Sage-grouse Populations Research Articles

Vitals rates and seasonal movements of two isolated greater sage-grouse populations in Utah's West Desert

Declines in greater sage-grouse (Centrocercus urophasianus; hereafter, sagegrouse) populations in Utah over the last century parallel range-wide trends. However, little is known about the ecology of sage-grouse populations that inhabit Utah’s naturally fragmented habitats. Utah’s West Desert sage-grouse populations occupy sagebrush (Artemisia spp.) habitats that are geographically separated by the Great Salt Lake, and largely confined to the Sheeprock and Deep Creek watersheds. From 2005 to 2006, we monitored sagegrouse that were radio-collared in each watershed to determine the factors affecting the vital rates in these isolated populations. Livestock grazing by domestic cattle was the dominate land use, and mammalian predator control for livestock protection was conducted in both watersheds. Corvid control was conducted only in the Sheeprock watershed. During the study, we identified 6 leks that had not been previously documented. Seasonal migration patterns for individual radio-collared sage-grouse in both watersheds varied across the sites. Habitat structure metrics were similar at brood-rearing and random sites for both areas. Nesting and brood success and the ratio of chicks per successful brood were higher for both populations in 2005 than 2006. We attributed these annual differences in vital rates to seasonal variation in precipitation. Spring precipitation in 2005 was twice the 30-year average following a 5 year drought. However, chick recruitment estimates for both populations regardless of year were lower than reported in the published literature. Adult sage-grouse survival rate estimates in Sheeprock and Deep Creek watersheds were lower and higher, respectively, than published reports indicated. These differences may reflect a difference in meso-predators communities. Sage-grouse conservation strategies in both areas should continue to emphasize protection of brood-rearing and seasonal habitat, but the risk of population extirpation as a consequence of extended droughts predicted by climate change models and the invasion of small mesopredators may remain problematic for these populations.

Response of a small population of greater sage-grouse to tree removal: implications of limiting factors

In Utah, greater sage-grouse (Centrocercus urophasianus; hereafter, sage- grouse) range has been reduced to 50% of what is considered historical availability due to habitat degradation and loss. In an effort to improve sage-grouse habitat in southern Utah, the U.S. Bureau of Land Management (BLM) conducted a tree-removal treatment in 2005. We conducted a study to determine if (a) the tree-removal treatment was effective at creating new sage-grouse habitat, and (b) if characteristics of used habitat were similar to those reported in previous literature. The treatment resulted in increased abundance of grasses and forbs. Additionally, shrub percentage cover and height was not negatively affected by the treatment. Sage-grouse used the treated areas more than expected based on availability within the first year of the treatment. The vegetation resulting from the treatment used by sage-grouse in all seasons was lower in percentage shrub, grass, forb composition, and average height than the range of previously reported habitats for late-brood rearing, fall and winter seasons of use. Sage-grouse's quick positive response to the treated area suggests that suitable habitat is limited in this region.

Declining populations of greater sage-grouse: where and why

Declining populations of greater sage-grouse: where and why

Ecology of greater sage-grouse populations inhabiting the northwestern Wyoming Basin

Ecology of greater sage-grouse populations inhabiting the northwestern Wyoming Basin

Weather, habitat composition, and female behavior interact to modify offspring survival in Greater Sage-Grouse.

Weather is a source of environmental variation that can affect population vital rates. However, the influence of weather on individual fitness is spatially heterogeneous and can be driven by other environmental factors, such as habitat composition. Therefore, individuals can experience reduced fitness (e.g., decreased reproductive success) during poor environmental conditions through poor decisions regarding habitat selection. This requires, however, that habitat selection is adaptive and that the organism can correctly interpret the environmental cues to modify habitat use. Greater Sage-Grouse (Centrocercus urophasianus) are an obligate of the sagebrush ecosystems of western North America, relying on sagebrush for food and cover. Greater Sage-Grouse chicks, however, require foods with high nutrient content (i.e.,forbs and insects), the abundance of which is both temporally and spatially dynamic and related primarily to water availability. Our goal was to assess whether nest site selection and movements of broods by females reduced the negative effect of drought on offspring survival. As predicted, chick survival was negatively influenced by drought severity. We found that sage-grouse females generally preferred to nest and raise their young in locations where their chicks would experience higher survival. We also found that use of habitats positively associated with chick survival were also positively associated with drought severity, which suggests that females reduced drought impacts on their dependent young by selecting more favorable environments during drought years. Although our findings suggest that female nest site selection and brood movement rates can reduce the negative effects of drought on early offspring survival, the influence of severe drought conditions was not completely mitigated by female behavior, and that drought conditions should be considered a threat to Greater Sage-Grouse population persistence.

Effectiveness of Wyoming's Sage-Grouse Core Areas: Influences on Energy Development and Male Lek Attendance.

Greater sage-grouse (Centrocercus urophasianus) populations have declined across their range due to human-assisted factors driving large-scale habitat change. In response, the state of Wyoming implemented the Sage-grouse Executive Order protection policy in 2008 as a voluntary regulatory mechanism to minimize anthropogenic disturbance within defined sage-grouse core population areas. Our objectives were to evaluate areas designated as Sage-grouse Executive Order Core Areas on: (1) oil and gas well pad development, and (2) peak male lek attendance in core and non-core sage-grouse populations. We conducted our evaluations at statewide and Western Association of Fish and Wildlife Agencies management zone (MZ I and MZ II) scales. We used Analysis of Covariance modeling to evaluate change in well pad development from 1986-2014 and peak male lek attendance from 958 leks with consistent lek counts within increasing (1996-2006) and decreasing (2006-2013) timeframes for Core and non-core sage-grouse populations. Oil and gas well pad development was restricted in Core Areas. Trends in peak male sage-grouse lek attendance were greater in Core Areas compared to non-core areas at the statewide scale and in MZ II, but not in MZ I, during population increase. Trends in peak male lek attendance did not differ statistically between Core and non-core population areas statewide, in MZ I, or MZ II during population decrease. Our results provide support for the effectiveness of Core Areas in maintaining sage-grouse populations in Wyoming, but also indicate the need for increased conservation actions to improve sage-grouse population response in MZ I.

Wildfire, climate, and invasive grass interactions negatively impact an indicator species by reshaping sagebrush ecosystems

Iconic sagebrush ecosystems of the American West are threatened by larger and more frequent wildfires that can kill sagebrush and facilitate invasion by annual grasses, creating a cycle that alters sagebrush ecosystem recovery post disturbance. Thwarting this accelerated grass-fire cycle is at the forefront of current national conservation efforts, yet its impacts on wildlife populations inhabiting these ecosystems have not been quantified rigorously. Within a Bayesian framework, we modeled 30 y of wildfire and climatic effects on population rates of change of a sagebrush-obligate species, the greater sage-grouse, across the Great Basin of western North America. Importantly, our modeling also accounted for variation in sagebrush recovery time post fire as determined by underlying soil properties that influence ecosystem resilience to disturbance and resistance to invasion. Our results demonstrate that the cumulative loss of sagebrush to direct and indirect effects of wildfire has contributed strongly to declining sage-grouse populations over the past 30 y at large spatial scales. Moreover, long-lasting effects from wildfire nullified pulses of sage-grouse population growth that typically follow years of higher precipitation. If wildfire trends continue unabated, model projections indicate sage-grouse populations will be reduced to 43% of their current numbers over the next three decades. Our results provide a timely example of how altered fire regimes are disrupting recovery of sagebrush ecosystems and leading to substantial declines of a widespread indicator species. Accordingly, we present scenario-based stochastic projections to inform conservation actions that may help offset the adverse effects of wildfire on sage-grouse and other wildlife populations.

Conserving the Greater Sage-Grouse: A Social-Ecological Systems Case Study from the California-Nevada Region

The Endangered Species Act (ESA) continues to serve as one of the most powerful and contested federal legislative mandates for conservation. In the midst of heated debates, researchers, policy makers, and conservation practitioners champion the importance of cooperative conservation and social-ecological systems approaches, which forge partnerships at multiple levels and scales to address complex ecosystem challenges. However, few real-world examples exist to demonstrate how multifaceted collaborations among stakeholders who share a common goal of conserving at-risk species may be nested within a systems framework to achieve social and ecological goals. Here, we present a case study of Greater Sage-grouse (Centrocercus urophasianus) conservation efforts in the “Bi-State” region of California and Nevada, United States. Using key-informant interviews, we explored dimensions and drivers of this landscape-scale conservation effort. Three themes emerged from the interviews, including 1) ESA action was transformed into opportunity for system-wide conservation; 2) a diverse, locally based partnership anchored collaboration and engagement across multiple levels and scales; and 3) best-available science combined with local knowledge led to “certainty of effectiveness and implementation”—the criteria used by the US Fish and Wildlife Service to evaluate conservation efforts when making listing decisions. Ultimately, collaborative conservation through multistakeholder engagement at various levels and scales led to proactive planning and implementation of conservation measures and precluded the need for an ESA listing of the Bi-State population of Greater Sage-grouse. This article presents a potent example of how a systems approach integrating policy, management, and learning can be used to successfully overcome the conflict-laden and “wicked” challenges that surround at-risk species conservation.

Effects of common raven and coyote removal and temporal variation in climate on greater sage-grouse nesting success

Predator removal has been simultaneously proposed and criticized as a mitigation measure for low reproductive rates of prey species, including greater sage-grouse (Centrocercus urophasianus; hereafter “sage-grouse”). Depredation of sage-grouse nests can limit their productivity. In Wyoming, lethal removal of common ravens (Corvus corax: hereafter “ravens”) and coyotes (Canis latrans) has been conducted by USDA/APHIS/Wildlife Services (WS) for the protection of livestock. During 2008–2011, we evaluated sage-grouse nest success in study sites (1) where WS initiated a raven removal program, (2) WS removed coyotes, and (3) WS did not manipulate ravens and/or coyotes. Precipitation and temperature were analyzed individually and as interactive effects with coyote removal numbers as sources of annual variation in nest success. Over the course of our study, raven densities decreased at study sites with WS raven removal, while sage-grouse nest success in those study sites was higher during years with reduced raven density. Temperature effects on nest success were dependent on timing with successful nests having cooler temperatures prior to the nesting season (conditions promoting water retention and grass growth) and warmer temperatures the week before nest fate (conducive to degradation of sage-grouse odorants used by mammalian predators). Lower nest success was associated with more lethally removed coyotes interacting with greater precipitation suggesting mesopredator release. Raven removal may have a place in sage-grouse management as an interim mitigation measure when sage-grouse populations are subjected to high densities of ravens. However, long-term solutions are necessary, such as reducing supplemental food sources and perch structures used by ravens.

Latent spatial models and sampling design for landscape genetics

We propose a spatially-explicit approach for modeling genetic variation across space and illustrate how this approach can be used to optimize spatial prediction and sampling design for landscape genetic data. We propose a multinomial data model for categorical microsatellite allele data commonly used in landscape genetic studies, and introduce a latent spatial random effect to allow for spatial correlation between genetic observations. We illustrate how modern dimension reduction approaches to spatial statistics can allow for efficient computation in landscape genetic statistical models covering large spatial domains. We apply our approach to propose a retrospective spatial sampling design for greater sage-grouse (Centrocercus urophasianus) population genetics in the western United States.

Assessing Greater Sage-Grouse Selection of Brood-Rearing Habitat Using Remotely-Sensed Imagery: Can Readily Available High-Resolution Imagery Be Used to Identify Brood-Rearing Habitat Across a Broad Landscape?

Greater sage-grouse populations have decreased steadily since European settlement in western North America. Reduced availability of brood-rearing habitat has been identified as a limiting factor for many populations. We used radio-telemetry to acquire locations of sage-grouse broods from 1998 to 2012 in Strawberry Valley, Utah. Using these locations and remotely-sensed NAIP (National Agricultural Imagery Program) imagery, we 1) determined which characteristics of brood-rearing habitat could be used in widely available, high resolution imagery 2) assessed the spatial extent at which sage-grouse selected brood-rearing habitat, and 3) created a predictive habitat model to identify areas of preferred brood-rearing habitat. We used AIC model selection to evaluate support for a list of variables derived from remotely-sensed imagery. We examined the relationship of these explanatory variables at three spatial extents (45, 200, and 795 meter radii). Our top model included 10 variables (percent shrub, percent grass, percent tree, percent paved road, percent riparian, meters of sage/tree edge, meters of riparian/tree edge, distance to tree, distance to transmission lines, and distance to permanent structures). Variables from each spatial extent were represented in our top model with the majority being associated with the larger (795 meter) spatial extent. When applied to our study area, our top model predicted 75% of naïve brood locations suggesting reasonable success using this method and widely available NAIP imagery. We encourage application of our methodology to other sage-grouse populations and species of conservation concern.

Seasonal movements of greater sage-grouse populations in Utah: Implications for species conservation

Greater sage-grouse (Centrocercus urophasianus; sage-grouse) is considered an umbrella species for sagebrush (Artemisia spp.) landscapes in western North America. In 2015, the U.S. Fish and Wildlife Service determined sage-grouse unwarranted for protection under the Endangered Species Act (1973) because of conservation actions in priority areas. Understanding seasonal movements is key to delineation and assessment of priority conservationareas.Wemonitored radiomarked sage-grouse from1998 to2013 throughoutUtah,USA,to determine seasonal movements. Maximum distances from nearest lek to nesting, summer, and winter locations across all radiomarkedgrouse averaged2.20 km(90thpercentile1⁄4 5.06 km), 3.93 km(90thpercentile1⁄4 8.45 km), and3.76 km(90thpercentile1⁄4 7.15 km), respectively.Maximummovements fromnest to summer,nest towinter, and between summer and winter locations across all radiomarked grouse averaged 5.77 km (90th percentile1⁄4 13.60 km), 11.77 km (90th percentile1⁄4 26.36 km), and 14.75 km (90th percentile1⁄4 30.77 km), respectively. Maximum distance from lek of capture to summer locations was greater for males than females, whereas femalesmoved farther thanmales fromlek towinter andsummer towinter locations.Adult femalesmoved farther than yearlings from lek to nest and summer towinter areas. The state ofUtah’s Sage-GrouseManagement Areas included approximately 85% of the radiotelemetry seasonal locations and >95% when weighted by lek counts.Our results suggest that seasonalmovements could be facilitatedby increasingusable habitat space through management actions, as emphasized in Utah’s sage-grouse plan. 2016 The Wildlife Society.

Microsite selection and survival of greater sage-grouse nests in south-central Wyoming

Greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) populations have declined across North America because of degradation of sagebrush (Artemisia spp.) ecosystems; thus, management for sage-grouse habitat is a high priority. Expansion of some energy development has put additional pressures on sage-grouse populations and their habitats. However, little is known about the effects wind energy development may have on sage-grouse populations. Population dynamics of sage-grouse are partially related to nest success, which may be influenced by the quality of nesting habitat. Consequently, knowledge of vegetation and structural characteristics associated with selection and survival of sage-grouse nests would help inform management decisions to improve nest success. As part of a study quantifying greater sage-grouse demographics prior to construction of a wind energy facility, we monitored female sage-grouse equipped with 30-g solar Argos global positioning system platform transmitter terminals during the breeding season in Carbon County, Wyoming to assess selection and survival of nests at nest area (30-m radius), nest patch (5-m radius), and nest bowl scales. Sage-grouse selected nest sites with increased visual obstruction from 22.9–45.7 cm in height at all scales, less forb cover at the nest area, and more sagebrush cover at the nest patch. Survival of nests to 27 days (i.e., incubation period) was 43.3% (95% CI: 31.8–59.1%) in 2011 (n = 49), 33.2% (95% CI: 21.5–51.3%) in 2012 (n = 40), and 25.1% (95% CI: 15.0–42.0%) in 2013 (n = 39). Grass height had a positive association with survival of nests at the nest area and nest patch, canopy cover of bunchgrasses and sagebrush had an interactive effect on survival of nests at the nest patch, and visual obstruction from 0–22.9 cm in height had a positive relationship with survival of nests at the nest bowl. The standardized precipitation-evapotranspiration index (SPEI), an index of drought, from the previous growing season was also negatively correlated with survival of nests. Our results suggest management for nesting sage-grouse should focus on a heterogeneous compilation of tall bunchgrasses >15 cm and patches of sagebrush cover >30%. Management for grasses >15 cm tall should be especially diligent during drought years, given SPEI was associated with nest survival the following year. Although there could be other factors important to selection or survival of nests that we did not evaluate, our results suggest scale-dependent management strategies at the microsite level may not be necessary. We encourage researchers and managers to use our baseline results in a before–after control-impact design with future, post-construction data to determine the potential effects of wind energy development on selection and survival of sage-grouse nests. © 2016 The Wildlife Society.

Integrating spatially explicit indices of abundance and habitat quality: an applied example for greater sage-grouse management.

Summary Predictive species distributional models are a cornerstone of wildlife conservation planning. Constructing such models requires robust underpinning science that integrates formerly disparate data types to achieve effective species management.Greater sage‐grouse Centrocercus urophasianus, hereafter ‘sage‐grouse’ populations are declining throughout sagebrush‐steppe ecosystems in North America, particularly within the Great Basin, which heightens the need for novel management tools that maximize the use of available information.Herein, we improve upon existing species distribution models by combining information about sage‐grouse habitat quality, distribution and abundance from multiple data sources. To measure habitat, we created spatially explicit maps depicting habitat selection indices (HSI) informed by >35 500 independent telemetry locations from >1600 sage‐grouse collected over 15 years across much of the Great Basin. These indices were derived from models that accounted for selection at different spatial scales and seasons. A region‐wide HSI was calculated using the HSI surfaces modelled for 12 independent subregions and then demarcated into distinct habitat quality classes.We also employed a novel index to describe landscape patterns of sage‐grouse abundance and space use (AUI). The AUI is a probabilistic composite of the following: (i) breeding density patterns based on the spatial configuration of breeding leks and associated trends in male attendance; and (ii) year‐round patterns of space use indexed by the decreasing probability of use with increasing distance to leks. The continuous AUI surface was then reclassified into two classes representing high and low/no use and abundance. Synthesis and applications. Using the example of sage‐grouse, we demonstrate how the joint application of indices of habitat selection, abundance and space use derived from multiple data sources yields a composite map that can guide effective allocation of management intensity across multiple spatial scales. As applied to sage‐grouse, the composite map identifies spatially explicit management categories within sagebrush steppe that are most critical to sustaining sage‐grouse populations as well as those areas where changes in land use would likely have minimal impact. Importantly, collaborative efforts among stakeholders guide which intersections of habitat selection indices and abundance and space use classes are used to define management categories. Because sage‐grouse are an umbrella species, our joint‐index modelling approach can help target effective conservation for other sagebrush obligate species and can be readily applied to species in other ecosystems with similar life histories, such as central‐placed breeding.

Large-scale control site selection for population monitoring: An example assessing sage-grouse trends

Human impacts on wildlife populations are widespread and prolific and understanding wildlife responses to human impacts is a fundamental component of wildlife management. The first step to understanding wildlife responses is the documentation of changes in wildlife population parameters, such as population size. Meaningful assessment of population changes in potentially impacted sites requires the establishment of monitoring at similar, nonimpacted, control sites. However, it is often difficult to identify appropriate control sites in wildlife populations. We demonstrated use of Geographic Information System (GIS) data across large spatial scales to select biologically relevant control sites for population monitoring. Greater sage-grouse (Centrocercus urophasianus; hearafter, sage-grouse) are negatively affected by energy development, and monitoring of sage-grouse population within energy development areas is necessary to detect population-level responses. We used population data (1995–2012) from an energy development area in Wyoming, USA, the Atlantic Rim Project Area (ARPA), and GIS data to identify control sites that were not impacted by energy development for population monitoring. Control sites were surrounded by similar habitat and were within similar climate areas to the ARPA. We developed nonlinear trend models for both the ARPA and control sites and compared long-term trends from the 2 areas. We found little difference between the ARPA and control sites trends over time. This research demonstrated an approach for control site selection across large landscapes and can be used as a template for similar impact-monitoring studies. It is important to note that identification of changes in population parameters between control and treatment sites is only the first step in understanding the mechanisms that underlie those changes. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Microhabitat Selection of Brood-Rearing Sites by Greater Sage-Grouse in Carbon County, Wyoming

Abstract. Declines in Greater Sage-Grouse (Centrocercus urophasianus, hereafter sage-grouse) populations could be attributed to low chick survival, which may be influenced by the availability of food and cover at sites used by females rearing broods. Habitat attributes important to broods may vary regionally; thus, it is necessary to understand factors affecting regional sage-grouse brood-rearing site selection, especially when estimating the impacts of development. We monitored brood-rearing female sage-grouse equipped with solar Argos Global Positioning System Platform Transmitter Terminals from 2011 to 2013 to assess microhabitat selection by broods in Carbon County, Wyoming. We measured vegetation and arthropod characteristics at diurnal sites used by broods (n = 42 in 2011, n = 31 in 2012, n = 32 in 2013) and at 3 paired-random sites associated with each used site (n = 315), located 50 m, 250 m, and 500 m from the used site. We fit conditional logistic models within an information-theoretic framework...

Nest Success of Gunnison Sage-Grouse in Colorado, USA.

Gunnison Sage-Grouse (Centrocercus minimus) is a species of concern for which little demographic information exists. To help fill this information gap, we investigated factors affecting nest success in two populations of Gunnison Sage-Grouse. We assessed the relative effects of (1) vegetation characteristics (e.g., shrub height, shrub cover, grass cover, and grass height), (2) temporal factors (e.g., year, timing of incubation initiation, and nest age), (3) precipitation, and (4) age of the nesting female (yearling or adult) on nest success rates. We found 177 nests in the Gunnison Basin population (that contains 85–90% of the species) from 2005–2010 and 20 nests in the San Miguel population (that contains < 10% of the species) from 2007–2010. Temporal factors had the greatest impact on nest success compared to vegetation characteristics, precipitation, and female age. Nest success varied considerably among years ranging from 4.0%-60.2% in Gunnison Basin and from 12.9%- 51.9% in San Miguel. Nests that were initiated earlier in the breeding season had higher nest success (at least one egg hatches). Daily nest survival rates decreased during the course of incubation. None of the vegetation characteristics we examined were strongly related to nest success.

Greater Sage-Grouse and Range Management: Insights from a 25-Year Case Study in Utah and Wyoming

Conservation of sagebrush (Artemisia spp.) systems is one of the most difficult and pressing concerns in western North America. Sagebrush obligates, such as greater sage-grouse (Centrocercus urophasianus; hereafter sage-grouse), have experienced population declines as sagebrush systems have degraded. Science-based management is crucial to improve certainty in range management practices. Although large-scale implementation of management regimens within an experimental design is difficult, long-term case studies provide opportunities to improve learning and develop and refine hypotheses. We used 25 years of data across three large landscapes in northern Utah and southwestern Wyoming to assess sage-grouse population change and corresponding land management differences in a case study design. Sage-grouse lek counts at our Deseret Land and Livestock (DLL) study site increased relative to surrounding populations in correspondence with the implementation of small-acreage sagebrush treatments designed to reduce shrub cover and increase herbaceous understory within a prescriptive grazing management framework. The higher lek counts were sustained for nearly 15 years. However, with continued sagebrush treatments and the onset of adverse winter conditions, DLL lek counts declined to levels consistent with surrounding areas. During summer, DLL sage-grouse broods used plots of small, treated sagebrush mosaics more than untreated reference sites. We hypothesize that sagebrush treatments on DLL increased availability of grasses and forbs to sage-grouse, similar to other studies, but that cumulative annual reductions in sagebrush may have reduced availability of sagebrush cover for sage-grouse seasonal needs at DLL, especially when extreme winter weather occurred.

Captive-rearing of Gunnison sage-grouse from egg collection to adulthood to foster proactive conservation and recovery of a conservation-reliant species.

Gunnison sage-grouse (Centrocercus minimus) are distributed across southwestern Colorado and southeastern Utah, United States. Their distribution has decreased over the past century and the species has been listed as threatened by the U.S. Fish and Wildlife Service. Reduced genetic diversity, small population size, and isolation may affect Gunnison sage-grouse population persistence. Population augmentation can be used to counteract or mitigate these issues, but traditional translocation efforts have yielded mixed, and mostly unsuccessful, results. Captive-rearing is a viable, although much debated, conservation approach to bolster wild conservation-reliant species. Although there have been captive-rearing efforts with greater sage-grouse (C. urophasianus), to date, no information exists about captive-rearing methods for Gunnison sage-grouse. Therefore, we investigated techniques for egg collection, artificial incubation, hatch, and captive-rearing of chicks, juveniles, subadults, and adults for Gunnison sage-grouse. In 2009 we established a captive flock that produced viable eggs. From 2009-2011, we collected and artificially incubated 206 Gunnison sage-grouse eggs from 23 wild and 14 captive females. Our hatchability was 90%. Wild-produced eggs were heavier than captive-produced eggs and lost mass similarly during incubation. We produced 148 chicks in captivity and fed them a variety of food sources (e.g. invertebrates to commercial chow). Bacterial infections were the primary cause of chick mortality, but we successfully reduced the overall mortality rate during the course of our study. Conservationists and managers should consider the utility in developing a captive-rearing program or creating a captive population as part of a proactive conservation effort for the conservation-reliant Gunnison sage-grouse.

Captive rearing sage-grouse for augmentation of surrogate wild broods: Evidence for success

Both species of North American sage-grouse (Centrocercus spp.) have experienced declines in distribution and abundance. Translocation of adult birds from a stable population to a small or declining population has been a management tool used by wildlife managers to support population persistence in these areas. Captive rearing chicks and releasing them into wild surrogate broods is an untested alternative to augment declining populations of sage-grouse. We developed techniques to successfully rear sage-grouse chicks in captivity, evaluated explanatory variables that could influence hatch and captive-rearing success, and estimated the survival of domestically hatched (DH) chicks to 28 days of age following introduction to a surrogate wild brood. We collected 304 eggs from radiomarked female greater sage-grouse (C. urophasianus) during 2004–2007 in 3 study areas in northwestern Colorado. Estimated hatching success of collected eggs was 0.745 (SE = 0.022, 95% CI = 0.700–0.786) and was negatively influenced by the number of days an egg was stored and the percent egg weight loss that occurred during storage and incubation. We monitored 175 DH chicks in captivity for 1–10 days before introduction and adoption into surrogate wild broods. Model-averaged captive-rearing success was 0.792 (SE = 0.045, 95% CI = 0.686–0.865) across years, and was positively influenced by initial chick mass at hatch and daily weight gain in captivity but negatively influenced by the number of days the egg was stored and advancing hatch date. We were able to radiomark and monitor 133 DH chicks adopted into surrogate wild broods until 28 days of age. Eighty-eight percent of DH chicks were successfully adopted within 24 hours. Our overall estimate of DH chick survival to 28 days (0.423; 95% CI = 0.257–0.587) was comparable to published wild-hatched chick survival. Predation and exposure-related deaths accounted for 26.3% and 25.6% of the known fates, respectively. Our captive-rearing protocols and techniques were successful for collecting greater sage-grouse eggs, hatching and rearing chicks in captivity, and releasing chicks into wild surrogate broods. This success further implies that captive rearing and release can be a potential management strategy to demographically and genetically reinforce or augment small populations of sage-grouse. © 2015 The Wildlife Society.