Kerry P. Reese

Long-term effects of fire on sage grouse habitat.

This study documented the long-term (> 10 years) impact of fire on sage grouse (Centrocercus urophasianus Bonaparte) nesting and brood-rearing habitats on the Upper Snake River Plain in southeastern Idaho. The habitat of the study area is primarily mountain big sagebrush (Artemisia tridentata vaseyana Rydb.)grassland. Twenty different-aged burns were sampled from 1996 to 1997, ranging from wildfires which burned during the 1960s to prescribed fires set during the 1990s. Canopy coverage and height of vegetation, and relative abundance of invertebrates, were estimated at burned and unburned sites within burns. Fourteen years after burning, sagebrush had not returned to preburn conditions. No difference was detected in forb abundance between different-aged burns. Relative abundance of ants and beetles was significantly greater in the 1-year old burn category but had returned to unburned levels by 3-5 years postburn. No benefits for sage grouse occurred as a result of burning sage grouse nesting and brood-rearing habitats. Burning created a long-term negative impact on nesting habitat because sagebrush required over 20 years of postburn growth for percent canopy cover to become sufficient for nesting.

An investigation on fire effects within xeric sage grouse brood habitat

We investigated the short-term influence of fire on xeric sage grouse (Centrocercus urophasianus) brood habitat in southeastern Idaho from 1990-92. A prescribed fire in 1989 removed Wyoming big sagebrush (Artemisia tridentata wyomingensis Nutt.)/threetip sagebrush (A. tripartita Rydb.) canopy cover from approximately 57% of a 5,800-ha area, potentially influencing brood-rearing habitat. Although the fire created a mosaic of sagebrush areas interspersed with open areas having abundant grasses and forbs, the relative abundance of males, females, and broods on survey routes in burned and unburned habitat were similar. Cover of forbs important in sage grouse summer diets was similar in burned and unburned habitat. However, the abundance of Hymenoptera, an insect Order important in sage grouse diets, was significantly lower in burned habitat the second and third years postburn. Our research did not support the contention that fire may enhance sage grouse brood-rearing habitat.

Sage grouse use of nest sites in southeastern Idaho

We investigated nest site selection by sage grouse (Centrocercus urophasianus) in southeastern Idaho from 1987 to 1989. During 3 breeding seasons, 79% of 84 nest sites were found under sagebrush (Artemisia spp.). Nest success averaged 53% for grouse that used sagebrush and 22% for birds that used nonsagebrush nest sites. Total vegetative cover for sagebrush and nonsagebrush nest sites was similar. However, grass height was shorter (P = 0.01) at sagebrush compared to nonsagebrush nest sites. Herbaceous cover was important to nesting sage grouse but the relatively low nest success of nonsagebrush nest sites indicated they might provide less than optimal nesting habitat. J. WILDL. MANAGE. 55(3):521-524 Most studies that have examined sage grouse nest site selection reported that >90% of nests were found under sagebrush (Patterson 1952: 114, Gill 1965, Wallestad and Pyrah 1974, Braun et al. 1977, Gates 1983). Other species of shrubs commonly grow in sagebrush habitats (Tisdale and Hironaka 1981) but are seldom used by nesting sage grouse. Only Hulet et al. (1984) reported a relatively high incidence (34%) of sage grouse use of shrubs other than sagebrush (hereafter called nest shrub species) for nest sites. Unfortunately, Hulet et al. (1984) did not address the relationship of nest shrub species to habitat quality and nesting success. Our purpose is to describe the use of nest shrub species by sage grouse in southeastern Idaho and to test the hypothesis that nesting success for grouse nesting under sagebrush is greater than that of grouse nesting under other plant species. We thank E. F. Cassirer, J. F. Kennedy, R. R. Spahr, C. M. Stinson, and D. W. Stinson for aid in collecting nest data. We also acknowledge the support of the Bureau of Land Management, U.S. Forest Service, and Idaho Department of Fish and Game. This manuscript was improved by reviews provided by J. J. Beecham, C. E. Braun, J. A. Crawford, R. L. Eng, T. P. Hemker, J. W. Hupp, T. E. Remington, and an anonymous referee. This paper is a contribution from Idaho Federal Aid in Wildlife Restoration Project W-160-R and contribution No. 560 of the Idaho Forest, Wildlife, and Range Experiment Station.

Movements and Survival of Juvenile Greater Sage‐Grouse in Southeastern Idaho

Abstract Low recruitment has been suggested as a primary factor contributing to declines in greater sage-grouse (Centrocercus urophasianus) populations. We evaluated movements and survival of 58 radiomarked juvenile greater sage-grouse from 1 September (≥10 weeks of age) to 29 March (≥40 weeks of age) during 1997–1998 and 1998–1999 in lowland and mountain valley study areas in southeastern Idaho, USA. Juvenile sage-grouse captured in the mountain valley area moved an average of 2.2 km (20%) farther (x̄ = 13.0 km, SE = 1.2 km) from autumn to winter ranges than juvenile grouse captured in the lowland area (x̄ = 10.8 km, SE = 1.2 km). Ten of 11 deaths occurred from September to December. Fifty percent of deaths in the lowland population were attributable to human-related mortality including power-line collisions and legal harvest, while 33% and 17% of deaths were attributable to mammalian predators and unknown cause, respectively. All deaths in the mountain valley population were attributed to avian or mammalian predators. Survival was relatively high for birds from both populations, but was higher across years in the lowland (Ŝ = 0.86, SE = 0.06, n = 43) than in the mountain valley population (Ŝ = 0.64, SE = 0.13, n = 14). In our study juvenile sage-grouse that moved farther distances to seasonal ranges experienced lower survival than juveniles from a more sedentary population. Moreover, high juvenile survival in our study suggests that if low recruitment occurs in sage-grouse populations it may be due to other factors, especially poor nesting success or low early chick survival.

Movements, survival, and reproduction of sage grouse translocated into central Idaho

The success of translocations to restore sage grouse (Centrocercus urophasianus) populations remains equivocal. Thus, we translocated 196 sage grouse to the Sawtooth Valley, Idaho, during March-April 1986-87 to determine whether translocated birds would survive and reproduce. Movements of 44 radio-tagged birds were extensive during the first 3-6 weeks post-release, and average distances from the release site for 10 females (5.3 ± 0.9 km) were greater (P < 0.05) than those for 5 males (3.2 ± 1.0 km). Four of 17 (24%) radio-tagged birds in 1986 and 11 of 27 (41%) in 1987 survived into the summer

Sage grouse nest locations in relation to leks

We tested 2 predictions about the locations of nets of lek-forming species to evaluate a guideline developed to protect sage grouse (Centrocercus urophasianus) nesting habitat. Sage grouse (n=37) in southeastern Idaho did not attempt to nest midway between leks, as 1 hypothesis suggests. Neither was there evidence indicating that areas surrounding a lek are important for nesting, as a second hypothesis suggests. Because distribution of sage grouse nests was random with respect to lek location, nesting habitat protection based on either hypothesis affords no special protection for nests

Distribution, movements and habitats of sage grouse Centrocercus urophasianus on the Upper Snake river plain of Idaho: changes from the 1950s to the 1990s.

The sage grouse Centrocercus urophasianus population level on the Upper Snake River Plain of Idaho has declined significantly over the past 40 years. We investigated migration patterns and seasonal ranges of these birds to compare to patterns from the 1950s and 1960s. Furthermore, we examined landscape changes that occurred between 1975 and 1992. Migration patterns have not changed since the 1950s. The grouse currently migrate up to 125 km and use an annual population range of at least 2,764 km2. The major landscape change since 1975 that occurred in sage grouse habitat was a decline in the total amount of winter range. Between 1975 and 1992,29,762 ha of sagebrush Artemisia spp. rangeland were converted to cropland, a 74% increase in cropland. Regression analysis suggested a relationship between sagebrush habitat loss and grouse population decline (R2 = 0.59, P = 0.002). Approximately 1,244 km2 of privately-owned sagebrush on the study area could potentially be converted to cropland, which we predict would have serious negative implications for the sage grouse population.

Effects of Predation and Hunting on Adult Sage Grouse Centrocercus urophasianus in Idaho

Although sage grouse Centrocercus urophasianus have declined throughout their range in North America, little is known about annual mortality patterns of this species. Thus, we summarize a long-term data set on timing and causes of mortality of sage grouse. Predation was the most common cause of death for radio-marked sage grouse. For adult males, 83% of deaths were attributed to predation and 15% to hunting. However, for adult females, 52% of deaths were caused by predation while 42% were attributed to hunting. We rejected the hypothesis that type of mortality (predation vs hunting) was independent of gender of sage grouse. For males, 70% of deaths occurred during spring and summer (March-August) and 28% occurred in September-October. For females, 52% of mortalities occurred during spring and summer and 46% occurred in September-October. We rejected the hypothesis that time of death is independent of the gender of sage grouse. In six of 15 years (40%), harvest rates for adult females may have exceeded 10% while this rate was only exceeded in two of 15 years (13%) for adult males.

Renesting by sage grouse in Southeastern Idaho

Renesting in Tetraonidae has been investigated in a number of studies (e.g., Patterson 1952, Zwickel and Lance 1965, Giesen and Braun 1979, Parker 1981, Bergerud 1988, Bergerud and Gratson 1988). Unfortunately, information on renesting by Sage Grouse (Centrocercus urophasianus) is limited and highly variable. Both Patterson (1952:105) and Eng (1963) reported that renesting by Sage Grouse is relatively rare (<10%). However, Bergerud (1988) suggested that renesting rates by this species exceed 40%, based on a synthesis of the literature and Petersens (1980) report that 7 of 17 (41%) radio-marked Sage Grouse renested. The relative vulnerability of nests and life expectancy of the female may strongly influence renesting rates in grouse (Bergerud and Gratson 1988). Bergerud and Gratson (1988) argued that if predators are active near a Sage Grouse nest, the probability of nest loss is high because of relatively sparse cover. Thus, nest abandonment and renesting would be an advantageous strategy for this species. However, grouse with long life expectancies should renest less often than shorter lived species (Bergerud and Gratson 1988) and yearlings should renest less often than adults (Bergerud 1988). Sage Grouse have relatively long lives (Patterson 1952, Bergerud 1988) which, therefore, should result in lower renesting rates than other grouse species. The objectives of this study are to document renesting rates by Sage Grouse in Idaho and to test the hypotheses that yearling and adult Sage Grouse nest and renest at the same rates.

Response of greater sage-grouse Centrocercus urophasianus populations to different levels of exploitation in Idaho, USA

We investigated the response of greater sage-grouse Centrocercus urophasianus populations to different levels of exploitation. From 1995 through 2002 we monitored breeding populations in areas closed to hunting, open to limited hunting (1-bird daily bag limit; 7-day season), and open to moderate hunting (2-bird daily bag limit; 23-day season). We used three approaches to assess the effects of hunting on sage-grouse populations. Results were consistent regardless of the method used and indicated that overall, areas closed to hunting had greater rates of increase for breeding populations than areas open to hunting (P = 0.018). Limited or moderate rates of exploitation apparently slowed population recovery for sage-grouse. These effects may have been more pronounced for grouse occupying relatively xeric habitats close to human population centers or highly fragmented habitats. Our results suggest that hunting seasons for sage-grouse should generally be conservative and reflect both sage-grouse population trend and quality of habitat occupied by the population.