Prairie Grouse

Abstract

Prairie grouse, which include greater prairie-chicken (Tympanuchus cupido), lesser prairie-chicken (T. pallidicinctus), and sharp-tailed grouse (T. phasianellus), are species of high conservation concern and have been identified as potential indicator species for various rangeland ecosystems. Greater prairie-chickens are found in scattered populations in isolated tallgrass prairie throughout the Midwest, but primarily occur in the more expansive tallgrass and mixed-grass prairies in the Great Plains. Lesser prairie-chickens occur in mixed-grass, shortgrass, and arid shrublands of the southern Great Plains. Sharp-tailed grouse occur in mixed-grass, shortgrass, shrub steppe, and prairie parkland vegetation types and are broadly distributed across the northern Great Plains, portions of the Great Basin, and boreal parkland areas of Alaska and Canada. Due to reliance on a variety of rangeland types, consideration of management and anthropogenic activities on rangelands are critical for prairie grouse conservation. Grazing is one of the more prominent activities that has the potential to affect prairie grouse by altering plant structure and composition, and recent research has attempted to identify the mechanisms of grazing effects on prairie grouse. Fire is another important disturbance affecting grouse habitat, especially considering how the current distribution and intensity of fire differs from what occurred historically. Additionally, human infrastructure in the form of roads and energy development, as well as land conversion and degradation such as tillage and tree encroachment can fragment and reduce habitat for prairie grouse. Finally, weather including drought, extended rain, and temperature extremes are common across the distribution of prairie grouse. Although not directly under management control, the effects of weather are an overarching factor that need to be considered in conservation planning. This chapter will summarize the life-histories and habitat requirements of prairie grouse, discuss how rangeland management and other human activities affect them, highlight major threats to prairie grouse and provide recommendations for future management and research.

1 General Life History and Population Dynamics

Prairie grouse collectively refer to three species of grouse in the genus Tympanuchus: greater prairie-chicken (T. cupido), lesser prairie-chicken (T. pallidicinctus), and sharp-tailed grouse (T. phasianellus; Fig. 9.1), classified within the order Galliformes, family Phasianidae, and sub-family Tetraoninae. Where generalities exist across all three species, we will refer to them collectively as prairie grouse, whereas the specific species is referenced when reviewing information appropriate only for that species. Generally, prairie grouse have relatively fast life-histories with high reproductive effort and short lifespans (typically < 3 years). Home range sizes are variable but can be large (> 2500 ha) relative to other galliforms (Patten et al. 2011; Robinson et al. 2018). While prairie grouse often stay relatively close to established leks (see Sect. 9.1.1), they can disperse great distances to find habitat (Earl et al. 2016). Their populations can fluctuate dramatically between years due to weather, but overall trends are influenced by longer term changes in vegetation conditions. The life cycle of prairie grouse is typically partitioned into broad seasonal delineations of lekking, nesting, brood-rearing, and non-breeding seasons.

Fig. 9.1

Distribution of three species of prairie grouse in North America. Sharp-tailed grouse (a), greater prairie-chickens (b), and lesser prairie-chickens (c) occupy grasslands and shrublands from Texas to Alaska. Most populations occur on rangelands managed for livestock production. Map credit M. Solomon; Photo credits M. Milligan and N. Richter

1.1 Lekking

Prairie grouse are polygynous and have a lek-mating system in which courtship and mating is generally limited to lek sites known as ‘booming’ (greater prairie-chicken), ‘gobbling’ (lesser prairie-chicken), and ‘dancing’ (sharp-tailed grouse) grounds during the spring breeding period (March–May), although males often display at leks in the fall as well (Emlen and Oring 1977). This mating system has multiple potential benefits for females. Lekking is associated with strong female mate choice allowing females to efficiently choose from multiple potential mates. Secondary sexual characteristics, including brightly colored air sacs and eye combs (all species) and elongated pinnae (in both prairie-chicken species) are used by females to identify desirable mates (Robel 1966; Bergerud et al. 1988). Additionally, vocalizations and vigor of display are used as cues of general fitness by females with males in the center of the lek typically doing most of the breeding (Behney et al. 2012). Male prairie grouse provide no parental investment after mating and are closely associated with leks throughout much of the year (Schroeder and White 1993).

Lek locations are generally considered to be stable from year to year, and there is evidence that females prefer to visit established leks over newly formed leks (Schroeder and Braun 1992; Haukos and Smith 1999). However, lek locations can move in response to vegetation conditions when disturbance patterns are dynamic (Hovick et al. 2015a). Females may visit more than one lek, and clusters of leks are important for sustaining populations (Schroeder 1991; Hagen et al. 2017). Often lek locations are used for prioritizing conservation actions because they are conspicuous on the landscape (easily mapped) and most annual prairie grouse activity (e.g., nesting and brood-rearing) occurs within 5 km of a lek (Schroeder 1991; Boisvert et al. 2005; Winder et al. 2015).

1.2 Nesting

Prairie grouse have high reproductive potential with high nest initiation rates, large clutch sizes and high egg viability (Connelly et al. 1998; McNew et al. 2011a). As a result, nest success has consistently been identified as one of the most important vital rates affecting prairie grouse populations (Wisdom and Mills 1997; Hagen et al. 2009; Gillette 2014). Most females, regardless of age, will initiate at least one nest per year. Clutch sizes average 10–12 eggs but can be highly variable across climatic gradients (McNew et al. 2017). Additionally, clutch size can be smaller for greater prairie-chickens during early and warm springs suggesting that external environmental cues may be related to nest initiation (Londe et al. 2021b). If the initial clutch is lost during laying or early in incubation, females will often renest, and clutch sizes of renests are typically smaller than initial nests (Hagen and Giesen 2005; Johnson et al. 2020). The probability of renesting declines as the nesting season progresses (Pitman et al. 2006a; McNew et al. 2011a). The incubation period for prairie grouse averages 25–28 d (Hagen and Giesen 2005; Johnson et al. 2020). Generally, the peak of hatching occurs during May–June; local environmental conditions can impact average incubation and hatch dates of nests (McNew et al. 2011b; Londe et al. 2021b).

Nest success, the proportion of nests that hatch ≥ 1 egg, varies across years and sites for a variety of reasons, including differences in weather, age structure of the population, predator populations, and differences in local and landscape habitat conditions. Weather has been found to strongly influence nest fate for greater prairie-chickens in the southern Great Plains (Hovick et al. 2015b; Londe et al. 2021b) and sharp-tailed grouse in the northern Great Plains (Milligan et al. 2020a). Nest success can also vary between first nests and renest attempts (Hovick et al. 2014a, b; Williamson 2009) in relation to seasonal variation in nesting habitat conditions (McNew et al. 2011a). Additionally, higher nest success for adults (≥ 2nd breeding season) than yearlings (1st breeding season) has been reported (Bergerud et al. 1988), although others have observed no difference in nest success between adult and yearling prairie grouse (Apa 1998; Collins 2004; Milligan et al. 2020a; Londe et al. 2021b). Egg viability, or the proportion of eggs that hatch within successful nests, is typically high with at least 90% of eggs hatching (Meints 1991; Pitman et al. 2006b; McNew et al. 2011b).

1.3 Brood-Rearing

Female prairie grouse rear one brood (a group of chicks) per year. Chicks are precocial and follow the female away from the nest shortly after hatching. Chicks cannot thermoregulate for up to two weeks after hatching (Bergerud et al. 1988), making them vulnerable to environmental conditions and dependent on the female to provide temperature regulation from both hot and cold conditions. Broods remain with the female and often stay relatively close to the nesting area throughout the summer (Marks and Marks 1988; Gratson 1988; Meints 1991). Daily summer movements have ranged from 45–276 m (Hart et al. 1950; Pitman et al. 2006a, b).

1.4 Chick Survival

Chick survival is a key determinant of population dynamics and may be an even more limiting factor than nest success for some populations (Hagen et al. 2009). As in most galliforms, the highest period of chick mortality is during the first 2 weeks after hatch, largely due to the inability of chicks to fly or thermoregulate (Bergerud et al. 1988). Survival probability of chicks increases rapidly after this period as they become less dependent on the female for thermoregulation and can escape predators more effectively. As a result, chicks are vulnerable to three main sources of mortality: predation, starvation, and exposure. Reported survival rates of chicks to 35 days of age range from 0.13 to 0.67 (reviewed in Hagen and Giesen 2005; Milligan et al. 2018; Johnson et al. 2020) and likely vary due to local habitat conditions and weather. Estimates of juvenile survival from 35-d to 1-y of age are generally lacking due to the difficulty in capturing and monitoring juvenile prairie grouse and is a research need.

1.5 Non-breeding

The non-breeding season, delineated generally as the period August–February, is the least understood portion of prairie grouse life history. Like other galliforms, research has been focused on the reproductive period, due to both perceived importance of reproductive success to annual recruitment and availability of field researchers during summer months. Survival is generally higher for female prairie grouse during the non-breeding season as compared to the breeding season (Winder et al. 2014a; Robinson et al. 2018; Milligan et al. 2020b). Habitat requirements can be dramatically different during the non-breeding season with grouse selecting different vegetation types (Pirius et al. 2013; Hiller et al. 2019; Londe et al. 2019) and exhibiting contrasting behavioral avoidance of some anthropogenic structures as compared to the breeding season (Londe et al. 2019; Sect. 9.4). During the non-breeding season, prairie grouse may flock to feed on crops, sometimes traveling great distances between grassland cover and crop fields, but the effects of movement, concentration of birds, and use of crops on vital rates is poorly understood (Robinson et al. 2018).

1.6 Survival

Typically, annual survival rates reported for adult prairie grouse have ranged from 0.17–0.43 (McNew et al. 2017) but was observed to be as high as 0.71 in South Dakota for greater prairie-chickens (Robel et al. 1972). Reported differences in survival between adults and yearlings or between sexes are variable with some studies showing no differences (Boisvert 2002; Winder et al. 2018; Milligan et al. 2020b) and others reporting significant differences (Hagen et al. 2005, lesser prairie-chicken; Matthews et al. 2016, translocated sharp-tailed grouse). Increased female mortality is more likely to occur during the nesting season and brood-rearing season (Hagen et al. 2007a; Winder et al. 2014a, 2018; Milligan et al. 2020b), and male mortality typically increases during the lekking period (Collins 2004). Winter mortality depends on the severity of the winter. In Idaho, sharp-tailed grouse survival rates ranged from 0.29 in a severe winter to 0.86 in a mild winter (Ulliman 1995). In southern populations, prairie-chickens generally have high overwinter survival (McNew et al. 2012b; Pirius et al. 2013). Causes of adult mortality include predation (Hagen et al. 2007a; Winder et al. 2018; Milligan et al. 2020b) and collisions with powerlines, fences, and vehicles (Wolfe et al. 2007; Robinson et al. 2018). Maximum reported lifespan of sharp-tailed grouse was 7.5 years, although life-expectancy is < 3 years on average (Connelly et al. 1998). Although estimates for juvenile (i.e., stage from fledging to first breeding season) overwinter mortality for greater prairie-chickens or sharp-tailed grouse are lacking, juvenile survival of lesser prairie-chickens has been reported (0.70; Pitman et al. 2006a). Further work is needed to understand survival of juvenile prairie grouse.

1.7 Seasonal Movements and Dispersal

Prairie grouse are generally considered non-migratory, and seasonal shifts between summer and fall home ranges are often small (< 10 km; Johnson et al. 2020; Stinson and Schroeder 2012). However, longer seasonal shifts up to 50 km have been reported for lesser prairie-chickens (Earl et al. 2016). On average, female prairie grouse move < 2 km from their lek of capture to nesting sites (Schroeder 1991). Movements from nesting to brood-rearing areas are generally short (< 2 km) as well (Collins 2004; Hoffman et al. 2015). However, some females moved more than 3.5 km to brood-rearing sites, potentially due to drought conditions and lack of resources (Collins 2004). Little is known about natal dispersal in prairie grouse because studies of radio-marked juvenile grouse are lacking. Females appear to be the primary dispersers and males remain more localized and perhaps recruit to leks near natal areas (Pitman et al. 2006a; Earl et al. 2016).

1.8 Population Dynamics

Like other game birds, prairie grouse have population cycles that are linked to habitat quality and weather. Interannual variability in habitat quality can be driven by weather (Londe et al. 2021b), especially precipitation (Ross et al. 2016; Fritts et al. 2018) as well as rangeland management. However, these relationships are constrained by landscape-level factors such as patch size, habitat fragmentation, or habitat composition (Hagen et al. 2020). Historically, prairie grouse exhibited cyclical “boom or bust” patterns that were largely dependent upon precipitation or drought conditions. Given the short life span and high reproductive output of prairie grouse, populations can fluctuate from year to year. This, combined with lack of precision in population size estimates, makes management decisions based on short term (year to year) changes in population indices less reliable and emphasizes the need to evaluate longer term trajectories. Although prairie grouse have likely always fluctuated dramatically as environmental conditions varied, these cyclical patterns have been exacerbated as available habitat was diminished and carrying capacity reduced. Recent evidence indicates that extreme drought coupled with less available habitat leads to slower population recovery and perhaps an inability to rebound to previous abundance levels (Ross et al. 2016; Fritts et al. 2018).

Due to high reproductive effort, reproductive success has a disproportionately large influence on overall population dynamics. Sensitivity analyses of stable populations of lesser prairie-chickens and sharp-tailed grouse show that changes in nest and brood survival have the largest contributions to population dynamics (Hagen et al. 2009; Gillette 2014). However, the relative importance of adult survival and fecundity varied among populations of greater prairie-chickens, suggesting that human land use patterns can affect the comparative influence among vital rates on population dynamics (McNew et al. 2012b; Sullins et al. 2018). Nevertheless, management prescriptions that improve reproductive success and recruitment are more likely to effectively recover prairie grouse populations than those directed at adult survival (McNew et al. 2012b; Milligan et al. 2018).

2 Current Species and Population Status

2.1 Greater Prairie-Chickens

Three subspecies of greater prairie-chickens historically occurred in North America (Johnson et al. 2020). The extinct heath hen (T. c. cupido) once occupied areas of New England in grasslands and shrublands maintained by frequent fire. The Attwatter’s prairie-chicken (T. c. attwatteri) is currently on the brink of extinction and is maintained in two isolated locations in Texas via captive breeding (Silvy et al. 1999). Only about 1% of the coastal grasslands in Texas that once supported Attwatter’s prairie-chicken remains (Smeins et al. 1991), providing limited carrying capacity. The greater prairie-chicken (T. c. pinnatus) has also shown significant population declines in the last several decades across its continually shrinking distribution (Braun et al.1994; Johnson et al. 2020). Greater prairie-chicken populations, which were once known to occur in 20 states and 4 provinces, are listed as threatened or extirpated in at least 15 states and provinces (Braun et al. 1994; Svedarsky et al. 2000). The earliest documentation by Euro-American settlers indicates that greater prairie-chickens were primarily found in the Midwestern portions of the United States. Some anecdotal notes suggest that grain crops initially caused distribution expansions west and north of historical distribution within the Great Plains (Johnson and Joseph 1989) and Johnsgard and Wood (1968) document that, except for the Flint Hills of Kansas and southeastern Nebraska, most large contemporary populations of greater prairie-chickens occur in areas that were not known to be occupied by this species until after Euro-American settlement.

2.2 Lesser Prairie-Chickens

Lesser prairie-chickens have experienced significant declines in distribution and population size since Euro-American settlement. Historically, the estimated distribution of lesser prairie-chickens extended over 180,000 km² across western Kansas and Oklahoma, eastern Colorado and New Mexico, and north-central Texas. Lesser prairie-chicken populations now occupy 17% of their historical distribution (Garton et al. 2016; Fig. 9.1). Sympatric overlap and hybridization with greater prairie-chickens north of the Arkansas River in northwestern Kansas (Bain and Farley 2002) is likely due to the conversion of former cropland to mixed grass prairie through programs such as the Conservation Reserve Program (Dahlgren et al. 2016); although genetic evidence suggests multiple periods of sympatry during the evolutionary history of these species (DeYoung and Williford 2016). Recent comprehensive population analyses have demonstrated long-term declines during the last century until apparent population stabilization in the mid-1990s (Garton et al. 2016). Regional populations exhibited signs of recovery during the early 2000s, but a range-wide drought during 2011–2013 reduced populations by 50% (McDonald et al. 2014). As a result of this rapid decline and ongoing threats, in 2014, the U.S. Fish and Wildlife Service (USFWS) listed the lesser prairie-chicken as threatened under the Endangered Species Act (1973; ESA). However, the listing was vacated by the U.S. District Court for the Western District of Texas in 2015 due to “substantial efforts already being made by state wildlife agencies, industries, and private landowners to restore and conserve lesser prairie-chicken habitat” (USFWS 2016). Annual population surveys up to 2020 indicated that the species has nearly recovered to 2011 pre-drought abundance levels (Nasman et al. 2020). Nevertheless, in November 2022, the USFWS relisted the lesser prairie-chicken under the ESA, this time into two Distinct Population Segments (DPS); the Southern DPS of lesser prairie-chickens occurring in New Mexico and Texas was listed as endangered and the Northern DPS occuring in Colorado, Kansas, and Oklahoma was listed as threatened.

2.3 Sharp-Tailed Grouse

Sharp-tailed grouse are the most widespread of the prairie grouse (Schroeder et al. 2004; Fig. 9.1), historically distributed across 21 states and 8 Canadian provinces (Aldrich 1963; Johnsgard 1973). There are six subspecies of sharp-tailed grouse, two of which are native to rangelands of western North America; Columbian sharp-tailed grouse (T. p. columbianus) and plains sharp-tailed grouse (T. p. jamesi; Connelly et al. 1998). Originally, the two subspecies were thought to be separated by the Continental Divide, with T. p. jamesii distribution limited to grasslands east of the Rocky Mountains. However, recent genetic evidence suggests that plains sharp-tailed grouse occupied intermountain valleys west of the Continental Divide (Warheit and Dean 2009). A third subspecies, prairie sharp-tailed grouse (T. p. campestris), occurs in rangeland and parkland of the upper Midwestern U.S. and Canada (Johnsgard 2016). The three northern races of sharp-tailed grouse (T. p. caurus, T. p. kennicotti, and T. p. phasianellus) occur in forest-dominated landscapes where information on rangeland management is lacking and are not covered here.

Distribution-wide, sharp-tailed grouse are currently considered stable (BirdLife International 2012; Panjabi et al. 2012). However, populations are extirpated from Kansas, Illinois, California, Oklahoma, Iowa, Nevada, New Mexico and Oregon (Johnsgard 1973). Declines are mainly attributed to habitat loss and fragmentation associated with conversions of rangeland to cultivation and other human development (Connelly et al. 1998; Schroeder et al. 2004). Columbian sharp-tailed grouse occur in remnant populations in British Columbia, Colorado, Idaho, Utah, Washington, and Wyoming (Johnsgard 2016). Columbian sharp-tailed grouse have been petitioned twice for threatened or endangered species listing, however, both instances resulted in a ‘not warranted for listing’ determination (U.S. Fish and Wildlife Service 2000, 2006). The species is listed as threatened by the State of Washington (Stinson and Schroeder 2012), a species of concern by the Province of British Columbia (Leupin and Chutter 2007) and by USFWS, and as a sensitive species by the Bureau of Land Management (BLM) and United States Forest Service (USFS).

3 Population Monitoring

Monitoring efforts for prairie grouse vary considerably and have generally been the responsibility of state and provincial wildlife agencies. In general, Great Plains and Midwestern states allocate twice as much effort monitoring game birds, including prairie grouse, as western states (Sands and Pope 2010). Similarly, there is variation among states relative to data collection on spatial–temporal population fluctuations.

3.1 Lek Surveys

Prairie grouse populations are typically monitored using lek surveys either at established leks or along survey routes (e.g., Utah Department of Natural Resources 2002; South Dakota Game, Fish, and Parks 2010). Spring lek count surveys provide estimates of relative abundance (Cannon and Knopf 1981; Reese and Bowyer 2007; Garton et al. 2016; Hoffman et al. 2015). Long term monitoring must have established protocols and consistent survey effort each year, otherwise comparisons across years are inappropriate (Luukkonen et al. 2009; Hoffman et al. 2015). Generally, population estimates are calculated by doubling the maximum count of males on leks in spring; this method assumes that all males attend leks and the sex ratio is at parity (Schroeder et al. 2008).

Recent work has highlighted several potential biases associated with using unadjusted counts of birds (e.g., lek counts) that are observed imperfectly (Royle and Dorazio 2008; Walsh et al. 2004). Certainly, raw lek counts should not be used to describe true population sizes or evaluate short-term population dynamics. Evaluations of scale-associated biases of lek counts as population indices are lacking for prairie grouse. However, recent work evaluating biases associated with lek survey protocols for sage-grouse indicate that lek count data generally correlate with annual abundance of males (Fedy and Doherty 2011), especially when (1) leks are surveyed multiple times each spring and the maximum or peak count is used as the index, and (2) inferences about trends are evaluated at large spatial scales (e.g., ≥ 50 leks; Fedy and Aldridge 2011). However, single counts timed to match the peak of attendance at more leks appear to have greater use than multiple counts at a smaller number of leks when the objective is monitoring at the scale of a population (e.g., hunting district; Fedy and Aldridge 2011). Research aimed at understanding covariate effects (e.g., habitat management) on population trends at local spatial scales, however, should strive to separate observation error (e.g., imperfect detection) from process variance (e.g., population size or growth rates) (Dail and Madsen 2011; Blomberg and Hagen 2020).

Recently, distribution-wide population monitoring for lesser prairie-chickens began aerial surveys to estimate annual abundance (McDonald et al. 2014). A probabilistic spatially balanced sampling frame composed of 15 × 15 km grid cells is laid over the regional distributions of the species. Grid cells are randomly selected for aerial surveys within each season. Two helicopter transects are flown per grid cell per year and all birds observed along each transect are counted by two observers, one located in the front and one in the rear of the helicopter. This double-observer method enables rigorous estimates of detection probability and abundance. Additionally, this grid has been adapted to estimate spatio-temporal changes in prairie-chicken occupancy as a function of landscape, habitat, and climatic covariates (Hagen et al. 2020).

3.2 Harvest Surveys

Surveys of grouse hunters by mail, phone, or at check stations are used by several states to index or estimate harvest (Sands and Pope 2010). Hunter reported harvests are used by management agencies to estimate harvest rates, estimate hunter effort, and index annual population sizes (e.g., South Dakota Fish, Game, and Parks 2010). Hunter-reported harvests should be considered an index of harvest, rather than true harvest, as respondents may inflate the number of birds they harvest (Atwood 1956; Martinson and Whitesell 1964). Generally, the total number of birds harvested, even if indexed accurately, is related more to hunter effort (number of hunters and days afield) than it is to population size. Thus, reported harvest rates are sometimes divided by reported hunter effort (e.g., harvest per hunter days) and this ratio used to index annual population sizes and temporal population trend (Beaman et al. 2005). This approach assumes that biases in reported hunter effort (rounding of effort, typically up) are consistent over time and across management units. Another major source of potential error associated with harvest surveys of hunters is non-response bias. Unsuccessful hunters who tend to not respond to surveys can have major influences on estimated harvest rates; however intensive resampling of non-respondents by mail and phone can minimize bias or allow surveyors to calculate correction factors (Aubry and Guillemain 2019). Harvest information provided by hunters at mandatory check stations are considered more reliable (Dahlgren et al. 2021).

3.3 Wing and Feather Collections

Several wildlife agencies use wing, tail, and scalp feather collections from harvested birds to provide information on sex and age-composition of the population, either through volunteer collection containers (“wing barrels”) at common bird-hunting areas (Hoffman 1981) or from targeted mail-in programs (e.g., Alaska Department of Fish and Game; Idaho Department of Fish and Game). The collection of wings and tails from hunter-harvested birds is inexpensive relative to other monitoring programs that require active brood surveys or intensive telemetry-based studies. However, harvest metrics garnered from age- or sex-ratios estimated from hunter-harvested wings and tails likely do not accurately reflect population processes of interest (e.g., productivity, recruitment) because of differences in harvest vulnerability among sex and age-classes (Pollock et al. 1989). Empirical assessment of these biases for prairie grouse are lacking but have been demonstrated for other species of upland game birds [ruffed grouse (Bonasa umbellus): Fischer and Keith 1974; northern bobwhite (Colinus virginianus): Roseberry and Klimstra 1992; sage-grouse: Hagen et al. 2018]. Harvest rates of juveniles are generally higher than adults; therefore, age-ratios (juvenile:adult females) from harvested birds will yield upward biased estimates of true productivity and result in incorrect inferences regarding population dynamics, habitat quality, and other ecological processes of interest. Age-ratios from hunter-harvested wings may provide relative estimates of productivity across management units and years if harvest effort and harvest vulnerability of both juveniles and adults are consistent across space and time. This seems unlikely given annual variability in hunter effort (e.g., 5–30% annually; Oregon Department of Fish and Wildlife 2020), variability in harvest vulnerability (Caudill et al. 2017), and habitat/location effects on harvest rates (e.g., Breisjøberget et al. 2018; Davis et al. 2018). Further convoluting the use of hunter-collected materials is that biases due to vulnerability may or may not change during a single season (Flanders-Wanner et al. 2004). Overall, the use of uncorrected age- and sex-ratios from hunter-harvested wings and tails is tenuous. At a minimum, assessments of bias due to systematic changes in harvest-age ratios is a prerequisite of population-level analyses (Flanders-Wanner et al. 2010; Hagen et al. 2018). Information provided by hunter-harvested wings and tails are better used to monitor the distribution and timing of harvest, rather than the sex- or age-structure of the population.

3.4 Combining Multiple Datasets

Wildlife agencies often collect multiple independent datasets (e.g., lek counts, hunter surveys, wing/tail collections, habitat indices) (Broms et al. 2010). In some cases, a formal decision-making system like adaptive harvest management is used (Dahlgren et al. 2021). Integrated population models (IPMs; Schaub and Abadi 2011) were developed specifically to (1) more fully identify and account for the uncertainties in population parameters and (2) account for inherent biases in each data set when estimating population processes of interest (e.g., rates of population changes, Broms et al. 2010). These models are highly adaptable to a variety of data types, including traditional lek counts, productivity indices (e.g., brood counts, wing collections), harvest numbers that are collected at scales of a management unit, as well as localized data from intensive demographic study (e.g., nest survival, annual survival). Recent work has highlighted the use of IPMs to address a variety of scientific questions for grouse (Coates et al. 2014, 2018; McCafferty and Lukacs 2016; Ross et al. 2018; Milligan and McNew 2022). To date, however, IPMs have not been formally applied to state or region-wide population monitoring programs.

4 Habitat Associations

As their name implies, prairie grouse are obligate grassland/shrubland birds. The size, composition, and arrangement of seasonal habitat requirements is critical to maintain viable populations of prairie grouse (Temple 1992; Hoffman et al. 2015). Sensitivity to isolation becomes more pronounced as habitat patches become smaller, especially if barriers prevent movement of individuals among semi-isolated subpopulations (Temple 1992). Specific habitat requirements are discussed below, but there are some general patterns that are consistent across species. Prairie grouse are associated with large expanses of prairie (i.e., grasslands and shrublands) that are relatively unfragmented. For example, large scale crop cultivation and anthropogenic development is associated with population declines for all species of prairie grouse (McNew et al. 2012b; Garton et al. 2016; Runia et al. 2021) and tree encroachment reduces the availability and quality of prairie-chicken habitat (Fuhlendorf et al. 2017).

4.1 Greater Prairie-Chickens

Greater prairie-chickens are primarily found in tallgrass and mixed-grass prairies of the eastern Great Plains (Fig. 9.1). Habitat selection is similar throughout the species’ distribution with less variation than observed with either lesser prairie-chickens or sharp-tailed grouse (Winder et al. 2015). However, greater prairie-chickens show seasonal variation in habitat selection that is associated with their diverse life-history (Londe et al. 2019; Svedarsky et al. 2022). Lek sites are areas characterized by low vegetation (< 15 cm) proximal to nesting cover and this can include crop fields, areas with intensive livestock use, mowed areas, recent burns, or areas with shallow depth to bedrock (Svedarsky et al. 2022). Lek sites are often at higher elevations in landscapes that have variable elevation (Hovick et al. 2015c) and occur in areas with relatively low proportions of cropland and forests (Niemuth 2000, 2003). In the southern Great Plains, greater prairie-chickens show strong avoidance of tree cover during all seasons (Merrill et al. 1999; Lautenbach et al. 2017; Londe et al. 2019).

Females tend to nest within 2 km of active leks (Hovick et al. 2015b), although this may be due to males choosing to lek near nesting cover due to the presence of females (Beehler and Foster 1988). A nest consists of a shallow depression generally with overhead grass cover (Hovick et al. 2015a; Matthews et al. 2013; Fig. 9.2) and intermediate litter depth (Svedarsky 1979). At local scales (i.e., within breeding season home ranges) nest site selection and success of prairie-chickens are strongly associated with the height and density of herbaceous vegetation. Visual obstruction reading (VOR), an index of herbaceous biomass and nest concealment (Robel et al. 1970), is a predominant measure of nesting habitat quality and is commonly associated with both female preference and nesting success (McNew et al. 2014, 2015; Powell et al. 2020). Nest success is often maximized at intermediate measures of VOR. For example, an optimum VOR of 27 cm was reported in Minnesota (Svedarsky 1979), and nest success decreased when VOR exceeded 40 cm (Buhnerkempe et al. 1984). In Kansas, nest site selection and success were maximized when VOR was 30–60 cm (McNew et al. 2014, 2015). An intermediate optimal of VOR indicate some degree of disturbance by fire or grazing is beneficial for nesting prairie-chickens, and this optimal can be realized through moderate livestock stocking rates (Kraft et al. 2021), and specialized rangeland management regimes (McNew et al. 2015; see Sect. 9.5). As nest site selection occurs prior to the current year’s growth of most grasses, residual nesting cover from the previous season is critical. This has large implications for the distribution, area, and timing of grazing and prescribed fire.

Fig. 9.2

Nest sites and brood habitat of prairie grouse. Top: a hatched sharp-tailed grouse nest in grass cover, b sharp-tailed grouse nest in snowberry, and c greater prairie-chicken nest in tallgrass prairie. Bottom: brood habitat of d greater prairie-chickens, e lesser prairie-chickens, and f sharp-tailed grouse are rich in forbs and insects. Photo credits D. Elmore and M. Milligan

Brood-rearing habitat is characterized by areas with abundant forbs and insects that are open at ground level to accommodate the movements of chicks while providing overhead screening cover from predators (Svedarsky 1988; Matthews et al. 2011; Fig. 9.2). Females often move broods from nesting cover to suitable brood-rearing areas and the proximity of nesting and brood-rearing cover likely plays a role in brood success and therefore productivity. The plant communities association with brood-rearing vary regionally (reviewed in Svedarsky et al. 2022). For example, brood habitat has been described as recently-disturbed lowland areas with abundance sedges (Carex spp.), mixed upland vegetation dominated by forbs, and cool-season CRP fields in Minnesota, South Dakota, and Nebraska, respectively (Svedarsky 1979; Norton et al. 2010; Matthews et al. 2013). The plant community type is less important than micro-habitat conditions that provide a mix of cover and food resources (forbs and insects). Disturbances, including fire and livestock grazing, are known to create conditions favorable for broods across the species’ distribution (Svedarsky 1979; Londe et al. 2021a). Heterogeneity of brood cover may also be important; brooding females select patches with higher overhead cover during the heat of the day and limit movement although areas that are more open were used during early morning when temperatures were lower (Londe et al. 2021a).

In general, information on habitat selection during the non-breeding season is lacking for greater prairie-chickens. In southern portions of their distribution, greater prairie-chickens use tallgrass prairie, including areas recently burned during the non-breeding period (Londe et al. 2019). Although they may use available grain crops, greater prairie-chickens in the southern Great Plains do not require them (Horak 1985). In northern portions of their distribution, use of agronomic crops appears more prevalent and has been suggested as leading to expansion of historic distribution (Kobriger 1965). Crops are used during fall and winter if available and can make up a substantial portion of the diet of greater prairie-chickens (Korschgen 1962; Rosenquist and Toepfer 1995). Nevertheless, land uses that reduce large areas of grassland are detrimental to greater prairie-chickens (Runia et al. 2021).

4.2 Lesser Prairie-Chickens

Habitat associations of lesser prairie-chicken are generally more xeric plant communities relative to those of other prairie grouse and vary latitudinally. Lesser prairie-chickens occur in four ecoregions. The mixed-grass prairie ecoregion extends from southwest Kansas through western Oklahoma into the northeast panhandle of Texas. Vegetation in this region consists of mid and tall grasses and often co-dominated by sand sagebrush (Artemesia filifolia) with patchy distributions of deciduous shrubs. The short-grass prairie ecoregion is contained within western Kansas and north of the Arkansas River and estimated to host most of the species’ current abundance (McDonald et al. 2014). Vegetation here is largely sod-forming short-grasses interspersed with considerable acreage of Conservation Reserve Program (CRP) fields. Structurally and compositionally, these fields are similar to mixed grass prairie. The sand shinnery oak prairie ecoregion occupies portions of northwest Texas and eastern New Mexico. Dominated by shinnery oak (Quercus havardii) and mid-tall grass species, this region is perhaps the most susceptible to frequent and severe drought. The sand sagebrush prairie ecoregion spans from southeast Colorado along the Arkansas River into Kansas, and Oklahoma. Vegetation is similar to that of the shinnery oak in terms of soil types and herbaceous plant species, but sand sagebrush is the dominant or co-dominant vegetation.

Despite subtle differences in regional life-histories across ecoregions, lesser prairie-chicken females select nest sites based on similar vegetation structure regardless of plant species present (Hagen et al. 2013). Typically, nests have overhead cover which may be grass or shrub cover depending on the site (Hagen et al. 2013). Greater vegetation density as measured by VOR (25–40 cm) have been linked to nest site selection and nest success across the species’ distribution, and in some cases optimum values have been identified (Hagen et al. 2013, Grisham et al. 2014, Lautenbach et al. 2021). Alternatively, brood habitat tends to have less dense vegetation, more bare ground, and generally has abundant forbs (Bell et al. 2010; Hagen et al. 2006, 2013; Fig. 9.2). Although lesser prairie-chickens have been observed using crop fields (e.g., alfalfa) during the reproductive stages, relatively large tracts of prairie, including shrublands, are required for nesting and rearing broods (Hagen et al. 2004).

Non-reproductive stages and winter habitat use is remarkably similar across the species distribution. Harvested croplands that contain waste grain are often selected for foraging sites when adjacent to prairie (Jones 1963; Hagen et al. 2007b). Shinnery oak plant communities provide acorns and insect galls for food (Jones 1963; Riley et al. 1993). Prairies, including shrubland, are used by lesser prairie-chickens for roosting and loafing when not feeding (Hagen et al. 2007b). In extreme winter conditions, lesser prairie-chickens have been observed feeding on the buds of deciduous shrubs along riparian corridors (Schwilling 1955). Home range size tends to double during the non-breeding season as resource availability declines (Hagen et al. 2007b; Robinson et al. 2018).

4.3 Sharp-Tailed Grouse

Sharp-tailed grouse occur throughout relatively large but variable subclimax brush or shrub-grassland rangeland communities in North America (Aldrich 1963; Johnsgard 2002; Fig. 9.1). As such, specific habitat needs are quite variable throughout the distribution making inference for management difficult to extend beyond a certain geographic area. Nevertheless, some general habitat conditions exist. Sharp-tailed grouse habitat consists of large tracts of native prairie (grasslands and shrublands depending on location and subspecies), wooded draws, and sometimes interspersed with conifers or cropland (Swenson 1985). Like prairie-chickens, habitat of sharp-tailed grouse is generally dominated by herbaceous vegetation (grasses and forbs; Connelly et al. 1998), especially during nesting and brood-rearing periods. Unlike prairie-chickens, during all seasons sharp-tailed grouse use deciduous shrubs which produce high energy food from berries, buds, and leaves (Evans and Dietz 1974), or cover for nests, broods, and adults (Northrup 1991).

Although sharp-tailed grouse have been observed in wheat and alfalfa fields, sharp-tailed grouse prefer native grassland/shrublands (Niemuth and Boyce 2004; Burr et al. 2017; Milligan et al. 2020a). Like prairie-chickens, sharp-tailed grouse nest sites are often characterized by relatively dense cover of grasses but will also nest within stands of shrubs (e.g., snowberry [Symphoricarpos spp.]; Pepper 1972; Marks and Marks 1988; Fig. 9.2); the availability of shrub thickets may offset effects of heavy grazing or drought which can limit herbaceous nest cover (Prose 1987; Kirby and Grosz 1995). Milligan et al. (2020a) found that both nest site selection and nest survival increased asymptotically with VOR with nest survival maximized when visual obstruction was 20–30 cm. Notably, positive effects of VOR extended only 6 m from nests suggesting cover can be relatively patchy for successful nesting. Similarly, brood-rearing habitat is characterized as grasslands having high heterogeneity in herbaceous biomass (e.g., VOR) and composition (e.g., % cover of forbs, grass, bare ground) that provide a combination of concealment from predators, food, and thermal cover for precocial chicks (Manzer and Hannon 2008; Goddard et al. 2009; Geaumont and Graham 2020).

Deciduous and coniferous uplands and riparian areas become increasingly important during the non-breeding season (Nielsen 1982; Northrup 1991; Deeble 1996). Shrubby draws and riparian areas are thought to provide food resources as well as thermal cover (Swenson 1985). Boisvert et al. (2005) observed that home range sizes increased during the fall and winter and included more diverse vegetation types, including crop fields where grouse will feed on waste grain. Nevertheless, research evaluating overwinter habitat use and its effect on survival are lacking.

5 Rangeland Management

5.1 Livestock Grazing

Grazing by livestock is the predominant land use of rangelands occupied by prairie grouse in the U.S. and southern Canada. Livestock do not directly affect prairie grouse demography; that is, livestock have not been demonstrated to kill or displace adults or young prairie grouse. Further, trampling of nests by cattle is infrequent (Pitman et al. 2006b; McNew et al. 2015; Milligan et al. 2020a). However, grazing by livestock can have indirect effects on prairie grouse through manipulation of vegetation and grazing infrastructure (e.g., fences and water tanks). As prairie grouse habitat is principally influenced by the amount, distribution, and types of vegetation on rangelands, management practices and uses that alter plant composition and structure can influence populations.

Not surprisingly, the efficacy of livestock grazing systems for influencing vegetation structure and composition (Briske et al. 2008) and wildlife habitat quality varies widely in the literature (Krausman et al. 2009; Schieltz and Rubenstein 2016). A wide range of stocking rates, season of use, and species of grazer can directly influence the structure and composition of vegetation and indirectly affect prairie grouse. Further, variability in average annual rangeland productivity and yearly variation due to climate lead to dramatic differences in grazing effects. For example, a livestock grazing system that improves habitat quality for nesting prairie grouse in a tallgrass prairie ecosystem (Fuhlendorf et al. 2006; Coppedge et al. 2008) may not have similar effects in the semi-arid mixed-grass prairie (Augustine and Derner 2015). Even within a single grassland ecosystem such as mixed-grass prairie, researchers have found variable responses to livestock grazing management that are apparently influenced by site-specific productivity and precipitation (Kraft et al. 2021).

The quality of prairie grouse habitat is determined by the spatial–temporal composition, structure, and productivity of vegetation that is largely driven by interactions between weather, disturbance (e.g., grazing, fire), and topo-edaphic features. Until recently, evaluations of the effects of grazing were based on correlations and perceptions of managers (e.g., Kessler and Bosch 1982; Klott and Lindzey 1990) or study designs with simplified ‘grazed’ or ‘ungrazed’ treatments (e.g., Kirby and Grosz 1995). More recent research (c.a. 2000–present) has focused on evaluating specific livestock grazing attributes to isolate the effects of weather and livestock grazing in the context of complex working landscapes (Table 9.1). Precipitation within seasons and across multiple years can affect prairie grouse demography directly, but also indirectly through the effects of grazing by livestock on the structure and composition of vegetation (Grisham et al. 2013). For example, season long (i.e., the entirety of the growing season) grazing aimed at 50% forage utilization had positive effects on population growth of lesser prairie-chickens prior to a drought but no measurable effects after a drought in the Sandhills of New Mexico (Fritts et al. 2018).

Table 9.1 Responses of lesser (LEPC), greater (GPCH) prairie-chickens, and sharp-tailed grouse (STGR) to grazing management as reported in the primary peer-reviewed literature, 1970–2021. +, −, and 0 indicated a positive, negative, or no effect of a particular grazing treatment

Stocking rate (i.e., the number of animals on a given amount of land over a certain period; Chap. 4) is probably the single most influential livestock management decision affecting habitat quality for prairie grouse because it is the primary driver of rangeland vegetation biomass, composition, and structure (Briske et al. 2008). Most prairie grouse co-evolved with large herbivores, many of which were nomadic and created pulses of heavy grazing followed by low to no grazing, often for multiyear periods. Low to moderate levels of grazing by livestock have limited effects on prairie grouse. For example, short-duration grazing with low–moderate forage utilization had no measurable effect on nest site selection or nest survival for lesser prairie-chickens (< 25% utilization; Fritts et al. 2016) or sharp-tailed grouse (≤ 50% utilization; Milligan et al. 2020a). High stocking rates at the pasture scale, however, can result in a lack of quality nesting and brood-rearing cover, especially under stocking regimes designed to homogenize livestock utilization across a management unit (e.g., intensive early stocking and annual burning; McNew et al. 2012b, 2015). Importantly, the effects of stocking rate on prairie grouse habitat will vary spatially and temporally due to differences in soil conditions and precipitation. The effects of an animal unit month (AUM) at a site that produces 2,000 kg ha⁻¹ of herbaceous vegetation will differ significantly from a site with 800 kg ha⁻¹. Overall, livestock grazing systems that facilitate, rather than reduce, variation in the composition and structure of vegetation at multiple spatial scales should be the focus of management (Fuhlendorf et al. 2017; Kraft et al. 2021; Sect. 9.5.3) as this not only is similar to historic disturbance patterns with which prairie grouse co-evolved, but also provides prairie grouse with options to meet their various life history requirements.

5.2 Fire

Like grazing, fire can have both positive and negative effects on prairie grouse depending on frequency, size, pattern of burning and grazing, weather conditions, and interactions with other disturbance. If fire occurs in patchy distributions in time and space such that grassland heterogeneity matches prairie grouse habitat requirements, then it will benefit prairie grouse. However, large and frequent fires that remove most nesting cover have been shown to have negative effects on greater prairie-chickens because females select nesting areas characterized by moderate levels of herbaceous biomass (see Sect. 9.4) available in patches that were burned 2–4 years ago (Hovick et al. 2014a; McNew et al. 2015; Lautenbach et al. 2021). Conversely, a lack of fire can often lead to tree encroachment, degrading habitat for greater prairie-chickens (Londe et al. 2019). Similarly, lesser prairie-chickens are negatively affected by lack of fire as tree encroachment is a primary threat (Lautenbach et al. 2017). Much of the research focused on fire and prairie grouse has occurred in the southern Great Plains, however as most prairies in the Great Plains are fire dependent systems that are capable of growing trees in the absence of periodic disturbance, some level of fire is likely needed to maintain prairie-chicken habitat regardless of the location. Sharp-tailed grouse are the most tolerant of trees and northern populations are adapted to parkland prairie vegetation in forested mosaics. The effect of prescribed fire on sharp-tailed grouse is poorly understood. However, the winter use of both deciduous and coniferous trees by sharp-tailed grouse across their distribution suggests a more restrictive use of prescribed fire in wintering areas may be warranted.

5.3 Managing for Heterogeneity

Vegetation heterogeneity, the variability in the composition and structure of plant communities over space and time, is correlated with diversity of both plants and animals (Wiens 1976; Tews et al. 2004). Heterogeneity may be variation in seral stages but also includes within seral stage variability. In fact, heterogeneity occurs and can be measured over multiple spatial scales that can be generalized into four categories relevant to land managers: landscape (> 100 km²), ranch (10–100 km²), among pasture (1–10 km²), and within pasture (< 1 km²; Toombs et al. 2010) and this hierarchy of scales in heterogeneity is important for prairie grouse. Historically, a combination of fire and herbivory by large herds of nomadic grazers maintained a shifting mosaic of heterogeneity at the landscape scale within rangelands (Fuhlendorf et al. 2006). Today, landscape-scale heterogeneity is determined by human land use patterns that are driven by a variety of economic and social-cultural traditions (see Chaps. 3 and 28). At ranch and pasture scales, herbivore grazing interacts with physical conditions (e.g., soils, topography, weather) to determine habitat heterogeneity within remaining grassland/shrubland habitats (Toombs et al. 2010; McNew et al. 2015).

Research has highlighted the importance of patch-level (i.e., within or among pasture) heterogeneity in grassland vegetation for prairie grouse (McNew et al. 2015; Winder et al. 2018; Sullins et al. 2018; Londe et al. 2019; Lautenbach et al. 2021). Rangeland management designed to create or restore patch-level structural heterogeneity to rangelands, such as patch-burn-grazing, has been successfully applied to grasslands in the southern Great Plains and have had positive effects on prairie-chickens relative to grazing systems designed to homogenize forage utilization by livestock (Fig. 9.3). For example, nest survival, adult survival, and habitat use by greater prairie-chickens were increased on rangelands managed with patch-burn grazing relative to intensive early stocking and annual spring burning in the Flint Hills of Kansas (McNew et al. 2015; Winder et al. 2017, 2018). Similar results have been reported for lesser prairie-chickens in mixed-grass prairie of southcentral Kansas (Lautenbach et al. 2021).

Fig. 9.3

Heterogeneous habitat of prairie grouse. Heterogeneity results from both intrinsic constraints on vegetation (e.g., soil, topography, precipitation) and from extrinsic forces (e.g. grazing, fire, herbicide) resulting from rangeland management. Habitat of greater prairie-chickens in Oklahoma (a), lesser prairie-chickens in Kansas (b), Columbian sharp-tailed grouse in Oregon (c) managed with combinations of prescribed fire and grazing. Bottom-right: heterogeneous habitat of plains sharp-tailed grouse in northern mixed-grass prairies grazed moderately by livestock in eastern Montana (d). Heterogeneity in the composition and structure of vegetation at multiple spatial scales benefits prairie grouse. Photo credits D. Elmore, M. Milligan, and N. Richter

Prescribed fire may not be a socially acceptable management tool in some places (Sliwinsky et al. 2018) and research has evaluated whether specialized livestock grazing management can improve habitat heterogeneity for prairie grouse without the use of prescribed fire. Rest-rotation systems that include season-long deferment (e.g., Hormay and Evanko 1958; Chap. 4) in the short-grass prairies of western Kansas provided vegetation heterogeneity that was selected by lesser prairie-chickens (Kraft et al. 2021). In contrast, rest-rotation grazing had no apparent effect on sharp-tailed grouse demography or space use relative to traditional season-long grazing in mixed-grass prairie of eastern Montana (Milligan et al. 2020a, b, c). In these studies, habitat heterogeneity was not influenced by grazing system because stocking rates were low to moderate and study areas were variable in topography and soil conditions (Fig. 9.3). For example, mean and variation of VOR, a key vegetation metric associated with nest survival of prairie grouse (Sect. 9.4), did not differ among pastures managed with season-long, summer rotational, or rest-rotation grazing management (Milligan et al. 2020a; Smith et al. 2020).

The disparity in results of heterogeneity-focused management suggest that relative effects of grazing on habitat selection and demography of prairie grouse are likely spatially variable and dependent on habitat conditions considered at broader spatial scales (McNew et al. 2013). Therefore, best management practices for even a single species within a single ecosystem may vary. Further, although one grazing system or stocking rate may favor certain life history aspects (e.g., nesting), it may not create conditions favorable for another (e.g., brood rearing). The important point is that no one grazing system should be broadly prescribed. As prairie grouse require habitat heterogeneity, rangeland management that promotes vegetation heterogeneity should be the goal (Fuhlendorf et al. 2017), particularly in grasslands that lack inherent heterogeneity due to topo-edaphic variation.

Although vegetation heterogeneity is important to prairie grouse, a hierarchy of habitat requirements constrains the effectiveness of habitat management prescriptions (Johnson 1980; Fuhlendorf et al. 2017). Despite local conditions that may be favorable, landscape factors such as tree encroachment, anthropogenic development, and conversion to crop may make local conditions irrelevant and doom prairie grouse populations (Hagen and Elmore 2016). So, although local management does matter, it does so only in the context of broader landscape characteristics (Toombs et al. 2010; Sect. 9.8).

6 Effects of Disease

Infectious disease is not thought to be a limiting factor to prairie grouse, but parasites are widespread with some populations having consistently high parasite loads (Peterson 2004). Although little evidence exists that parasites regulate prairie grouse populations, it is possible they could negatively affect populations that are already stressed (Peterson 2004). Population cycles of European red grouse (Lagopus lagopus) have been linked to parasitic nematodes (Hudson 1986). Currently there is no evidence of direct or indirect linkages between rangeland management and infectious agents of prairie grouse (Peterson 2004). Unlike greater sage-grouse and ruffed grouse, outbreaks of West Nile virus in prairie grouse have not been reported, or at least no population-level impacts have been observed. In western Europe, tick-borne flavivirus can cause significant economic impacts to livestock and grouse (Burrell et al. 2016); however, prairie grouse are not known to share diseases with livestock in North America.

7 Ecosystem Threats

7.1 Habitat Conversion

Historically, loss of habitat due to conversion to other land uses and land cover has been the primary threat to prairie grouse. Most of the tallgrass prairie in the Midwest has been converted to other uses and large portions of tallgrass and mixed grass prairies in the Great Plains have likewise been converted or fragmented. Much of this conversion has been to crop production and introduced grasses. Although some conversion is still occurring, the vast majority of arable land was altered decades ago which has dramatically lowered carrying capacity for prairie grouse. There is some evidence that introduction of crops up to some threshold may have allowed for greater prairie-chicken distribution expansion in the Great Plains (Johnson and Joseph 1989), yet overall, the conversion to crops has been negative for prairie grouse due to losses of large areas of rangelands. Additionally, tree encroachment due to fire suppression is a significant cause of land conversion that has negatively affected prairie grouse (Fig. 9.4). This has been particularly problematic in the southern Great Plains for both greater and lesser prairie-chickens (Falkowski et al. 2017; Lautenbach et al. 2017; Londe et al. 2019; Hagen et al. 2020). However, tree encroachment is occurring in the northern Great Plains as well where it threatens greater prairie-chickens and to a lesser extent sharp-tailed grouse (Berger and Baydack 1992). Urbanization has reduced significant amounts of prairie grouse habitat (Runia et al. 2021). In most areas occupied by prairie grouse, human density is low and not at high risk of urban development. However, even low-density housing and associated road and powerline network is problematic as prairie grouse have been shown to be sensitive to human development and avoid anthropogenic structures (Pitman et al. 2005). Habitat conversion can range from complete habitat loss such that prairie grouse populations are extirpated, to varying degrees of habitat loss and fragmentation that reduces carrying capacity.

Fig. 9.4

Threats to prairie grouse include loss and fragmentation of grasslands/shrublands, energy development, and rangeland degradation resulting from improper management. Photo credits D. Elmore and L. McNew

7.2 Energy Development

Research results have been mixed in how prairie grouse respond to energy development (Hovick et al. 2014b; Lloyd et al. 2022), which is not surprising given the range of scales, vegetation types, seasons, and structure types evaluated. Research suggests that prairie-chickens avoid roads, powerlines, and oil/gas wells (Hagen 2010; Hovick et al. 2014b; Plumb et al. 2019) with degrees of avoidance varying among structure types and season. For example, greater prairie-chickens in Oklahoma avoided powerlines, roads, and high-density oil wells during the non-breeding period, with few effects noted during the breeding season (Londe et al. 2019). Nesting greater prairie-chickens in Nebraska avoided roads, but habitat selection was not affected by proximity to wind turbines (Harrison et al. 2017; Raynor et al. 2019). Lesser prairie-chickens in Kansas were not affected by a wind facility, although the authors caution that potential effects may have happened prior to data collection as the site was already impacted (LeBeau et al. 2020). Female greater prairie-chickens shifted core use areas away from wind turbines after construction (Winder et al. 2014b) but there was no effect on adult survival (Winder et al. 2014a) or nest site selection and survival within three years of development (McNew et al. 2014). Lek density of lesser prairie-chickens was negatively related to roads and active oil/gas wells in Texas (Timmer et al. 2014). In contrast, sharp-tailed grouse nest success in high density oil and gas areas within the Bakken Oil Field was nearly twice as high as in low-density areas, presumably due to reduced predator occupancy in high-density areas (Burr et al. 2017).

Some of the disparity in results among studies may be due to variability in experimental design, duration of study, and other mediating environmental conditions (e.g., habitat conditions, predator communities) that likely constrain the observable impacts of energy development on grouse (Lloyd et al. 2022). Overall, it appears that prairie grouse can tolerate some level of energy development, but as much of the Great Plains is at risk of becoming industrialized, fragmentation may exceed prairie grouse tolerances. Additional research with standardized designs that occur across gradients of mediating factors are needed. Inferences offered by studies that incorporate pre-construction data, include some form of control, and that are based on longer time-series should be prioritized. Long study durations (> 5 years) are especially important for prairie grouse because high site fidelity to historic leks may result in a delayed response to energy development (Lloyd et al. 2022). Further, little research has been conducted during the non-breeding season, yet limited data suggest this may be the period when prairie grouse are most sensitive to anthropogenic development (Londe et al. 2019).

7.3 Invasive Species

Human land use including livestock grazing, conversion to introduced forages, road construction, and vehicle travel have all contributed to invasive species becoming established across rangelands of North America. Some of these invasive species exist at low to moderate density and are used by prairie grouse and therefore not generally considered problematic for grouse conservation. Such species include dandelion (Taraxacum spp.), salsify (Tragopogon dubius), alfalfa (Medicago sativa), and kochia (Kochia scoparia). However, several species are highly problematic due to their aggressive nature and ability to shift plant communities and suppress more desirable vegetation. These include sericea lespedeza (Lespedeza cuneata), Old World bluestem (Bothriochloa bladhii and B. ischaemum), and exotic bromes (Bromus spp.). These plants often form large monotypic stands which are incapable of providing all the habitat requirements for prairie grouse. For example, although the exotic sericea lespedeza is sometimes used as brood cover during the heat of the day, its seed passes through the gut of galliforms undigested and it can displace more desirable forbs (Baldwin-Blocksome 2006). Control methods of various invasive species vary with some being vulnerable to grazing and or fire. Herbicide (e.g., 2, 4-D, triclopyr) can be effective at killing invasive plants, however collateral damage to nontarget plants is often a substantial problem. Spot application vs pasture level spraying can reduce collateral damage. Additionally, the use of selective herbicides may lessen collateral damage to desired plants. Biological controls have proven effective for some invasive species such as saltcedar (Tamarix spp.), leafy spurge (Euphorbia esula), and musk thistle (Carduus nutans). Regardless of the control used, the goal should be to target problem plants if they are reducing habitat quality for prairie grouse while minimizing loss of desirable plant species.

7.4 Climate Change

Areas occupied by prairie grouse are expected to undergo dramatic climatic shifts by the end of the century. Below we have summarized model output for the distribution of prairie grouse as obtained from Climate Wizard accessed on 30 March 2021 (Girvetz et al. 2009). Rangelands of southern populations of greater and lesser prairie-chickens are expected to become drier by 2100, particularly during summer months. In contrast, northern distributions of greater prairie-chickens and sharp-tailed grouse are projected to become wetter by 2100. These changes can have both positive and negative effects on prairie grouse survival and reproduction depending on exact timing and distribution of precipitation (Londe et al. 2021b). Temperature is also expected to depart from current conditions; the entire distribution of prairie grouse is expected to be warmer during every month of the year. Portions of the northern Great Plains are expected to depart the most from current temperature during the winter months. Extreme temperature departures are expected throughout much of the Great Plains, across the mountain west, and into the Pacific Northwest during the summer. These predictions suggest increased frequency of flash droughts, extended drought, and reduced snow retention, all of which have implications for prairie grouse conservation. Changes in atmospheric CO₂ will also affect plant composition and dominance in the future. While plant composition is affected directly by management, land use, soils and other factors, CO₂ can facilitate some plants such as C3 pathway woody plants (Archer et al. 1995) and may exacerbate tree encroachment in some areas where prairie grouse occur.

The resulting regional effects of changing climates on prairie grouse are unknown but cast uncertainty on whether current species’ distributions will be within the range of environmental tolerances (i.e., niche) for prairie grouse. Increasing temperatures are especially relevant for grouse that evolved and primarily occur in northern climes. Southern populations of prairie grouse may be particularly at risk given evidence that temperature and precipitation directly affect vital rates within and across years (Bell et al. 2010; Grisham et al. 2013; Hovick et al. 2014a, b; Londe et al. 2019). Increased productivity of northern rangelands due to greater precipitation and CO₂ levels may alter habitat management recommendations including the timing, intensity, and duration of livestock grazing and application of prescribed fire to prevent forestation and maintain prairies (Symstad and Leis 2017; Brookshire et al. 2020). Although there is uncertainty with any climate model, it is important to note that change is predicted for most areas where prairie grouse occur. This change should be considered in conservation planning to allow for flexibility in management as well as mitigation for climate change through increased habitat quality, quantity, and spatial distribution.

8 Conservation and Management Actions

8.1 Reversing the Loss and Fragmentation of Grassland

Despite the tremendous variation in vegetation and climatic regimes both among and within the distributions of prairie grouse, one trait is shared among the species—they require large and relatively intact rangeland (i.e., shrubland and/or grassland) landscapes, of which we have few remaining. Although the exact size of landscapes necessary for population persistence is unknown, it is likely tens of thousands of acres based on characteristics of stable populations. Except for sharp-tailed grouse habitat in the far north, the majority of these landscapes are privately owned, and require broad coalitions and partnerships to implement conservation at meaningful scales (Elmore and Dahlgren 2016). The threats facing prairie grouse are as large and diverse as the landscapes on which they depend, devising relevant conservation actions for these species requires a strategic approach (Gerber 2016). First, there must be a recognition that we may not be able to conserve it all and pragmatism is needed to identify the most important areas for conservation. Several efforts have been initiated to prioritize prairie grouse conservation at local, state, and regional levels (Fandel and Hull 2011; Van Pelt et al. 2013). Typically, such efforts first identify population core areas based on breeding bird density or species distribution modeling (Niemuth 2011). Once populations have been mapped and prioritized, then landscapes can be targeted for conservation actions to maintain or increase prairie (Hagen and Elmore 2016; Sullins et al. 2019).

First order goals, such as mapping exercises that demonstrate the extent of the threats (e.g., woodland conversion, energy development) to each core landscape enable managers to strategically manage appropriate resources to maintain that landscape (Sullins et al. 2019; Schindler et al. 2020). Then, second order goals, like land management to improve vegetation communities for prairie grouse and promote heterogeneity would be prudent (Hagen et al. 2013; Hagen and Elmore 2016). Local scale conservation must be implemented in the context of broader landscapes; if surrounded by larger threats, even the best local scale management will be in vain. Landscapes that will be largely converted to anthropogenic development, crops, or tree cover are doomed for prairie grouse regardless of local management.

Nearly ubiquitously, prairie grouse occur in working landscapes and additional resources associated with conservation must be mitigated through cost-share and technical assistance programs to help incentivize landowner participation (Santo et al. 2020; Schindler et al. 2020). Here again, spatial targeting tools can assist in identifying landscapes in which specific outreach (e.g., direct mailings) and extension (e.g., town hall meetings) efforts can be focused to maximize landowner participation in conservation efforts (Sullins et al. 2019; Schindler et al. 2020). Finally, monitoring programs to assess ecological and socio-economic outcomes from conservation actions are vital to ensure effectiveness overtime and to adapt implementation as necessary.

8.2 Habitat Management

Practices and principles within rangeland management are fundamentally dependent upon geographic location (Holechek et al. 2011). The broad spatial extent of North America’s prairie ecosystems accentuates the importance of recognizing innate variability when managing rangelands. Variable productivity among prairie ecosystems, driven largely by regional climate, influences the vegetative characteristics within a specific landscape (Holechek et al. 2011). Even within a single ecosystem, annual variability in precipitation from one growing season to the next significantly affects vegetation structure and composition (Lwiwski et al. 2015). Without accounting for this variation, management actions may not meet wildlife habitat goals.

Despite the temporal and spatial variation within rangelands, prairie grouse have basic life history requirements that must be fulfilled for sustainable populations. All prairie grouse require some level of vegetation heterogeneity to meet nesting, brood rearing, and non-breeding needs. Grazing/rest, prescribed fire, mechanical disturbance, and herbicide application can all be used to meet these habitat requirements but there is no uniform prescription (Sect. 9.5). Managers should seek to understand habitat requirements of target species and apply appropriate disturbances and rest as needed depending on landscape context and environmental variability. This necessitates active and adaptive management across landscapes and years. Management that seeks stability or uniformity is likely to fail to meet prairie grouse objectives in rangelands that are inherently dynamic. Optimal management would be flexible and nimble to ensure that all parts of prairie-grouse habitat requirements are met at sufficiently large scales. Finally, as habitat selection is a hierarchical process, landscape features that render areas unusable, such as those impacted by human development or tree encroachment, will make smaller scale management within those landscapes irrelevant for prairie grouse (Hagen and Elmore 2016; Fuhlendorf et al. 2017).

8.3 Standardizing Population Monitoring

Managers have historically monitored populations of prairie grouse with ground-based lek counts (Bibby et al. 2000) and road-based lek surveys (Best et al. 2003). However, specific protocols vary among states. For example, Hagen et al. (2017) reported that spring monitoring of lesser prairie-chicken populations varied considerably among each of the 5 states where the species occurs, with some states surveying a set of annually monitored leks (e.g., Colorado) and others using road-based surveys with systematic listening stops (e.g., Kansas; Van Pelt et al. 2013). Other states lack standardized survey protocols even within their jurisdictions. Non-standardized approaches make the comparison of common monitoring metrics (e.g., average number of males per lek) across administrative jurisdictions inappropriate and necessitate the use of more complex estimators (Garton et al. 2016). Regardless of survey platform (i.e., air- or ground-based), the development of a standardized and robust population monitoring protocol for prairie grouse should be prioritized so that regional and range-wide evaluations of population trends are possible (Runia et al. 2021).

8.4 Research Needs

In general, information regarding chick (i.e., survival from hatch to fledging) and juvenile survival (i.e., survival from fledging to first breeding) is lacking for prairie grouse. Most previous studies have been limited to flushing broods and have not monitored individual chicks with telemetry to evaluate survival, brood amalgamations, or survival to first breeding (Pitman et al. 2006b). Additionally, factors associated with stable populations are poorly understood, including minimum viable populations, dispersal and filters/barriers to movement, and minimum landscapes (i.e., patch size and connectivity) necessary to support viable populations. Modeling the effect of climate change projections on future distributions and estimated changes in lamba are also needed. Although multiple studies have evaluated the effects of energy development on space use and vital rates during the breeding season, research during the non-breeding season is generally lacking. Further evaluation is needed across species and landscapes before management recommendations are made. Additionally, although there are multiple publications that mention the effects of grazing on prairie grouse, most are either speculative, lack sufficient controls, or were not vetted by peer review (Dettenmaier et al. 2017; Table 9.1). We encourage future assessments of the effects of grazing on prairie grouse to be rigorous, include authors with expertise in rangeland ecology, and be peer reviewed. If site- and management-specific parameters are not considered empirically as covariates, then detailed descriptions of the study systems (e.g., soil or ecological sites, annual precipitation; timing, duration, and intensity of livestock grazing) should be provided so that reported effects can be put into context. Finally, most studies have been limited to short durations with inconsistent designs among studies. Multiple concurrent studies across variable landscapes using standardized approaches are needed to sort out effects of interest from site-specific variability (Lloyd et al. 2022).