Rates of Ovulation and Reproductive Success Estimated from Hunter-Harvested Greater Sage-Grouse in Colorado

Abstract Numerous studies provide estimates of nesting propensity rates (proportion of females attempting to nest at least once in a given year) for greater sage-grouse Centrocercus urophasianus. However, females may initiate nests without being detected during the course of normal research, leading to negatively biased estimates. We evaluated nesting propensity rates (rate of females laying ≥1 egg/y) by examining ovaries from 941 female sage-grouse collected at hunter-check stations in North Park, Colorado, during 1975–1984. Mean rate estimates of nesting propensity were lower for yearlings (0.926, 95% CI = 0.895–0.948) than adults (0.964, 95% CI = 0.945–0.978). We did not attempt to estimate laying rates (number of eggs laid per year) because they were likely unreliable. Nesting success—estimated as the probability of females producing a successful clutch in a given year based on primary feather replacement from hunter-harvested wings—was lower for yearlings (0.398, 95% CI = 0.370–0.427) than adults (0.571, 95% CI = 0.546–0.596). There were more chicks per female produced when nesting propensity rates were high, indicating nesting propensity rates correlate with the number of juveniles in the autumn population. Both nesting propensity rates and nesting success were positively related to precipitation during the lekking and brood-rearing seasons, respectively. Nesting propensity rates were positively related to spring abundance (as measured from annual lek counts), but nesting success was unrelated to spring abundance. A range-wide estimate of an unadjusted, apparent nesting propensity rate available from a previous study was approximately 7% lower than the North Park population. Postovulatory follicles provide a direct source of information on nesting propensity rates estimated from hunter-harvested sage-grouse. These estimated rates may prove useful to gain insights into annual variation of hunted populations' reproductive efforts.

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Sexual and subspecific variation in the numbers of rectrices of blue grouse

Canadian Journal of Zoology ◽

10.1139/z91-020 ◽

1991 ◽

Vol 69 (1) ◽

pp. 134-140 ◽

Cited By ~ 1

Author(s):

Fred C. Zwickel ◽

Mark A. Degner ◽

Donald T. McKinnon ◽

David A. Boag

Keyword(s):

Distinct Group ◽

Centrocercus Urophasianus ◽

Small Sample ◽

Hybrid Population ◽

Sage Grouse ◽

Modal Number ◽

The North ◽

Dendragapus Obscurus ◽

Coastal Birds ◽

Males And Females

We examined numbers of rectrices of all subspecies of blue grouse (Dendragapus obscurus), determined from our own studies and reported in the literature. Approximately 8% of all birds had an uneven number of rectrices, with no difference between males and females. More birds from a presumed subspecific "hybrid" population had uneven numbers of rectrices than those from "nonhybrid" samples. Of North American tetraonines, sage grouse (Centrocercus urophasianus) and blue grouse appear most variable in this character. Within subspecies, males and females had the same modal numbers of rectrices. The sexes differed, however, in the overall distribution of numbers of rectrices; most birds with submodal numbers were females and most birds with supermodal numbers, males. Males and females in one hybrid population differed in modal numbers of rectrices: males 20, and females 18. Eighty per cent of all coastal blue grouse had 18 rectrices, with no differences among subspecies. In contrast, all interior subspecies differed from each other. The two northern interior subspecies, D. o. pallidus and D. o. richardsonii, had modes of 20 rectrices, with that for pallidus weaker than that for richardsonii (70 and 81% modal, respectively). Dendragapus obscurus obscurus had a mode of 18 rectrices, not different from that for coastal birds. A small sample of D. o. oreinus was equally divided between birds with 18 and 20 rectrices, suggesting relationships with D. o. pallidus to the north and D. o. obscurus to the east. Northern interior blue grouse emerge as a distinct group with respect to modal number of rectrices, which parallels the pattern for the presence or absence of tail bands. Based on these two characteristics, coastal blue grouse appear more closely related to southern interior than to northern interior subspecies. The blue grouse is the only tetraonine with clear evidence of subspecific variation in numbers of rectrices.

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Sagebrush Soundscapes and the Effects of Gas-Field Sounds on Greater Sage-Grouse

Western Birds ◽

10.21199/wb52.1.2 ◽

2021 ◽

Vol 52 (1) ◽

pp. 23-46

Author(s):

Skip Ambrose ◽

Christine Florian ◽

Justin Olnes ◽

John MacDonald ◽

Therese Hartman

Keyword(s):

Background Level ◽

Centrocercus Urophasianus ◽

Sound Level ◽

Current Policy ◽

Sage Grouse ◽

Potential Threat ◽

Gas Field ◽

Brood Rearing ◽

Acoustic Data ◽

Sound Levels

Greater Sage-Grouse (Centrocercus urophasianus) use elaborate acoustic and visual displays to attract and select mates, and females and chicks depend on acoustic communication during brood rearing. A potential threat to the grouse is sounds associated with human activity. During April, 2013–2020, we collected 17,825 hours of acoustic data in three different acoustic situations in the sagebrush of Wyoming: rural, undeveloped areas (6), at Greater Sage-Grouse leks in a natural-gas field (20), and near active machinery in that gas field (17). The average existing sound levels in undeveloped sagebrush areas were LAeq = 26 dB and LA50 = 20 dB, and the average background sound level was LA90 = 14 dB. These values are lower than previously reported, due in part to our use of more sensitive equipment as well as addressing the influence of the instruments’ electronic self-noise. LAeq and LA50 at leks in the gas field ranged from 25.5 to 33.7 dB and 20.5 to 31.3 dB, respectively, depending on the distance, number, and type of nearby activities. Sound levels at leks were correlated with trends in the number of grouse using the lek: the higher the sound level, the greater the likelihood of a decline. Thresholds above which declines occurred were LAeq = 31 dB and LA50 = 26 dB. Leks with LAeq > 31 dB and LA50 >26 dB, 100% and 91%, respectively, had declining trends. Our findings suggest that the current policy of limiting sound levels at leks to LA50 < 10 dB (or LAeq < 15 dB) over the background sound level is appropriate, if an accurate background level is used.

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Nesting and Reproductive Activities of Greater Sage-Grouse in a Declining Northern Fringe Population

The Condor ◽

10.1093/condor/103.3.537 ◽

2001 ◽

Vol 103 (3) ◽

pp. 537-543 ◽

Cited By ~ 4

Author(s):

Cameron L. Aldridge ◽

R. Mark Brigham

Keyword(s):

Reproductive Effort ◽

Radio Telemetry ◽

Population Decline ◽

Centrocercus Urophasianus ◽

Chick Survival ◽

Sage Grouse ◽

Brood Rearing ◽

Northern Edge ◽

Northern Fringe ◽

Reproductive Activities

Abstract In Canada, Greater Sage-Grouse (Centrocercus urophasianus) are at the northern edge of their range, occurring only in southeastern Alberta and southwestern Saskatchewan. The population in Canada has declined by 66% to 92% over the last 30 years. We used radio-telemetry to follow 20 female Greater Sage-Grouse and monitor productivity in southeastern Alberta, and to assess habitat use at nesting and brood-rearing locations. All females attempted to nest. Mean clutch size (7.8 eggs per nest) was at the high end of the normal range for sage-grouse (typically 6.6–8.2). Nest success (46%) and breeding success (55%) were within the range found for more southerly populations (15% to 86% and 15% to 70%, respectively). Thirty-six percent of unsuccessful females attempted to renest. Fledging success was slightly lower than reported in other studies. Thus, reproductive effort does not appear to be related to the population decline. However, chick survival to ≥50 days of age (mean = 18%) was only about half of that estimated (35%) for a stable or slightly declining population, suggesting that chick survival may be the most important factor reducing overall reproductive success and contributing to the decline of Greater Sage-Grouse in Canada. Actividades de Anidación y Reproducción de Centrocercus urophasianus en una Población del Extremo Norte en Declive Resumen. En Canadá, Centrocercus urophasianus está en el extremo norte de su distribución, encontrándose sólo en el sureste de Alberta y el suroeste de Saskatchewan. La población de Canadá ha disminuido entre el 66% y 92% durante los últimos 30 años. Utilizamos radio-telemetría para seguir a 20 hembras de C. urophasianus y monitorear su productividad en el sureste de Alberta y para evaluar el uso de hábitat en sitios de anidación y de cría de los pichones. Todas las hembras intentaron anidar. El tamaño promedio de la nidada (7.8 huevos por nido) estuvo en el extremo superior del rango normal de C. urophasianus (típicamente 6.6–8.2). El éxito de anidación (46%) y de reproducción (55%) estuvieron dentro de los rangos encontrados en poblaciones de más al sur (15% a 86% y 15% a 70%, respectivamente). El treinta y seis por ciento de las hembras que no tuvieron éxito intentaron volver a anidar. El éxito en la crianza de polluelos hasta la etapa de volantones fue ligeramente menor que el reportado en otros estudios. Por lo tanto, el esfuerzo reproductivo no parece estar relacionado con el declive poblacional. Sin embargo, la supervivencia de los polluelos hasta 50 días de edad o más (promedio = 18%) fue sólo aproximadamente la mitad de lo que se ha estimado para una población estable o en ligero declive (35%), lo que sugiere que la supervivencia de los pichones podría ser el factor más importante reduciendo el éxito reproductivo en general y contribuyendo al declive de C. urophasianus en Canadá.

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A Meta-analysis of Greater Sage-grouse Centrocercus urophasianus Nesting and Brood-rearing Habitats

Wildlife Biology ◽

10.2981/0909-6396(2007)13[42:amogsc]2.0.co;2 ◽

2007 ◽

Vol 13 (sp1) ◽

pp. 42-50 ◽

Cited By ~ 61

Author(s):

Christian A. Hagen ◽

John W. Connelly ◽

Michael A. Schroeder

Keyword(s):

Meta Analysis ◽

Centrocercus Urophasianus ◽

Sage Grouse ◽

Brood Rearing

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Greater sage-grouse (Centrocercus urophasianus) nesting and brood-rearing microhabitat in Nevada and California—Spatial variation in selection and survival patterns

Open-File Report ◽

10.3133/ofr20171087 ◽

2017 ◽

Cited By ~ 4

Author(s):

Peter S. Coates ◽

Brianne E. Brussee ◽

Mark A. Ricca ◽

Jonathan E. Dudko ◽

Brian G. Prochazka ◽

...

Keyword(s):

Spatial Variation ◽

Centrocercus Urophasianus ◽

Sage Grouse ◽

Brood Rearing ◽

Survival Patterns

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Direct Identification of Northern Sage-grouse, Centrocercus urophasianus, Nest Predators Using Remote Sensing Cameras

The Canadian Field-Naturalist ◽

10.22621/cfn.v117i2.804 ◽

2003 ◽

Vol 117 (2) ◽

pp. 308 ◽

Cited By ~ 10

Author(s):

Matthew J. Holloran ◽

Stanley H. Anderson

Keyword(s):

Centrocercus Urophasianus ◽

Nesting Success ◽

Ground Squirrels ◽

Population Declines ◽

Sage Grouse ◽

Direct Identification ◽

Taxidea Taxus ◽

The Status ◽

Visual Confirmation ◽

Nest Predators

The status and apparent decline of Sage-grouse (Centrocercus spp.) has been of increasing concern and lower nesting success could be contributing to population declines. Our objective was to directly identify Sage-grouse nest predators. Following visual confirmation of radio-marked Sage-grouse nest establishment in 1997-1999, we installed automatic 35 mm cameras controlled by an active infrared monitor. Of 26 nests monitored by cameras, 22 successfully hatched and four were unsuccessful. American Elk (Cervus canadensis), Badger (Taxidea taxus), and Black-billed Magpie (Pica hudsonia) destroyed three of the four unsuccessful nests, and domestic cattle caused abandonment of the fourth. Richardson’s (Spermophilus richardsonii) and Thirteen-lined Ground Squirrels (S. tridecemlineatus) were recorded at nests, but were not detected in predation.

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Field guide to Laramide basin evolution and drilling activity in North Park and Middle Park, Colorado

The Mountain Geologist ◽

10.31582/rmag.mg.53.4.283 ◽

2016 ◽

Vol 53 (4) ◽

pp. 283-329

Author(s):

Marieke Dechesne ◽

Jim Cole ◽

Christopher Martin

Keyword(s):

Oil And Gas ◽

Front Range ◽

Geologic Mapping ◽

The West ◽

Field Guide ◽

Coal Resources ◽

The North ◽

Continental Divide ◽

North Park ◽

Park Area

This two-day field trip provides an overview of the geologic history of the North Park–Middle Park area and its past and recent drilling activity. Stops highlight basin formation and the consequences of geologic configuration on oil and gas plays and development. The trip focuses on work from ongoing U.S. Geological Survey research in this area (currently part of the Cenozoic Landscape Evolution of the Southern Rocky Mountains Project funded by the National Cooperative Geologic Mapping Program). Surface mapping is integrated with perspective from petroleum exploration within the basin. The starting point is the west flank of the Denver Basin to compare and contrast the latest Cretaceous through Eocene basin fill on both flanks of the Front Range. The next stop continues on the south end of the North Park–Middle Park area, about 60 miles [95km] west from the first stop. A general clockwise loop is described by following U.S. Highway 40 from Frasier via Granby and Kremmling to Muddy Pass after which CO Highway 14 is followed to Walden for an overnight stay. On the second day after a loop north of Walden, the Continental Divide is crossed at Willow Creek Pass for a return to Granby via Highway 125. The single structural basin that underlies both physiographic depressions of North Park and Middle Park originated during the latest Cretaceous to Eocene Laramide orogeny (Tweto, 1957, 1975; Dickinson et al., 1988). It largely filled with Paleocene to Eocene sediments and is bordered on the east by the Front Range, on the west by the Park Range and Gore Range, on the north by Independence Mountain and to the south by the Williams Fork and Vasquez Mountains (Figure 1). This larger Paleocene-Eocene structural basin is continuous underneath the Continental Divide, which dissects the basin in two approximately equal physiographic depressions, the ‘Parks.’ Therefore Cole et al. (2010) proposed the name ‘Colorado Headwaters Basin’ or ‘CHB,’ rather than North Park–Middle Park basin (Tweto 1957), to eliminate any confusion between the underlying larger Paleocene-Eocene basin and the two younger depressions that developed after the middle Oligocene. The name was derived from the headwaters of the Colorado, North Platte, Laramie, Cache La Poudre, and Big Thompson Rivers which are all within or near the study area. In this field guide, we will use the name Colorado Headwaters Basin (CHB) over North Park–Middle Park basin. Several workers have described the geology in the basin starting with reports from Marvine who was part of the Hayden Survey and wrote about Middle Park in 1874, Hague and Emmons reported on North Park as part of the King Survey in 1877, Cross on Middle Park (1892), and Beekly surveyed the coal resources of North Park in 1915. Further reconnaissance geologic mapping was performed by Hail (1965 and 1968) and Kinney (1970) in the North Park area and by Izett (1968, 1975), and Izett and Barclay (1973) in Middle Park. Most research has focused on coal resources (Madden, 1977; Stands, 1992; Roberts and Rossi, 1999), and oil and gas potential (1957, all papers in the RMAG guidebook to North Park; subsurface structural geologic analysis of both Middle Park and North Park (the CHB) by oil and gas geologist Wellborn (1977a)). A more comprehensive overview of all previous geologic research in the basin can be found in Cole et al. (2010). Oil and gas exploration started in 1925 when Continental Oil's Sherman A-1 was drilled in the McCallum field in the northeast part of the CHB. It produced mostly CO2 from the Dakota Sandstone and was dubbed the ‘Snow cone’ well. Later wells were more successful finding oil and/or gas, and exploration and production in the area is ongoing, most notably in the unconventional Niobrara play in the Coalmont-Hebron area.

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