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This paper provides an overview of conservation status and major threats to grouse based on information collected by the IUCN/SSC BirdLife WPA Grouse Specialist Group during 2004-2005. At the time of compiling the first Grouse Action Plan (Storch 2000b) in 1999, no grouse species were considered to be threatened following the IUCN criteria, but three species with limited geographic distribution were listed as Near Threatened (IUCN 1996): Caucasian black grouse Tetrao mlokosiewiczi, Chinese grouse Bonasa sewerzowi, and Siberian grouse Dendragapus falcipennis. In 2000, the newly recognised Gunnison sage-grouse Centrocercus minimus was listed as Endangered and the Caucasian black grouse was reclassified to Data Deficient. Shortly after, both the lesser prairie-chicken Tympanuchus pallidinctus and the greater prairie-chicken T. cupido were added to the Red List as Vulnerable owing to rapid population declines, and the greater sage-grouse Centrocercus urophasianus was listed as Near Threatened (IUCN 2004). At a national level, 14 of the 18 known grouse species are red-listed in at least one country. Populations at the southern edge of a species' range and in densely populated regions are most often red-listed. Based on questionnaire responses from 47 countries, habitat degradation, loss and fragmentation due to human land use activities are the major threats to grouse viability. Exploitation, predation, human disturbance and climate change were regionally believed to be critical. Integrating habitat preservation and human land use practices is concluded to be the major challenge to grouse conservationists worldwide.
We conducted spring and autumn surveys of Caucasian black grouse Tetrao mlokosiewiczi throughout northeastern Turkey during 2004-2005. Birds were found at 45 locations, 29 of which were previously undocumented. The species appears to occur in four geographical units with differing degrees of connectivity and isolation, and is still under pressure from illegal hunting as well as habitat deterioration and fragmentation, principally as the result of road construction in mountain areas. A preliminary analysis of the degree of overlap between grouse populations and protected areas shows that the protected areas network should be reviewed. The data collected during the course of this survey are being used to develop a model for predicting the distribution of black grouse in northeastern Turkey and to prepare a National Species Action Plan. A detailed ecological study of the Caucasian black grouse is required to develop habitat management recommendations for the species.
Most habitat models developed for defining priority conservation sites target areas currently exhibiting suitable habitat conditions. For species whose habitats have been altered by land use practices, these models may fail to identify sites with the potential of producing suitable habitats, if management practices were modified. Using capercaillie Tetrao urogallus as an example, we propose a model for evaluating the potential of ecological conditions at the landscape level to provide suitable habitat at the local scale. Initially, we evaluated the influence of selected landscape parameters on the structural characteristics of vegetation relevant to capercaillie. Then we used capercaillie presence data and an ecological niche factor analysis (ENFA) to identify landscape and land use variables relevant to capercaillie habitat selection. We also studied the effect of scale on predictive model quality. Despite high variance, correlations between landscape variables and forest structure were detected. The greatest influence on forest structure was recorded for climate and soil conditions, which were also found to be the best predictors of capercaillie habitat selection in the ENFA. The final model, retaining only two landscape variables (soil conditions and days with snow) and three land use variables (proportion of forest, distance to roads and forest-agricultural borders), explained a high degree of capercaillie habitat selection, even before considering patch size and connectivity. By restricting the analyses to areas with stable subpopulations and a set of relatively stable landscape variables capable of explaining habitat quality at a local scale, we were able to identify areas with long-term relevance to conservation of capercaillie.
We conducted this 2-year study to determine if lesser prairie-chickens Tympanuchus pallidicinctus and ring-necked pheasants Phasianus colchicus used the same habitats where their ranges overlapped in southwestern Kansas. Telemetry locations of 50 transmitter-equipped lesser prairie-chickens and 28 pheasants were used to monitor habitat use by the two species. Additionally, vegetation characteristics at 39 nest sites of lesser prairie-chickens were compared to those at 14 pheasant nest sites. Morisita's Index of niche overlap detected moderate similarities of habitat mixes used by lesser prairie-chickens and pheasants, but location data showed that spatial use of those habitats differed. Vegetation structure around nest sites of the two species differed significantly indicating selection of different habitat for nesting birds, and lesser prairie-chickens nested far from the outer edges of native prairie whereas pheasants nested nearer the outer edges. Despite the modest amount of similarity in mixes of habitats used by lesser prairie-chickens and ring-necked pheasants, we conclude that the two species occupy separate niches given the current extent of habitat in southwestern Kansas. However, if additional habitat loss or fragmentation occurs pheasants may gain competitive advantage over lesser prairie-chickens. Thus, we recommend maintaining and conserving large blocks of native habitat as well as the connectivity between them as a management strategy for maintaining populations of lesser prairie-chickens.
The distribution and range of the greater sage-grouse Centrocercus urophasianus have been reduced by 56% since the European settlement of western North America. Although there is an unprecedented effort to conserve the species, there is still considerable debate about the vegetation composition and structure required for nesting and brood-rearing habitat. We conducted a meta-analysis of vegetation characteristics recorded in studies at nest sites (N = 24) and brood habitats (N = 8) to determine if there was an overall effect (Hedge's d) of habitat selection and to estimate average canopy cover of sagebrush Artemisia spp., grass and forbs, and also height of grass at nest sites and brood-rearing areas. We estimated effect sizes from the difference between use (nests and brood areas) and random sampling points for each study, and derived an overall effect size across all studies. Sagebrush cover (d = 0.39; 95% C.I.: 0.19-0.54) and grass height (d = 0.28; 95% C.I.: 0.13-0.42) were greater at nest sites than at random locations. Vegetation at brood areas had less sagebrush cover (d = -0.17; 95% C.I.: -0.44 - 0.18), significantly taller grasses (d = 0.31; 95% C.I.: 0.14-0.45), greater forb (d = 0.48; 95% C.I.: 0.30-0.67) and grass cover (d = 0.17; 95% C.I.: 0.08-0.27) than at random locations. These patterns were especially evident when we examined early (< 6 weeks post hatching) and late brood-rearing habitats separately. The overall estimates of nest and brood area vegetation variables were consistent with those provided in published guidelines for the management of greater sage-grouse.
We quantified forest stand attributes at ruffed grouse Bonasa umbellus drumming display sites to develop tree stocking guides as a tool for guiding ruffed grouse management. We estimated tree density and basal area surrounding grouse drumming sites and compared these with unused sites. We used model selection to assess predictions about whether tree density and basal area surrounding drumming sites varied by site classification (primary drumming site, alternate site, unused site) or forest type. We plotted the predicted values from the best model on tree stocking guides, which are tools commonly used by forest managers. Tree density and basal area varied by site classification and by forest type. Our results show that stem density was higher and basal area lower at both primary and alternate drumming sites compared to unused sites in all forest types. We also found that grouse sites in aspen stands had a greater stem density and lower basal area than grouse sites in pine and spruce/fir stands. Incorporating these results into a tree stocking guide suggested that management for grouse in aspen stands should attempt to maintain stands with average stem density and basal area for this species. In contrast, foresters who are managing for conifers and also wish to maintain some grouse habitat should favour wider spacing of trees in stands. Wider spacing will encourage the development of dense understory vegetation favoured by grouse as well as enhance the growth of quality saw-logs. Our study describes a method for incorporating habitat data on ruffed grouse and other wildlife into tree stocking charts, which are commonly used to facilitate management of forest stands.
Capercaillie Tetrao urogallus leks have repeatedly been reported to be located in old forest. However, two conditions may have biased this widely held view. First, leks are known to be continuously used over several decades, and therefore might have been established when forest stands were younger. Second, stand-replacement logging (clearcutting) was not widely applied until the 1950s, leaving even-aged regenerating stands too young for leks to have been established in the latter part of the 20th century. Here we report eight cases of lek formation in young plantations from south-central Norway. Stand age ranged within 26-46 years when display activity started. At six of the sites, we confirmed that females were regularly feeding on pine trees in winter prior to lek establishment, and at four of these sites displaying males were observed courting the females in late winter. These findings support the hotspot model of lek formation put forward by Gjerde et al. (2000), and it offers promising options for managing capercaillie leks in commercially utilised forests.
During 1995-2004, we studied the nest site selection of the Chinese grouse Bonasa sewerzowi at Lianhuashan, Gansu, China. Of the 103 nests that we found, 56% were at the base of deciduous trees, mainly willow Salix spp. and birch Betula utilis, and 40% were at the base of coniferous trees. The Chinese grouse favoured northern and eastern slopes with steepness of 0-45°, averaging 15.5 ± 11.2° (SE; N = 97); 88% of nest sites were on slopes of < 30°. The average cover around the nest was 50.8 ± 20.3% (SE; N = 86). The degree to which the female was covered at successful nests was 51.4 ± 19.9% (SE; N = 45), which was not different from that of unsuccessful nests (43.1 ± 19.1% (SE); N = 17). Chinese grouse preferred to nest in coniferous and coniferous-deciduous mixed forests at sites with fewer trees and denser shrubs, compared with the available vegetation. Females nested on average 154.2 ± 109.0 m (SE; N = 19) from the previous year's nest. Compared with the hazel grouse B. bonasia, the Chinese grouse showed a greater preference for nesting at the base of trees or stems.
To survive in harsh winter conditions, animals must make behavioural and physiological adaptations. The selection of good habitats may prevent a negative energy budget and reduce predation risk. The capercaillie Tetrao urogallus, the largest of all grouse, feeds in winter on conifer needles, a superabundant but low-energy food resource. We hypothesised that capercaillie should select nocturnal roosting trees that simultaneously provide food, minimise predation risk and reduce energy expenditure. Using paired logistic regression, we studied night roost selection in winter in the Black Forest (Germany), the Swiss Jura, the Swiss Alps and the Thuringia Forest (Germany) by comparing 508 pairs of roosting trees and matched control trees. The most important factors discriminating roosting trees from random trees were tree species and number of forest aisles leading away from the roost tree. Trees with more than one nearby forest aisle for escape by flight were preferred over those with only one aisle or none. Capercaillie strongly selected pine trees Pinus spp for nocturnal roosting, and avoided Norway spruce Picea abies. At sites without pine trees, deciduous trees were preferred. Compared to females, males preferred larger trees in more open forest stands. Our results suggest that the selection of night roosts is determined by predator avoidance, energy-saving strategies aimed at reducing flight activity and feeding possibilities. Microclimate does not seem to influence selection of night roosts.
High mortality among chicks, due to fragmentation and changes in habitat caused by commercial forestry, is considered one of the main reasons for the general decline in capercaillie Tetrao urogallus in boreal forests. Using GPS satellite telemetry, we studied the movement patterns of young capercaillie broods: 1) to test if this new technology could be applied to gain more detailed insight into behaviour and habitat selection at a small spatial scale, and if so, 2) to compare the broods' relative use of planted and older, naturally regenerated forests. Hens of four broods with chicks 2-7 days old were captured and fitted with 90-g backpacks containing GPS units and VHF transmitters. The GPS units were programmed to record positions every 15 minutes, the shortest interval possible. With a storage capacity of 450 positions, movements could be monitored for ca 4.5 days. In our study area (Varaldskogen) with moderate topography, the GPS technology performed quite well. A total of 1,277 positions were obtained (84% of potential maximum), of which 77% were within 20 m of the true position of the brood. The movement patterns of the four broods were quite similar, with a mean speed of 83.2 m ± 9.9 (SE) per hour during the 4.5-day tracking period. Broods moved almost continuously during the 24-hour cycle, presumably foraging, although their speed was slower at night. The two oldest broods whose initial age was seven days moved faster than the two younger broods whose initial age was two and three days, respectively. Strong autocorrelation among successive positions made us examine habitat selection using a binominal choice method for each brood separately. When broods were inside old ‘natural’ forest, they remained there instead of moving into plantations. When inside plantations, they did not discriminate between remaining there and moving into nearby old forest, but they tended to move faster in plantations than in old forest. Clearly, the new, cost-effective GPS telemetry offers new and better opportunities for studying small-scale brood movement. Very frequent and accurate positions can be obtained without either disturbing the birds or leaving scent marks that may attract predators.
Life-history studies of prairie grouse have focused on reproductive ecology, habitat use, movement patterns and survivorship, with only cursory or anecdotal references to mortality causes, or they have been of insufficient duration or scale to infer mortality patterns. Because mortality causes and patterns affect other life-history traits, their determination adds to our overall understanding of grouse demographics. As part of a long-term study on lesser prairie-chicken Tympanuchus pallidicinctus natural history in Oklahoma and New Mexico, we recovered 322 carcasses of radio-tagged birds captured on leks. We were able to determine the cause of death for 260 of these birds. Predation by raptors accounted for the largest number of mortalities (91), followed by collisions with fences (86), predation by mammals (76), collisions with power lines (4), and collisions with automobiles (3). Mortality causes differed considerably between study sites and between sexes, with all collisions more frequent in Oklahoma than in New Mexico, in females than in males, and in older than in young females. Although predation is a major cause of mortality, we argue that predator control may not be effective for grouse conservation. Moreover, in cases where top predators reduce mesopredator population densities, for example those of red foxes Vulpes vulpes, indiscriminate removal of predators may hasten the decline of grouse populations. Land managers striving to conserve prairie-chickens and other grouse species should attempt to reduce or eliminate collision mortality risks in addition to efforts to improve nesting or brood-rearing habitat. Collision risks should also be evaluated for potential release sites of translocated or captive-reared grouse.
The only long-term census of hazel grouse Bonasa bonasia in Central Europe was conducted during 1972-2004 on a 100-km2 area of the Bohemian Forest, Šumava, Czech Republic. To obtain a density index in October, I recorded indirect signs of hazel grouse, such as dust bathing sites, feathers, droppings or tracks, and reactions to a whistle that imitates the male territorial song along fixed routes covering 80 km in total. During the 33 years of counting, I found no statistically significant trend in the fluctuating numbers. I also looked for the influence of weather on hazel grouse abundance. Analysis by stepwise multiple regression suggested that six weather variables were correlated with the annual rate of change of hazel grouse density in autumn, explaining 44% of the variation in density: mean temperature and total precipitation in April (highly significant positive correlations) and mean temperature and total precipitation in May and September (significant negative correlations). The results for April and May seem to indicate a positive effect of rainfall and temperature in April on reproductive success in the pre-laying period, but a negative effect of rainfall in May on chick survival.
In the United Kingdom, black grouse Tetrao tetrix are in severe decline with only 6,500 displaying males in 1995-1996 and a range retraction of 28% between 1972 and 1991. Recent declines have been greatest in central and southern Scotland and parts of Wales and contrast with relative stability in northern England. We compare the demography of black grouse in three regions: North Wales, northern England and the Scottish Highlands. Patterns in annual fecundity, measured as fledglings per breeding female, were correlated between regions, suggesting that annual weather patterns common across regions may be a key determinant of breeding success. Site related effects such as habitat quality or management were also significant in northern England and North Wales. Male population growth rates at leks were positively correlated with fecundity in the previous year. Fecundity was highest in North Wales and the Scottish Highlands at 1.7 chicks per female in August compared to 1.3 in northern England. Variations in the annual fecundity of radio-tagged females were linked to differences in brood survival rather than clutch survival, which did not differ among years. We found a non-significant trend for juvenile survival to be lower in North Wales (0.18) than in either northern England (0.65) or the Scottish Highlands (0.56). Similarly, annual adult survival also tended to be lower in North Wales (0.44) than in either northern England (0.70) or the Scottish Highlands (0.66). Predation was the main cause of death in all regions, with red fox Vulpes vulpes and raptors being the chief predators in North Wales and the Scottish Highlands and stoat Mustela erminea in northern England. The last 10 years have seen the implementation of a series of black grouse recovery projects in the UK. An understanding of the limiting demographic stage in each project area is critical before appropriate remedial management prescriptions can be implemented.
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