock grazing has been used as a tool
heavy during fall, winter and early spring.
for wildlife habitat management (Severson
Livestock grazing provides managers with
1990). Grazing management can be an
some control for creating favored plover
important and perhaps less expensive tool
habitat. Creating vegetation areas with
than mowing or prescribed fire for creating
VORs with a mean of 0.6 + SE 0.2 cm with
or maintaining mountain plover nesting
livestock grazing could provide conditions
habitat. Prairie dog colonies are important
of height-density structure and patchiness
for plover nesting and should receive a high
for attracting plovers.
management priority: however, managing
Mountain plovers use grasslands with low
and maintaining prairie dog colonies is
canopy cover, high percentage of bare
difficult with continued outbreaks of plague
ground and low visual obstruction near
and rodenticide poisoning on the plains
nests. Target conditions for optimal nesting
(Miller et al. 2007). Grazing management
habitat for mountain plovers include less
plans related to the amount of herbage
than 70 percent total vegetation canopy
remaining after livestock grazing are
cover , bare ground of 24 percent or greater
generally designed for optimal livestock
and visual obstruction readings of vegetation
or plant production and often result in
with averages ranging from 0.3 to 0.9 cm.
Micro-habitat Characteristics of Mountain Plover Nest Sites 29
Prairie dog colonies and heavy livestock
Miller, B. J, R. P. Reading, D. E. Biggins,
grazing in late fall, winter or early spring
J. K. Detling, S. C. Forrest, J. L.
provide preferable mountain plover habitat.
Hoogland, J. Javersak, S. D. Miller, J.
These guidelines should be beneficial and
Proctor, J. Truett, and D. W. Uresk. 2007.
effective in keeping the mountain plover
Prairie dogs: an ecological review and
from being proposed as a threatened or
current biopolitics. Journal of Wildlife
Olson, S. L. and W. D. Edge. 1985. Nest
site selection by Mountain Plovers in
We thank Steve Denison, Hank Henry,
north-central Montana. Journal of Range
Lakhdar Benkobi, Mark Ball, and Mary
Ashby for their assistance on this project.
Parrish, T. L., S. H. Anderson, and W. R.
Jeffrey Baumberger assisted with data
Oelkluas. 1993. Mountain Plover habitat
collection. The research was in cooperation
selection in the Powder River Basin,
with Colorado State University Agricultural
Wyoming. Prairie Naturalist 25:219-226.
Experiment Station, Cooperative Agreement
Plumb, R. E., S. H. Anderson, and F. L.
Knopf. 2005. Habitat and nesting
biology of Mountain Plovers in
Wyoming. Western North American
Bradubury, W. C. 1918. Notes on the nesting of
the Mountain Plover. Condor 20:157-163.
Severson, K. E. 1990. Can livestock be used
Crabb, J. A. 1982. Soil Survey of Weld
as a tool to enhance wildlife habitat?
County, Colorado, Northern Part.
43rd Annual meeting of the Society for
USDA, Soil Conservation Service.
Range management, Reno, Nevada,
13 February 1990. K. E. Severson,
Daubenmire, R. 1959. A canopy-coverage
Technical Coordinator. USDA, Forest
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[SPSS] Statistical Procedures for Social
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withdrawal of the proposed rule to list
the mountain plover as threatened;
Uresk, D. W. and T. A. Benzon. 2007.
proposed rule. Part II Department of the
Monitoring with a modified Robel pole
Interior, Fish and Wildlife Service. 50
on meadows in the central Black Hills of
CFR Part 17. Vol 76, No. 92. May 12,
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the Mountain Plover. Wilson Bulletin
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Leachman, B. and B. Oamunsaon 1990.
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literature review. Unpub. Man. Prepared
for the U.S. Fish and Wildlife Serv.,
Golden, Colo. 82 pp.
Received August 2. 2012
Accepted October 25, 2012
30 Javersak et al.