nest habitat selection by rio grande wild turkeys on the edwards

NEST HABITAT
SELECTION BY RIO
GRANDE WILD
TURKEYS ON THE
EDWARDS PLATEAU OF
TEXAS
Justin Z. Dreibelbis1
Kevin L. Skow
Department of Wildlife and Fisheries Sciences,
Texas A&M University,
College Station, Texas 77843, USA
Institute of Renewable Natural Resources,
Texas A&M University,
College Station, Texas 77843, USA
Jason B. Hardin
Markus J. Peterson
Texas Parks and Wildlife Department,
Palestine, Texas 75803, USA
Department of Wildlife and Fisheries Sciences,
Texas A&M University,
College Station, Texas 77843, USA
Nova J. Silvy
Bret A. Collier2
Department of Wildlife and Fisheries Sciences,
Texas A&M University,
College Station, Texas 77843, USA
School of Renewable Natural Resources,
Louisiana State University Agricultural Center,
Baton Rouge, LA 70803, USA
Abstract: Nesting locations selected by wild turkeys (Meleagris gallopavo) have been widely studied, with vegetation
conditions at nest sites regularly identified as important for nest site selection and success. However, nest site selection likely
is also influenced by landscape characteristics. Therefore, we evaluated selection of nest sites by Rio Grande wild turkeys (M.
g. intermedia; hereafter, turkey) at the landscape scale, on sites with and without a fire regime. Across all sites, we found no
apparent differences in estimates of percentage of woodland cover within 100 m of nests for sites that had successful (0.45;
SD = 0.18, n = 26) or failed (0.41; SD = 0.19, n = 130) nesting attempts, nor did we find evidence of differences in edge-toarea ratio between successful (x = 0.22; SD = 0.09, n = 26) or failed (x = 0.21; SD = 0.09, n = 130) nests. Females selected
areas burned the previous year roughly proportional to availability. Across nesting seasons (2005–2007), female turkeys
avoided nesting in dense Ashe juniper–oak (Juniperus ashei–Quercus spp.) woodlands, but instead nested in areas prescribe
burned within the previous 5 and 10 years, which maintained savannah–woodland landscapes. Although only one site was
regularly burned, females on unburned sites selected nesting locations nearly identical in both landscape composition and
edge-to-area ratio to those selected on the burned site. Our study indicates that turkeys consistently selected nesting habitat
with a heterogeneous spatial vegetation structure. Managers should provide vegetation diversity for nesting turkeys such that
a range of nesting habitat conditions is readily available.
Proceedings of the National Wild Turkey Symposium 11:107–116
Key words: disturbance, habitat management, habitat selection, Meleagris gallopavo intermedia, nest success,
reproduction, Rio Grande wild turkey, Texas, vegetation.
Associate Editor: Wakeling
1
Present address: Texas Parks and Wildlife Department, 4200 Smith School Road, Austin, TX 78744, USA.
2
E-mail: [email protected]
107
108
Habitat Use and Movements
Habitat characteristics for nesting and brooding by
wild turkeys (Meleagris gallopavo) have been widely
studied across the United States (e.g., Healy 1985, Schmutz
et al. 1989, Chamberlain and Leopold 2000, Lehman et al.
2002, Randel et al. 2005), with vegetation regularly
identified as the driver of nest-site location for both the
eastern (M. g. silvestris) and Rio Grande (M. g. intermedia)
subspecies (Lazarus and Porter 1985, Porter 1992, Lehman
et al. 2002, Randel et al. 2005). Vegetation characteristics
related to ground cover height (Badyaev 1995, Randel et al.
2005), increased visual obstruction (Badyaev 1995, Keegan
and Crawford 2005, Randel et al. 2005), and vegetation
distribution on the landscape (Donovan et al. 1987, Miller
et al. 1999) have been the most frequently identified drivers
of successful nests. In general, habitat selection is likely a
function of size, shape, distribution, configuration, and
connectedness of different vegetation patches (Wiens et al.
1993), rather than micro-scale (e.g., at the nest) habitat
conditions. Researchers have also identified various
vegetation or anthropomorphic characteristics that influence nest success (Keegan and Crawford 1999, Randel et
al. 2005), but managers cannot readily manage factors such
as screening cover, distance to edge or water, or individual
shrub species availability.
The Edwards Plateau of Texas has supported historically robust Rio Grande wild turkey (hereafter, turkey)
populations (Walker 1954, Beasom and Wilson 1992).
Texas Parks and Wildlife personnel have conducted
surveys since the 1970s (Collier et al. 2007, 2009), and
this, combined with anecdotal information from landowners, demonstrated that turkey abundance has declined
within the southeastern Edwards Plateau (Collier et al.
2007, 2009; Dreibelbis et al. 2008; Melton et al. 2011). One
potential explanation for this trend is poor recruitment,
driven at least in part by nest predation (Randel et al. 2005;
Drebelbis et al. 2008, 2011; Melton et al. 2011).
Historically, oak–juniper (Quercus spp.–Juniperus asheii)
savannahs (Smeins 1980), characterized as wooded grasslands with small, woody patches nested within a grassland
matrix, were maintained with cool season fire intervals of
,25 years (Fuhlendorf et al. 1996). However, fire
suppression and concomitant landscape fragmentation has
resulted in great-density, older-growth Ashe juniper forests
becoming the climax community (Smeins 1980). This
conversion of forest types from grass-dominated, oakwoodland savannah to a juniper-dominated woodland has
potential to negatively influence nest success for turkeys by
reducing area of potential nesting and brooding habitat.
Although repeated disturbance (e.g., intensive annual
grazing) can negatively influence many systems, managed
disturbance regimes can be useful for maintaining habitat
conditions in earlier successional stages preferred by
turkeys in semi-arid regions (Smeins 1980, Porter 1992).
We examined potential impacts of fire on nest site selection
by Rio Grande turkeys to better inform rangeland
management by (1) evaluating nest success and nest site
selection at the landscape scale on a site with a known fire
regime; (2) quantifying spatial structure of disturbed areas
relative to undisturbed areas, and (3) comparing habitat
selection and spatial structure of selected habitat types for
nesting at alternate study locations not under a systematic
fire regime to determine if generalities in selection of
nesting habitat occurred.
STUDY AREA
We conducted our research on the Edwards Plateau of
Texas from January through July of 2005–2007 on study
sites in Kerr, Real, Bandera, and Medina counties. Our 4
primary study sites were underlain with limestone bedrock
(Gould 1975). Grazing and fire suppression had gradually
converted our study regions to brushlands, with woodlands
consisting primarily of live oak (Quercus virginiana)
mottes and Ashe juniper thickets. One study site was the
Kerr Wildlife Management Area (WMA), administered by
Texas Parks and Wildlife Department, with other sites on
privately owned lands. All sites allowed hunting of both
native and exotic wildlife, primarily white-tailed deer
(Odocoileus virginianus), with limited turkey hunting (,2
individuals harvested/yr), and all sites were used actively
for livestock production. The Kerr and Real study sites
were in areas where there was no trend in turkey
abundance over time (hereafter, stable sites), whereas the
Medina and Bandera study sites were in areas where turkey
abundance had declined over the past 30 years (hereafter,
declining sites; Collier et al. 2007, 2009; Melton et al.
2011).
METHODS
We trapped turkeys between January and March,
2005–2007, using drop nets and walk-in traps baited with
milo. We fitted captured individuals with mortalitysensitive, backpack-style radiotransmitters (69.0–95.0 g;
Advanced Telemetry Systems, Isanti, Minnesota, USA).
Animal use and handling was conducted under Texas A&M
University Animal Use Permit 2005-005. We triangulated
female locations 3 times weekly during breeding season
until behavioral shifts indicated that nest incubation had
begun (Collier et al. 2009). We attempted to locate nests
within 1 day after we suspected incubation had initiated to
determine nest location, nest initiation date, and clutch size
(Melton et al. 2011). We estimated nest age and initiation
date by back-dating from the day we found nests to the day
we first located females in nest areas. We monitored each
female on a nest 3 times weekly from a distance of 100 m
to prevent further disturbance. Beginning 1 week before
estimated hatch date, we visited each nest area daily to
ensure accurate identification of hatch date (Melton et al.
2011). We classified nest fates as apparent success (i.e.,
hatching of 1 egg) or failure (via female absence at the
nest 2 days, egg remains or lack thereof, or photographic
evidence of predation or abandonment).
We compiled burn records from Kerr WMA to
identify timing of prescribed fires at the pasture scale
(between 40 and 162 ha). We categorized nest locations
into historically burned and non-burned areas to evaluate
frequency of female use during nesting activities. We used
a fire return interval of both 5 and 10 years as our window
for evaluating selection, as the Edwards Plateau was semiarid with pulses of substantially greater precipitation on a
3- to 5-year cycle (Smeins 1980). We assumed that both 5
Rio Grande Turkey Nesting Habitat Dreibelbis et al.
109
Table 1. Proportion of area on the Kerr Wildlife Management Area (WMA) that was affected by prescribed fire (ha [percentage of area
on Kerr WMA]) in both 5 and 10 years prior to each year of our study and number of Rio Grande turkey nest locations, as determined by
radiotelemetry, by each year that fell within boundaries of burned areas on the Kerr WMA, Texas, 2005–2007.
Burned area (ha [%])
Turkey nests locations (n [%)])
Year
5 yr
10 yr
5 yr
10 yr
2005
2006
2007
1,458 (22.6)
2,735 (42.4)
3,377 (52.3)
4,839 (74.9)
4,913 (76.1)
4,977 (77.1)
8 (38.1)
10 (52.6)
14 (82.4)
20 (95.24)
16 (84.2)
16 (94.1)
and 10 years between burns was appropriate for maintaining grassland-savannah characteristics (Smeins 1980,
Fuhlendorf et al. 1996), based on 40 years of historical
burn records and discussions with Kerr WMA staff.
We imported all nest locations into ArcGIS 10 (ESRI,
Redlands, California, USA). We delineated deciduous
woodland patches using 2008 National Agricultural
Imagery Program (NAIP) imagery that maximized vegetation spectral differences. We conducted a supervised
classification of woodlands across our study regions,
aggregating land cover types into 2 classes (woodland
and grassland; Collier et al. 2012). We used 2 general
vegetation classes for our study as most of this region was
defined as oak–juniper woodland and imagery was not
available at a resolution for individual species identification. For each nest, we used a 100-m buffer and calculated
patch size for each woodland patch, mean edge-to-area
ratio for all patches within the buffer, landscape composition for the buffered area (Magness et al. 2006, Locke et
al. 2013), and classified each nest into a time-since-burn
category for Kerr WMA. We estimated, using GIS,
landscape composition as percentage of woodland (e.g.,
woody brushland) within a 100-m-radius circle surrounding
a nest. We determined this radius captured landscape
variation relevant to nesting turkeys (Collier and Chamberlain 2011). We used mean value for all pixels within
each 100-m buffer as landscape composition estimate for
our analyses. We ignored any potential dependence in
multiple nesting attempts by the same individual as Locke
et al. (2013) found no evidence of differential nesting
habitat selection by females across nesting attempts.
We used descriptive statistics to evaluate relationships
among prescribed fire history, nest location and success or
failure, and habitat conditions around nesting locations on
our study sites. We used logistic regression (Venables and
Ripley 2002) conducted in R (v. 3.1.1; R Development
Team Core 2015) to differentiate between successful and
unsuccessful nests using nest-specific estimates of landscape composition and edge-to-area ratio for each study
site. We did this to determine if generalities in turkey
response to local landscape vegetation structure by nesting
females were apparent within our study region. We used
the z test statistic with an alpha level of 0.05 to evaluate if
our predictor variables had a significant effect on nest
success (hatched versus failure) predictions.
RESULTS
We trapped 142 female turkeys between January and
March, 2005–2007 and, after removing mortalities, indi-
viduals who did not nest, and individuals censored due to
radiotransmitter failure, we radiotracked 93 females during
nesting season, resulting in 156 nesting attempts across our
study sites. Across nesting seasons (2005–2007), females
selectively nested in areas where prescribed burning had
occurred in the previous 5 and 10 years (Table 1). Based on
57 nest locations between 2005 and 2007, only 5 females
(8.7%) nested in areas that had not been burned during the
previous 10 years. Females tended to select areas burned
the previous year roughly in proportion to availability, with
no nests in 2005 located in areas burned during 2004
(0.69% of the total area), 21% of nests in 2006 located in
areas burned in 2005 (20% of the total area), and 12% of
nests in 2007 located in areas burned in 2006 (12% of the
total area).
Areas on Kerr WMA that had undergone prescribed
fire were characteristic of savannah habitat conditions, with
large grassland areas interspersed with small woody
patches (Fig. 1). Across all study sites, turkeys selected
nesting areas with significant vegetation heterogeneity
while avoiding dense, woodland areas (Table 2; Fig. 2).
Nest locations in Kerr and Real (stable sites) had smaller
mean percentage of woodland vegetation (33% and 41%,
respectively) than did nest locations on the Medina and
Bandera (declining sites; 50% and 51%, respectively; Table
2). Mean edge-to-area ratios for nesting locations were less
for stable sites (Kerr WMA = 19%, Real = 17%) than
declining sites (Medina = 21%, Bandera = 27%; Table 2).
The lesser bound on range of percentage of woodland
vegetation was almost 15% greater for nests in the
declining as compared to stable sites, indicating that
selected nesting areas contained more woodland cover
(Table 2). Across all study sites, we found no apparent
differences in proportion of woodlands between site where
nests were successful (0.45, SD = 0.18) and sites where
nests failed (0.41, SD = 0.19). Additionally, we did not find
evidence of differences in edge-to-area ratios between sites
where nests were successful (x = 0.22, SD = 0.09) and
sites where nests failed (x = 0.21, SD = 0.09; Fig. 2).
Based on our logistic regression model predictions (Table
3), our results suggested that increased edge-to-area ratio
was associated with nest success for stable study sites (Real
and Kerr), but not for study sites characterized by declining
turkey abundance (Medina and Bandera; Fig. 3). We did
not find a statistical difference between slopes for stable
and declining sites based on increased woodland vegetation
(landscape composition; Table 3; Fig. 3). During 2005–
2007, 29 nests occurred in areas with woodland vegetation
within the landscape composition .60%, with 19 of those
occurring during 2007 (Fig. 4).
110
Habitat Use and Movements
Figure 1. Aerial image of nest locations (triangles) for Rio Grande wild turkeys in savannahs on the Kerr Wildlife Management Area on
the Edwards Plateau of Texas. Insert shows percentage of woodland cover within 100 m of the nest (landscape composition = 53%;
edge-to-area ratio = 17%) for a single nest.
Rio Grande Turkey Nesting Habitat Dreibelbis et al.
111
Table 2. Landscape habitat metrics for nest locations of Rio Grande turkeys, as determined by radiotelemetry, at each of 4 study sites
in the Edwards Plateau of Texas, 2005–2007. We classified Real and Kerr counties as stable sites and Medina and Bandera counties as
declining sites based on perceived population trends.
Nests
Woodland landscape composition
Edge-to-area ratio
Study Site
n
x̄ (SD)
Range
x̄ (SD)
Range
Real County
Kerr County
Medina County
Bandera County
32
67
28
29
41
34
50
51
9–84
6–84
22–74
25–83
17
19
21
27
4–39
5–54
12–54
11–54
(22)
(16)
(18)
(15)
(7)
(8)
(9)
(12)
Figure 2. Boxplots (medians and range) demonstrating estimated percentage of woodland cover within 100 m of nests and edge-to-area
ratios for each landscape buffer (100 m) across study sites (Failed nests = ‘‘–’’, Successful nests = ‘‘þ’’) on the Edwards Plateau of Texas.
Habitat Use and Movements
112
Table 3. Logistic regression model estimates (beta values),
standard errors (SE), and probability for each study site model
used for predicting expected nest success probability based on
woodland landscape composition (LS) and edge-to-area ratio
(EA) at nest locations of Rio Grande wild turkey, as determined
by radiotelemetry, at each of 4 study sites in the Edwards
Plateau of Texas, 2005–2007.
Model
Estimate (b)
SE
z-value
Probability
–2.48
6.54
5.71
1.83
–0.75
0.58
3.40
2.72
3.22
3.21
–4.27
1.92
2.09
0.05
–0.23
,0.001
0.005
0.006
0.56
0.81
–2.25
2.00
2.29
1.20
–0.57
0.55
1.29
1.43
1.33
1.71
–4.06
1.55
1.59
0.90
–0.33
,0.001
0.12
0.11
0.36
0.73
Model = EA
Intercept
Site = Real
Site = Kerr
Site = Medina
Site = Bandera
Model = LS
Intercept
Site = Real
Site = Kerr
Site = Medina
Site = Bandera
DISCUSSION
Females avoided nesting in dense Ashe juniper–oak
but selected nearly identical nest sites relative to landscape
composition and edge-to-area ratio across all 4 study sites.
Thus, although only the Kerr WMA was regularly disturbed
via prescribed fire, turkeys on undisturbed sites still
selected nesting locations nearly identical to those selected
on the Kerr WMA. We suggest this indicates that turkeys
are selecting nest sites based on landscape characteristics
irrespective of management regimes (see Conley et al.
2015). Similar to Locke et al. (2013), our research indicated
that females consistently selected to nest in areas with a
spatially heterogeneous landscape. We found that failed
nests had percentage of woodland vegetation estimates that
were generally less than successful nests, but we found no
clear pattern for successful or unsuccessful nests based on
this. Although our logistic regression predictions indicated
a generally positive effect of increased woodland vegetation and edge-to-area ratio on nest success at our stable
sites, there was no statistical evidence suggesting differences in predicted nest success between stable and
declining study areas. Based on distribution of nests within
various landscape composition values, we suggest some
Figure 3. Logistic regression predictions of nest success across landscape vegetation metrics for Rio Grande wild turkeys nesting
during 2005–2007 on the Edwards Plateau of Texas. Lines represent predictions for each study site (Real [dashed], Kerr [solid], Medina
[dotted], and Bandera [long-dash]). Landscape composition is percentage woodland within a 100-m buffer of nest sites.
Rio Grande Turkey Nesting Habitat Dreibelbis et al.
113
Figure 4. Frequency histogram of Rio Grande wild turkey nest locations across levels of percentage of woodland cover within 100 m of
the nest (landscape composition) for 2005–2007 on the Edwards Plateau of Texas.
114
Habitat Use and Movements
minimum (approximately 20%) and maximum (approximately 60%) thresholds of woodland vegetation within
habitat interspersion provided optimal nesting habitat
conditions.
Although our results were observational (not experimental), areas selected by turkey for nesting in our study
were identifiable and consistent with those created and
maintained with a regular fire regime (i.e., Kerr WMA;
Hurst 1981, Fuhlendorf et al. 1996, Jones et al. 2005). As
nesting locations occurred in areas with large numbers of
small, irregularly shaped, woodland mottes interspersed
within grasslands, females likely selected areas that
provided suitable nesting cover options and available
grassland cover for foraging and subsequent brood
movements (Randel et al. 2005, Locke et al. 2013). Land
management activities should focus on those that create a
mosaic of habitat conditions (Guthery et al. 2005, Keegan
and Crawford 2005). Given consistency with which turkeys
selected nest sites, vegetation structure of the area
surrounding a nest, similar to the area used by the hen
while incubating (Conley et al. 2015), is likely an important
component of nest site selection.
Because some researchers have concluded that lack of
suitable nesting habitat limits turkey populations in some
areas (e.g., Thogmartin 1999, Melton et al. 2011),
management activities are often suggested that focus on
creating quality nesting habitat for turkeys. The Edwards
Plateau is a semi-arid region, so suitability of nesting
habitat in nearly any location within our study region can
be improved during greater precipitation years and has been
shown to influence both turkey productivity and survival
(Schwertner et al. 2005, Collier et al. 2009). Given that
most female mortality occurs during breeding season
(Collier et al. 2009), habitat management activities that
increase available nesting cover (e.g., useable space;
Guthery et al. 2005) likely provide a buffer for females
that nest during lesser precipitation years (Collier et al.
2009). Managers have the ability to measure, but generally
not manage for, nest-level-specific conditions; they should
instead manage for a mosaic of habitat types (e.g., a
grassland–woodland savannah in this system) that provide a
variety of options for nesting turkeys. Based on our results,
disturbance via fire within the Edwards Plateau can be
useful to create and maintain nesting habitat at the
landscape scale. Cool season fire is one management
practice that provides turkeys with favorable habitat
conditions in our study and has done so historically
(Smeins 1980).
MANAGEMENT IMPLICATIONS
With the current trend of urbanization and land
fragmentation occurring across the Edwards Plateau
(Kreuter et al. 2001), landowners and managers should
understand and implement sound habitat management
practices if maintaining suitable turkey habitat is an
objective. Developing wildlife management cooperatives
can provide turkeys with well-managed habitat conditions
across a variety of property ownership boundaries and at
spatial extents relevant to turkey populations (Wagner and
Kreuter 2010). Additional work at the landscape scale,
wherein land is manipulated using a variety of techniques
including fire, brush sculpting, or managed livestock
grazing, should be evaluated to examine which techniques
create available nesting habitat in a cost-effective manner.
ACKNOWLEDGMENTS
Funding for our research was provided by the Texas
Parks and Wildlife Upland Game Bird Stamp Fund and the
Texas State Chapter of the National Wild Turkey
Federation. We gratefully thank the staff of the Kerr
WMA for logistical support during our research. Additionally, we appreciate property access from a number of
private landowners across the Edwards Plateau involved in
this study.
LITERATURE CITED
Badyaev, A. V. 1995. Nesting habitat and nesting success of Eastern
wild turkeys in the Arkansas Ozark highlands. Condor 97:221–
232.
Beasom, S. L., and D. Wilson. 1992. Rio Grande turkey. Pages 306–
330 in J. G. Dickson, editor. The wild turkey: biology and
management. Stackpole, Mechanicsburg, Pennsylvania, USA.
Chamberlain, M. J., and B. D. Leopold. 2000. Habitat sampling and
selection by female wild turkeys during preincubation. Wilson
Bulletin 112:326–331.
Collier, B. A., and M. J. Chamberlain. 2011. Redirecting research
for wild turkeys using global positioning system transmitters.
Proceedings of the National Wild Turkey Symposium 10:81–
92.
Collier, B. A., J. G. Groce, M. L. Morrison, J. C. Newnam, A. J.
Campommizzi, S. L. Farrell, H. A. Mathewson, R. T.
Snelgrove, R. J. Carroll, and R. N. Wilkins. 2012. Predicting
patch occupancy in fragmented landscapes at the rangewide
scale for endangered species: an example of an American
warbler. Diversity and Distributions 18:158–167.
Collier, B. A., D. A. Jones, J. N. Schaap, C. J. Randel, III, B. J.
Willsey, R. Aguirre, T. W. Schwertner, N. J. Silvy, and M. J.
Peterson. 2007. Survival of Rio Grande wild turkeys on the
Edwards Plateau of Texas. Journal of Wildlife Management
71:82–86.
Collier, B. A., K. B. Melton, J. B. Hardin, N. J. Silvy, and M. J.
Peterson. 2009. Impact of reproductive effort on survival of
Rio Grande wild turkey hens in Texas. Wildlife Biology
15:370–379.
Conley, M. D., J. G. Oetgen, J. Barrow, M. J. Chamberlain, K. L.
Skow, and B. A. Collier. 2015. Habitat selection, incubation,
and incubation recess ranges of nesting female Rio Grande
wild turkeys in Texas. Proceedings of the National Wild
Turkey Symposium 11:117–126.
Donovan, M. L., D. L. Rabe, and C. E. Olson, Jr. 1987. Use of
geographic information systems to develop habitat suitability
models. Wildlife Society Bulletin 15:574–579.
Dreibelbis, J. Z., J. D. Guthrie, R. J. Caveny, J. B. Hardin, N. J.
Silvy, M. J. Peterson, and B. A. Collier. 2011. Predator
community and researcher-induced impacts on nest success of
Rio Grande wild turkeys in Texas. Proceedings of the National
Wild Turkey Symposium 10:235–242.
Dreibelbis, J. Z., K. B. Melton, R. Aguirre, B. A. Collier, T. W.
Schwertner, N. J. Silvy, and M. J. Peterson. 2008. Rio Grande
wild turkey nest predation on the Edwards Plateau of Texas.
Wilson Journal of Ornithology 120:906–910.
Fuhlendorf, S. D., F. E. Smeins, and W. E. Grant. 1996. Simulation
of a fire-sensitive ecological threshold: a case study of Ashe
juniper on the Edwards Plateau of Texas, USA. Ecological
Modeling 90:245–255.
Gould, F. W. 1975. Texas plants: a checklist and ecological
Rio Grande Turkey Nesting Habitat Dreibelbis et al.
115
summary. Texas Agricultural Experiment Station Bulletin,
MP-585/Revised.
Guthery, F. S., A. R. Rybak, W. R. Walsh, S. D. Fulendorf, and T.
L. Hiller. 2005. Quantifying usable space for wildlife with useavailability data. Journal of Wildlife Management 69:655–663.
Healy, W. M. 1985. Turkey poult feeding activity, invertebrate
abundance, and vegetation structure. Journal of Wildlife
Management 49:466–472.
Hurst, G. A. 1981. Effects of prescribed burning on the eastern wild
turkey. Pages 81–88 in G. W. Wood, editor. Prescribed fire and
wildlife in southern forests. Belle W. Baruch Forest Science
Institute of Clemson University, Georgetown, South Carolina,
USA.
Jones, B. C., J. E. Inglis, and G. A. Hurst. 2005. Wild turkey brood
habitat use in relation to prescribed burning and red-cockaded
woodpecker management. Proceedings of the National Wild
Turkey Symposium 9:209–215.
Keegan, T. W., and J. A. Crawford. 2005. Rio Grande wild turkey
nest habitat selection in southwestern Oregon. Proceedings of
the National Wild Turkey Symposium 9:245–252.
Kreuter, U. P., H. G. Harris, M. D. Matlock, and R. E. Lacey. 2001.
Changes in ecosystem service values in the San Antonio area,
Texas. Ecological Economics 39:333–346.
Lazarus, J. E., and W. F. Porter. 1985. Nest habitat selection by wild
turkeys in Minnesota. Proceedings of the National Wild
Turkey Symposium 5:67–82.
Lehman, C. P., L. D. Flake, and D. J. Thompson. 2002. Comparison
of microhabitat conditions at nest sites between eastern
(Meleagris gallopavo silvestris) and Rio Grande wild turkeys
(M. g. intermedia) in northeastern South Dakota. American
Midland Naturalist 149:192–200.
Locke, S. L., J. B. Hardin, K. L. Skow, M. J. Peterson, N. J. Silvy,
and B. A. Collier. 2013. Nest site fidelity and dispersal of Rio
Grande wild turkey hens in Texas. Journal of Wildlife
Management 77:207–211.
Magness, D. R., R. N. Wilkins, and S. J. Hejl. 2006. Quantitative
relationships among golden-cheeked warbler occurrence and
landscape size, composition, and structure. Wildlife Society
Bulletin 34:473–479.
Melton, K. B., J. Z. Dreibelbis, R. Aguirre, J. B. Hardin, N. J. Silvy,
M. J. Peterson, and B. A. Collier. 2011. Reproductive
parameters of Rio Grande wild turkeys on the Edwards
Plateau, Texas. Proceedings of the National Wild Turkey
Symposium 10:227–233.
Miller, D. A., G. A. Hurst, and B. D. Leopold. 1999. Habitat use of
eastern wild turkeys in central Mississippi. Journal of Wildlife
Management 63:210–222.
Porter, W. F. 1992. Habitat requirements. Pages 203–213 in J. G.
Dickson, editor. The wild turkey: biology and management.
Stackpole, Mechanicsburg, Pennsylvania, USA.
R Development Core Team (2015). R: A language and environment
for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0 , http://www.
R-project.org/.. Access 5 May 2015.
Randel, C. J., III, D. A. Jones, B. J. Willsey, R. B. Aguirre, J. N.
Schaap, M. J. Peterson, and N. J. Silvy. 2005. Nesting ecology
of Rio Grande wild turkeys in the Edwards Plateau of Texas.
Proceedings of the National Wild Turkey Symposium 9:212–
218.
Schmutz, J. A., C. E. Braun, and W. F. Andelt. 1989. Nest habitat
use of Rio Grande wild turkeys. Wilson Bulletin 101:591–598.
Schwertner, T. W., M. J. Peterson, and N. J. Silvy. 2005. Effect of
precipitation on Rio Grande wild turkey poult production in
Texas. Proceedings of the National Wild Turkey Symposium
9:127–132.
Smeins, F. E. 1980. Natural role of fire on the Edwards Plateau.
Pages 4–16 in L. D. White, editor. Prescribed burning of the
Edwards Plateau. Texas Agricultural Extension Service.
Thogmartin, W. E. 1999. Landscape attributes and nest-site
selection in wild turkeys. Auk 116:912–923.
Venables, W. N., and B. D. Ripley. 2002. Modern applied statistics
with S. Fourth Edition, Springer-Verlag, New York, New
York, USA.
Wagner, M. W., and U. P. Kreuter. 2010. Groundwater supply in
Texas: private land considerations in a rule-of-capture state.
Society and Natural Resources 17:349–357.
Walker, E. A. 1954. Distribution and management of the wild
turkey in Texas. Texas Game and Fish 12:12–14, 22, 26–27.
Wiens, J. A., N. C. Stenseth, B. Van Horne, and R. A. Ims. 1993.
Ecological mechanisms and landscape ecology. Oikos 66:369–
380.
Justin Z. Dreibelbis is the Private Lands and Public Hunting
Program Director for Texas Parks and Wildlife Department. He
received his B.S. and M.S. from Texas A&M University. Justin is an
avid hunter and angler.
Markus J. Peterson is a Professor of Wildlife Ecology and
Conservation at Texas A&M University. He studies wildlife
ecology, conservation, and environmental policy by focusing his
research on processes influencing wild animal abundance, such as
parasitism and disease, predation, weather, habitat conditions, and
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human exploitation, and processes influencing environmental policy
formation and implementation, such as environmental democracy,
public processes used in environmental decision making, and how
the legal and economic social systems influence environmental
decision making. Markus received his Ph.D. and M.S. degrees in
Wildlife Ecology and Conservation from Texas A&M University,
his D.V.M. from Washington State University, and his B.S. from the
University of Idaho.
Kevin L. Skow is the Geospatial Technology Laboratory Manager
for the Texas A&M University Institute of Renewable Natural
Resources (IRNR) in College Station, Texas. Kevin serves as the
GIS lead for all projects at IRNR, including GIS analysis, data
management and supporting web-based mapping applications
focused on natural resource issues. He graduated with a bachelor’s
degree in Rangeland Ecology and Management from Texas A&M
and worked as a GIS specialist for the USDA Farm Service Agency,
before joining the lab at Texas A&M IRNR. Kevin is an avid hunter
who loves wildlife and the land they inhabit, making GIS and
wildlife research a natural fit.
Nova J. Silvy is a Regents Professor, Senior Faculty Fellow, and
Associate Department Head for Undergraduate Programs with the
Department of Wildlife and Fisheries Sciences at Texas A&M
University. He received his B.S. and M.S. from Kansas State
University and his Ph.D. from Southern Illinois UniversityCarbondale. Nova served as President of The Wildlife Society,
2000–2001 and received the Aldo Leopold Award in 2003. During
his career at TAMU, Nova has received 68 honors and awards,
including being listed as Who’s Who in the World. His research
focus is upland game ecology and, in 2005, his work with prairie
grouse earned him the Hamerstrom Award presented by the Prairie
Grouse Technical Council. He has written over 272 scientific
publications, received over $13 million in grants, and has served as
chair for 105 completed graduate students.
Jason B. Hardin is an Upland Game Bird Specialist with Texas
Parks and Wildlife Department. He received his B.S. from the
Arthur Temple College of Forestry at Stephen F. Austin State
University and his M.S. from Caesar Kleberg Wildlife Research
Institute at Texas A&M University-Kingsville. Jason’s primary
responsibility with Texas Parks and Wildlife is managing the
statewide wild turkey program. Jason is a father of 2, a hunter, and a
landowner.
Bret A. Collier is an Assistant Professor in the School of Renewable
Natural Resources at Louisiana State University. Bret’s research
focus is wildlife population dynamics and development of statistical
methods for wildlife biologists, although he has been known to
delve into a variety of wildlife-related topics. He has been actively
conducting research on wild turkeys, demography and spatial
ecology for the past 12 years. Bret and his wife, Reagan, have a
daughter, Kennedy, and he is both a hunter and landowner.