| Vocal and anatomical evidence for two-voiced sound production in the greater sage-grouse Centrocercus urophasianus | Krakauer, Alan H. | 2009 |
Keywordsacoustic location system Galliformes lek microphone array syrinx syringeal muscle AbstractGreater sage-grouse, Centrocercus urophasianus, have been a model system in studies of sexual selection and lek evolution. Mate choice in this species depends on acoustic displays during courtship, yet we know little about how males produce these sounds. Here we present evidence for previously undescribed two-voiced sound production in the sage-grouse. We detected this 'double whistle' (DW) using multi-channel audio recordings combined with video recordings of male behavior. Of 28 males examined, all males produced at least one DW during observation; variation in DW production did not correlate with observed male mating success. We examined recordings from six additional populations throughout the species' range and found evidence of DW in all six populations, suggesting that the DW is widespread. To examine the possible mechanism of DW production, we dissected two male and female sage-grouse; the syrinx in both sexes differed noticeably from that of the domestic fowl, and notably had two sound sources where the bronchi join the syrinx. Additionally, we found males possess a region of pliable rings at the base of the trachea, as well as a prominent syringeal muscle that is much reduced or absent in females. Experiments with a live phonating bird will be necessary to determine how the syrinx functions to produce the whistle, and whether the DW might be the result of biphonation of a single sound source. We conclude that undiscovered morphological and behavioral complexity may exist even within well-studied species, and that integrative research approaches may aid in the understanding of this type of complexity. AuthorsKrakauer, Alan H.; Tyrrell, Maura; Lehmann, Kenna; Losin, Neil; Goller, Franz; Patricelli, Gail L. Year Published2009 PublicationJournal of Experimental Biology LocationsDOI10.1242/jeb.033076 |
| Mapping Oil and Gas Development Potential in the US Intermountain West and Estimating Impacts to Species | Copeland, Holly E. | 2009 |
KeywordsNo keywords available AbstractBackground: Many studies have quantified the indirect effect of hydrocarbon-based economies on climate change and biodiversity, concluding that a significant proportion of species will be threatened with extinction. However, few studies have measured the direct effect of new energy production infrastructure on species persistence.Methodology/Principal Findings: We propose a systematic way to forecast patterns of future energy development and calculate impacts to species using spatially-explicit predictive modeling techniques to estimate oil and gas potential and create development build-out scenarios by seeding the landscape with oil and gas wells based on underlying potential. We illustrate our approach for the greater sage-grouse (Centrocercus urophasianus) in the western US and translate the build-out scenarios into estimated impacts on sage-grouse. We project that future oil and gas development will cause a 7-19 percent decline from 2007 sage-grouse lek population counts and impact 3.7 million ha of sagebrush shrublands and 1.1 million ha of grasslands in the study area.Conclusions/Significance: Maps of where oil and gas development is anticipated in the US Intermountain West can be used by decision-makers intent on minimizing impacts to sage-grouse. This analysis also provides a general framework for using predictive models and build-out scenarios to anticipate impacts to species. These predictive models and build-out scenarios allow tradeoffs to be considered between species conservation and energy development prior to implementation. AuthorsCopeland, Holly E.; Doherty, Kevin E.; Naugle, David E.; Pocewicz, Amy; Kiesecker, Joseph M. Year Published2009 PublicationPLOS One LocationsDOI10.1371/journal.pone.0007400 |
| A Currency for Offsetting Energy Development Impacts: Horse-Trading Sage-Grouse on the Open Market | Doherty, Kevin E. | 2010 |
KeywordsNo keywords available AbstractBackground: Biodiversity offsets provide a mechanism to compensate for unavoidable damages from new energy development as the U. S. increases its domestic production. Proponents argue that offsets provide a partial solution for funding conservation while opponents contend the practice is flawed because offsets are negotiated without the science necessary to backup resulting decisions. Missing in negotiations is a biologically-based currency for estimating sufficiency of offsets and a framework for applying proceeds to maximize conservation benefits.Methodology/Principal Findings: Here we quantify a common currency for offsets for greater sage-grouse (Centrocercus urophasianus) by estimating number of impacted birds at 4 levels of development commonly permitted. Impacts were indiscernible at 1-12 wells per 32.2 km(2). Above this threshold lek losses were 2-5 times greater inside than outside of development and bird abundance at remaining leks declined by -32 to -77%. Findings reiterated the importance of time-lags as evidenced by greater impacts 4 years after initial development. Clustering well locations enabled a few small leks to remain active inside of developments.Conclusions/Significance: Documented impacts relative to development intensity can be used to forecast biological tradeoffs of newly proposed or ongoing developments, and when drilling is approved, anticipated bird declines form the biological currency for negotiating offsets. Monetary costs for offsets will be determined by true conservation cost to mitigate risks such as sagebrush tillage to other populations of equal or greater number. If this information is blended with landscape level conservation planning, the mitigation hierarchy can be improved by steering planned developments away from conservation priorities, ensuring compensatory mitigation projects deliver a higher return for conservation that equate to an equal number of birds in the highest priority areas, provide on-site mitigation recommendations, and provide a biologically based cost for mitigating unavoidable impacts. AuthorsDoherty, Kevin E.; Naugle, David E.; Evans, Jeffrey S. Year Published2010 PublicationPLOS One LocationsDOI10.1371/journal.pone.0010339 |
| Identifying and Prioritizing Greater Sage-Grouse Nesting and Brood-Rearing Habitat for Conservation in Human-Modified Landscapes | Dzialak, Matthew R. | 2011 |
KeywordsNo keywords available AbstractBackground: Balancing animal conservation and human use of the landscape is an ongoing scientific and practical challenge throughout the world. We investigated reproductive success in female greater sage-grouse (Centrocercus urophasianus) relative to seasonal patterns of resource selection, with the larger goal of developing a spatially-explicit framework for managing human activity and sage-grouse conservation at the landscape level.Methodology/Principal Findings: We integrated field-observation, Global Positioning Systems telemetry, and statistical modeling to quantify the spatial pattern of occurrence and risk during nesting and brood-rearing. We linked occurrence and risk models to provide spatially-explicit indices of habitat-performance relationships. As part of the analysis, we offer novel biological information on resource selection during egg-laying, incubation, and night. The spatial pattern of occurrence during all reproductive phases was driven largely by selection or avoidance of terrain features and vegetation, with little variation explained by anthropogenic features. Specifically, sage-grouse consistently avoided rough terrain, selected for moderate shrub cover at the patch level (within 90 m(2)), and selected for mesic habitat in mid and late brood-rearing phases. In contrast, risk of nest and brood failure was structured by proximity to anthropogenic features including natural gas wells and human-created mesic areas, as well as vegetation features such as shrub cover.Conclusions/Significance: Risk in this and perhaps other human-modified landscapes is a top-down (i.e., human-mediated) process that would most effectively be minimized by developing a better understanding of specific mechanisms (e.g., predator subsidization) driving observed patterns, and using habitat-performance indices such as those developed herein for spatially-explicit guidance of conservation intervention. Working under the hypothesis that industrial activity structures risk by enhancing predator abundance or effectiveness, we offer specific recommendations for maintaining high-performance habitat and reducing low-performance habitat, particularly relative to the nesting phase, by managing key high-risk anthropogenic features such as industrial infrastructure and water developments. AuthorsDzialak, Matthew R.; Olson, Chad V.; Harju, Seth M.; Webb, Stephen L.; Mudd, James P.; Winstead, Jeffrey B.; Hayden-Wing, L. D. Year Published2011 PublicationPLOS One LocationsDOI10.1371/journal.pone.0026273 |
| Experimental Chronic Noise Is Related to Elevated Fecal Corticosteroid Metabolites in Lekking Male Greater Sage-Grouse (Centrocercus urophasianus) | Blickley, Jessica L. | 2012 |
KeywordsNo keywords available AbstractThere is increasing evidence that individuals in many species avoid areas exposed to chronic anthropogenic noise, but the impact of noise on those who remain in these habitats is unclear. One potential impact is chronic physiological stress, which can affect disease resistance, survival and reproductive success. Previous studies have found evidence of elevated stress-related hormones (glucocorticoids) in wildlife exposed to human activities, but the impacts of noise alone are difficult to separate from confounding factors. Here we used an experimental playback study to isolate the impacts of noise from industrial activity (natural gas drilling and road noise) on glucocorticoid levels in greater sage-grouse (Centrocercus urophasianus), a species of conservation concern. We non-invasively measured immunoreactive corticosterone metabolites from fecal samples (FCMs) of males on both noise-treated and control leks (display grounds) in two breeding seasons. We found strong support for an impact of noise playback on stress levels, with 16.7% higher mean FCM levels in samples from noise leks compared with samples from paired control leks. Taken together with results from a previous study finding declines in male lek attendance in response to noise playbacks, these results suggest that chronic noise pollution can cause greater sage-grouse to avoid otherwise suitable habitat, and can cause elevated stress levels in the birds who remain in noisy areas. AuthorsBlickley, Jessica L.; Word, Karen R.; Krakauer, Alan H.; Phillips, Jennifer L.; Sells, Sarah N.; Taff, Conor C.; Wingfield, John C.; Patricelli, Gail L. Year Published2012 PublicationPLOS One LocationsDOI10.1371/journal.pone.0050462 |
| BIRDS OF A FEATHER DO NOT ALWAYS LEK TOGETHER: GENETIC DIVERSITY AND KINSHIP STRUCTURE OF GREATER SAGE-GROUSE (CENTROCERCUS UROPHASIANUS) IN ALBERTA | Bush, Krista L. | 2010 |
KeywordsCentrocercus urophasianus, dispersal, genetic diversity, Greater Sage-Grouse, kin selection, population genetics, relatedness AbstractAcr Endangered species are sensitive to the genetic effects of fragmentation, small population size, and inbreeding, so effective management requires a thorough understanding of their breeding systems and genetic diversity. The Greater Sage-Grouse (Centrocercus urophasianus) is a lekking species that has declined by 66-92% during the past 35 years in Alberta. Our goals were to assess the genetic diversity of Greater Sage-Grouse in Alberta and to determine the degree of sex-specific relatedness within and among leks. Six hundred and four individuals sampled in 1998-2007 were genotyped at 13 microsatellite loci. Levels of genetic diversity were high, with the exception of one recently founded lek, and did not change over time. Overall, we did not observe isolation-by-distance among leks, and most leks were not differentiated from one another, which suggests that gene flow occurs across the study area. Males and females exhibited similar patterns of isolation-by-distance, so dispersal was not sex-specific. Overall relatedness was close to zero for both sexes at the level of the province, lek, and year, which suggests that neither sex forms strong kin associations. However, we found relatedness within leks at the year level to be greater than zero, which indicates interannual variation. We also found no evidence that Greater Sage-Grouse follow the typical avian pattern of male philopatry. Although the species is endangered in Alberta and occurs in fragmented habitat, it has maintained genetic diversity and connectivity. Received 8 September 2008, accepted 22 September 2009. AuthorsBush, Krista L.; Aldridge, Cameron L.; Carpenter, Jennifer E.; Paszkowski, Cynthia A.; Boyce, Mark S.; Coltman, David W. Year Published2010 PublicationThe Auk: Ornithological Advances LocationsDOI10.1525/auk.2009.09035 |
| BALANCED SEX RATIO AT HATCH IN A GREATER SAGE-GROUSE (CENTROCERCUS UROPHASIANUS) POPULATION | Atamian, Michael T. | 2010 |
KeywordsCentrocercus urophasianus, CHD-gene, genetic sexing, Greater Sage-Grouse, parental investment, sex ratio. AbstractOnly one estimate of sex ratio at hatch exists for Greater Sage-Grouse (Centrocercus urophasianus). Managers typically assume a ratio at the population level of approximately 2:1 (female:male), primarily on the basis of sex ratio in the harvest. We determined the sex of newly hatched young and unhatched Greater Sage-Grouse by amplifying a portion of the sex-linked CHD gene. Sex ratio for Greater Sage-Grouse in east-central Nevada was 0.51 +/- 0.03 (SE; n = 272). We found no substantial difference in size between eggs that produced male chicks and those that produced females (44.5 + 0.2 mm(3) vs. 44.3 +/- 0.3 mm(3)) or between the masses of male and female chicks (25.8 +/- 0.3 g vs. 26.3 +/- 0.3 g), which suggests that energetic cost investments by females were similar between offspring of different sexes. We also found no effect of female condition oil differential investment in male versus female offspring. Given that adult survival does not differ Substantially between the sexes in our study Population (J. S. Sedinger unpubl. data), we suggest that this Population may not contain 2 adult females to I adult male and that any bias in adult sex ratio is likely attributable to differential survival from hatch to first breeding. Received 10 February 2009, accepted 1 june 2009. AuthorsAtamian, Michael T.; Sedingeir, James S. Year Published2010 PublicationThe Auk: Ornithological Advances LocationsDOI10.1525/auk.2009.09136 |
| GREATER SAGE-GROUSE (CENTROCERCUS UROPHASIANUS) SELECT NEST SITES AND BROOD SITES AWAY FROM AVIAN PREDATORS | Dinkins, Jonathan B. | 2012 |
Keywordsavian predator, brood-site selection, Centrocercus urophasianus, Greater Sage-Grouse, nest-site selection, predation risk, predator avoidance, spatial autocorrelation AbstractGreater Sage-Grouse (Centrocercus urophasianus) have declined in distribution and abundance in western North America over the past century. Depredation of nests and predation of chicks can be two of the most influential factors limiting their productivity. Prey species utilize antipredation behaviors, such as predator avoidance, to reduce the risk of predation. Birds in general balance the dual necessity of selecting cover to hide from visual and olfactory predators to enhance prospects of survival and reproductive success, which may also be achieved by selecting habitat with relatively fewer predators. We compared avian predator densities at Greater Sage-Grouse nests and brood locations with those at random locations within available sage-grouse habitat in Wyoming. This comparison allowed us to assess the species' ability to avoid avian predators during nesting and early brood rearing. During 2008-2010, we conducted 10-min point-count surveys at 218 nests, 249 brood locations from 83 broods, and 496 random locations. We found that random locations had higher densities of avian predators compared with nest and brood locations. Greater Sage-Grouse nested in areas where there were lower densities of Common Ravens (Corvus corax), Black-billed Magpies (Pica hudsonia), Golden Eagles (Aquila chrysaetos), and hawks (Buteo spp.) compared with random locations. Additionally, they selected brood-rearing locations with lower densities of those same avian predators and of American Kestrels (Falco sparverius), compared with random locations. By selecting nest and brood-rearing locations with lower avian predator densities, Greater Sage-Grouse may reduce the risk of nest depredation and predation on eggs, chicks, and hens. Received 24 May 2011, accepted 4 June 2012. AuthorsDinkins, Jonathan B.; Conover, Michael R.; Kirol, Christopher P.; Beck, Jeffrey L. Year Published2012 PublicationThe Auk: Ornithological Advances LocationsDOI10.1525/auk.2012.12009 |
| Parasites and Infectious Diseases of Greater Sage-Grouse. | Christiansen, Thomas J. | 2011 |
KeywordsCentrocercus urophasianus, disease, greater sage-grouse, parasite, pathogen AbstractWe report the parasites, infectious diseases, and noninfectious diseases related to toxicants found in Greater Sage-Grouse (Centrocercus urophasianus) across its range. Documentation of population-level effects is rare, although researchers have responded to the recent emergence of West Nile virus with rigorous efforts. West Nile virus shows greater virulence and potential population-level effects than any infectious agent detected in Greater Sage-Grouse to date. Research has demonstrated that (1) parasites and diseases can have population-level effects on grouse species; (2) new infectious diseases are emerging; and (3) habitat fragmentation is increasing the number of small, isolated populations of Greater Sage-Grouse. Natural resource management agencies need to develop additional research and systematic monitoring programs for evaluating the role of micro-and macro parasites, especially West Nile virus, infectious bronchitis and other corona viruses, avian retroviruses, Mycoplasma spp., and Eimeria spp. and associated enteric bacteria affecting sage-grouse populations. AuthorsChristiansen, Thomas J.; Tate, Cynthia M. Year Published2011 PublicationStudies in Avian Biology LocationsDOI10.1525/california/9780520267114.001.0001 |
| EFFECTS OF ENVIRONMENTAL FACTORS ON INCUBATION PATTERNS OF GREATER SAGE-GROUSE | Coates, Peter S. | 2008 |
KeywordsCentrocercus urophasianus, Common Raven, Greater Sage-Grouse, incubation, nest, predation, video. AbstractBirds in which only one sex incubates the eggs are often faced with a direct conflict between foraging to meet metabolic needs and incubation. Knowledge of environmental and ecological factors that shape life-history strategies of incubation is limited. We used continuous videography to make precise measurements of female Greater Sage-Grouse (Centrocercus urophasianus) incubation constancy (percentage of time spent at the nest in a 24-hour period) and recess duration. We used an information-theoretic approach to evaluate incubation patterns in relation to grouse age, timing of incubation, raven abundance, microhabitat, weather, and food availability. Overall, sage-grouse females showed an incubation constancy of 96% and a distinctive bimodal distribution of brief incubation recesses that peaked at sunset and 30 min prior to sunrise. Grouse typically returned to their nests during low light conditions. Incubation constancy of yearlings was lower than that of adults, particularly in the later stages of incubation. Yearlings spent more time away from nests later in the morning and earlier in the evening compared to adults. Video images revealed that nearly all predation events by Common Ravens (Corvus corax), the most frequently recorded predator at sage-grouse nests, took place during mornings and evenings after sunrise and before sunset, respectively. These were the times of the day when sage-grouse typically returned from incubation recesses. Recess duration was negatively related to raven abundance. We found evidence that incubation constancy increased with greater visual obstruction, usually from vegetation, of nests. An understanding of how incubation patterns relate to environmental factors will help managers make decisions aimed at increasing productivity through successful incubation. AuthorsCoates, Peter S.; Delehanty, David J. Year Published2008 PublicationThe Condor: Ornithological Applications LocationsDOI10.1525/cond.2008.8579 |
