Long-term emissions of calcium-containing dusts from an iron factory influenced soil pH, vegetation and perhaps contributed to the capercaillie Tetrao urogallus decline in the study area in eastern Germany. Dramatic changes of the ground vegetation were observed in time (vegetation analyses in 1956, 1965, 1983 and 1990–1993) and along the pH-gradient. Near the emission source the mean number of plant species has increased from 15 to 65 since 1956. Ericaceae (Vaccinium myrtillus, V. vitis-idea, Calluna vulgaris), which are essential to capercaillie for food and cover, were replaced by Senecio fuchsii, Digitalis purpurea, Dactylis glomerata, Calamagrostis epigeios, Rubus idea, Myringia trinerva, and Urtica dioica. The decline in capercaillie numbers was correlated with the eutrophication effects of the emissions as measured by the increase of plant species diversity. Increasing plant species diversity may also favour small rodents and thereby the density of predators (such as the red fox Vulpes vulpes and wild boar Sus scrofa), as indicated by the increased hunting bags. Therefore, the increased predation on capercaillie nests and chicks that was documented on the study area over time may be a secondary effect of air-borne pollution.

In the French Pyrenees, lek habitats of capercaillie Tetrao urogallus are spatially separated from brood-rearing habitats, which are defended by hens before laying. Spring territories of hens thus determine the placement of leks, which are as near to the geometric centre of the locations of one or more territorial hens as lek habitat allows. The number of cocks on leks on a small and large study area was proportional to the number of territorial hens. Locations of leks were systematically influenced by proximity of brood habitats, and the number of cocks on leks was positively correlated with the total area of brood habitats. Establishment of a lek may depend on the prior presence of one or more territorial hens. Because hens influence establishment and size of leks, territoriality in hens may limit numbers of both cocks and hens. These findings support recent models emphasising the effects of hens on lek formation, and contrast with those from Norway, where behaviour and habitat requirements of cocks determine size and location of leks. This may result from brood habitats in the Pyrenees being in localised patches, whereas those in Norway are available throughout the forest. However, the regular distribution pattern of leks in both the Pyrenees and Norway, supports the aspect of the Norwegian model which attributes lek location to the spacing behaviour of cocks.

This paper compares spacing behaviour of male and female capercaillie Tetrao urogallus in the German Alps, to those reported from the boreal zone, and discusses their implications for models of lek evolution. Based on 23 males and 13 females radio-tracked during April-May 1988–1992, the size, arrangement, and overlap of home ranges of males, and home ranges, lek visitation, and location of nest sites of females are described in relation to habitat, lek location, and the birds' age. Independently of sex and age, capercaillie preferred old forest habitats. With the exception of juveniles and some subadults that used large home ranges and visited several leks, males occupied permanent but overlapping territories clumped within 1 km of lek centres. Territorial traits were most pronounced in the oldest, dominant males: they used the smallest territories closest to the lek centre, used the central parts of their territories exclusively and showed the strongest site tenacity; nevertheless they tolerated subordinates within their territories. Females stayed farther from leks than males, most visited several leks, and nested at random distances from leks. Independently of habitat, multi-lek females used larger home ranges than single-lek females. The great variation in female home range size did not agree with Bradbury's hotspot and female-preference hypotheses, indicating that female home range size may be unsuitable in revealing clues about lek evolution in capercaillie.

To investigate the effect of timing, frequency and duration of incubation recesses of female grouse on predation, thermistors were placed in 29 nests of capercaillie Tetrao urogallus and 10 nests of black grouse Tetrao tetrix in southeast Norway during 1983–84. Two female capercaillie were killed by goshawks Accipiter gentilis during recesses and 15 capercaillie and three black grouse nests were depredated. The incubation patterns of 20 capercaillie and nine black grouse were measured during 165 and 75 days, respectively. There was no difference between species in how long females stayed away from the nest each day, but black grouse took more and shorter recesses than capercaillie. The recess activity of both species peaked before and after a period of low activity during the night. Although black grouse took the first recess earlier and the last recess later than capercaillie, they also took few recesses in dim light. Nest losses were not associated with the time or frequency of departures from the nest. The data presented suggest that factors other than predation risk may be responsible for the patterns of incubation recesses observed in grouse.

Crosses between male black grouse Tetrao tetrix and female capercaillie T. urogallus are the most common grouse hybrids. Some male hybrids (F₁-generation) may be fertile and produce offspring (F₂-generation) with females of capercaillie and, rarely, black grouse. Specimens and descriptions of lek behaviour are also available for probable F₃- and F_>3-hybrids. Three and two male F, hybrids were documented to display simultaneously on a black grouse lek in Norway (1993–1997), and solitarily displaying hybrids were documented on black grouse leks in the Czech Republic (1960–64), Sweden (1991–93) and Norway (1992). Mating of hybrid males with female capercaillie was observed in 1992 and 1994. The lekking behaviour of the hybrids and their attitudes towards other tetraonids are described.

Survival rates are necessary for calculating allowable harvests and for modelling population performance. Survival rates for 93 black grouse Tetrao tetrix equipped with radio tags in two populations of the southern French Alps were estimated. Annual survival rates of hens (0.68, SE = 0.075, 0.84, SE = 0.105), but not of cocks (0.56, SE = 0.09, 0.66, SE = 0.122), tended to be higher than those of juveniles (0.52, SE = 0.071, sexes combined). The lower survival of juveniles was due to higher predation, mostly by raptors, in autumn and winter. Although both autumn and winter were seasons of peak mortality in juveniles, most adult deaths occurred either in spring (hens and cocks), or in early summer (cocks). Causes of mortality were as follows: raptors 51%, mammalian predators 27%, unidentified predators 11%, and hunting 11%. Principal raptors were golden eagltAquila chrysaetos and goshawk Accipiter gentilis. Mammalian predators included fox Vulpes vulpes, pine marten Maries maries and stone marten M. foina. Only males could be legally shot, and hunting was a minor mortality factor on our study areas. Nevertheless, the distorted adult sex ratio favouring hens that we observed on our study areas was probably due to hunting of males on and around the study areas. Sensitivity analysis showed that population growth is influenced more by adult survival than by either reproductive success or juvenile survival to one year of age. To prevent shooting from causing highly distorted spring sex ratios, which might compromise reproductive success, harvests should be reduced in years of poor reproduction, and shooting should be oriented towards juvenile males.

In a study area situated in the eastern Italian Alps, samples of the main ingredients in the diet of male black grouse were collected nine times between September 1993 and December 1994 and analysed for crude protein (CP) content and cell wall components (NDF, ADF, ADL). The mean monthly chemical composition of the diet was calculated on the basis of the percentage of dry matter (DM) weight of the main ingredients in the crop or gizzard, estimated in a previous experiment with 100 male birds shot in the same region in the periods April-June and September-December. Dietary CP reached its maximum value in spring (17.4 and 14.5% DM in May and June respectively), and its minimum in autumn (8.4% DM). Non-protein cellular solubles (NPS) were particularly high (66.7% DM) in September. The NDF content was highest in May (52.5% DM) and lowest in autumn, when it increased linearly from September (24.7% DM) to November (35.3% DM). The variability of the diets could be described by two principal factors, the first of which was correlated with the level of fibrous constituents and the second with the protein level and an ingredient diversity index (DI). In the plane defined by these two factors, five different types of diets were identified by cluster analysis; one diet distributed over all months was associated with two ‘spring’ and two ‘autumn’ diets. The first, ‘basal’ diet had intermediate chemical characteristics (CP 10.2% DM; NDF 37.1% DM) and a relatively high DI (3.3). The two spring diets had very high (CP 18.1% DM; NDF 64.7% DM) or high (CP 11.9% DM; NDF 46.7% DM) protein and fibre levels, due to the selection of beech Fagus sylvatica buds or bilberry Vaccinium myrtillus or larch Larix decidua shoots and needles. The two autumn diets had a high concentration of NPS (70.5% DM and 61.2% DM) due to the presence of fruits, particularly from bilberry and cowberry Vaccinium vitis-idaea; they differed in their DI (2.6 vs 3.5) and the partial substitution of bilberries by bilberry shoots and Rhododendron spp. buds and leaves in the second diet.

The breeding performance in yearling and adult female black grouse Tetrao tetrix was studied in a 6–7 year cyclic population during 1989–93 in central Finland. Eighty yearlings and 108 adults, radio-marked in late winter, survived until the breeding season. Adults were larger, had more body mass at capture, initiated laying earlier and had larger eggs and clutches than yearlings. Yearlings and adults lost 11.8 and 20.9%, respectively, of their first nests to egg predators. Hatching dates and success of eggs were similar for both age classes. The proportion of females losing the entire brood was 32% for yearlings and 27.1% for adults. Brood size in late summer and number of chicks produced per female initiating breeding did not differ between age classes.

The seasonal mortality of black grouse Tetrao tetrix was studied in southeastern Norway (60°26′N, 10°54′E), in a study area dominated by up to 80% Norway spruce Picea abies. Modem forestry with clear-cuttings has been practised, and 50% of the forest was younger than 30 years. Fourteen males and seven females were captured on a lek in spring 1991 and equipped with radio transmitters. During the following 12 months, 72% of the birds were killed, mostly by predators. No birds died from capture through July. In autumn, predation was higher, with four black grouse being killed. Mortality was highest during winter, with 58% of the birds dying. The goshawk Accipiter gentilis was the most important predator during winter. High predation by goshawks in winter 1991–92 may have been the result of black grouse being more vulnerable to predation because limited snowfall precluded snow roosting, or of an invasion by goshawks. Therefore, snow roosting may be an important antipredator behaviour in black grouse. The effect of increased adult mortality is discussed in relation to chick production.

The broad altitudinal distribution of ptarmigan Lagopus spp. makes this group an excellent model with which to ask how morphological and physiological specializations foster successful reproduction of birds at their distributional limits. Eggshell conductance and permeability to gases, shell surface area, shell thickness, daily water loss, and egg volume were measured in willow ptarmigan Lagopus lagopus breeding at 720 m a.s.l. and whitetailed ptarmigan Lagopus leucurus breeding between 3,600 and 4,100 m a.s.l. Of these characteristics, only egg volume and shell surface area differed significantly between the two species. Since the rate of daily water loss is similar at the two breeding locations, embryos develop in similar hydric environments inside the shell. High altitude embryos facilitate oxygen delivery with acclimatory adjustments in certain cardiovascular and cellular characteristics.

The effects of predation risk, body condition of females, and microclimate at the nest site on timing and length of incubation recesses at 30 nests of white-tailed ptarmigan Lagopus leucurus were examined. Incubation patterns in 1994 (an early year) were also compared to those of 1995, an unusually late spring with low temperatures. Data on incubation schedules were obtained by placing programable temperature data-loggers in nests and by direct observation of incubating females. Some egg depredation was associated with movements of hens to and from nests, but there were no apparent differences in risk between crepuscular recesses and daytime recesses. Ptarmigan showed high nest attentiveness (>90%) in both years of the study but took significantly more recesses of longer duration in 1995 than in 1994. This suggests that the amount of recess time was affected by body condition of the female which was lower during incubation in 1995. The overall number of recesses per day did not vary according to cover at the nest site; however, females with nests that had no overhead cover did not leave during the warmest part of the day. It is suggested that timing of recesses in this population of ptarmigan is related to microclimate and body condition, rather than being a strategy to avoid predation.

Available data indicate that sage grouse Centrocercus urophasianus have declined throughout their range. This species presently occurs in 11 U.S. States and in two Canadian provinces. In nine states having long-term data, breeding populations have declined by 17–47% ( = 33%) from the longterm average. Six states have long-term information on sage grouse production. In five of these states, production has declined by 10–51% ( = 25%) from the long-term average. Habitat deterioration, loss, and fragmentation have reduced the quantity and quality of nesting and early brood-rearing habitat causing population declines. Factors appearing to be largely responsible for the changes in habitats and, ultimately, sage grouse populations over wide areas of western North America are discussed, and hypotheses that could be tested to provide better insight into sage grouse population declines are suggested. Once these changes are better understood, conservation strategies that address protection and rehabilitation of sagebrush Artemisia spp. rangelands should be developed and implemented in each state and province to halt the decline of sage grouse and initiate recovery.

Sage grouse Centrocercus urophasianus have been translocated in at least seven states and one Canadian province, but little published information documents the success of these attempts. Historical and recent efforts at translocations are reviewed, their success evaluated and recommendations for future translocations are provided. Over 7,200 sage grouse have been translocated in at least 56 attempts to augment or reestablish populations since 1933. Only efforts in Colorado, Idaho, and Utah appear successful, however, breeding populations in these areas remain small. Common features of successful sage grouse translocations are: 1) reproductively-active birds were captured on leks at night in March and April, 2) birds were transported rapidly and released the morning following capture, and 3) release sites were isolated, islands of habitat surrounded by inhospitable cover distant from capture areas. Translocation of sage grouse is recommended only after careful evaluation of the release area for year-round habitat, and only if agencies commit resources adequate to monitor birds immediately postrelease to assess short-term survival, and to monitor long-term population abundance to assess continued fate of the translocation. Translocations presently should be viewed as experimental and not as a viable strategy to restore extirpated populations of sage grouse.

Energetic models which incorporate environmental measures have demonstrated that significant thermoregulatory savings are accrued from nocturnal winter roost-sites, usually from reduced wind speed and radiated heat loss. Because blue grouse Dendragapus obscurus occupy high elevation, snowbound coniferous stands in the Rocky Mountains during winter, selection of a favourable microhabitat is likely their primary thermoregulatory behaviour. Therefore, we measured the microclimatic conditions at diurnal and nocturnal roost-sites of blue grouse to determine whether their choice of roost-sites reflects thermoregulatory behaviour. Temperature, wind speed, and solar radiation were measured at 17 diurnal Douglas-fir Pseudotsuga menziesii and 17 nocturnal subalpine fir Abies lasiocarpa roost-sites and compared to those of an open control site in Logan, Utah, 1985–1986. Temperature varied <2°C between the roost-sites and the control site. Wind speed was significantly lower in 15 of 17 diurnal ( = 0.71 m/sec) and all nocturnal roost-sites ( = 0.24 m/sec) than in the control site ( = 1.75 m/sec). Wind speed was reduced >75% at all but one nocturnal roost-site. Solar radiation at the diurnal roost-sites ( = 51 W/m^-2) was significantly lower than at the control site (201 W/m^-2); however, five roost-sites had maximum values >90% of the control maximum. Douglas-fir roost-sites had significantly greater solar radiation, diurnal, and nocturnal wind speed than subalpine fir roost-sites. Reduction of convective heat loss was the major thermoregulatory contribution of both diurnal and nocturnal roostsites. Diurnal roost-sites also afforded measurable radiant energy and, presumably, grouse could track the sun in roost trees to maximize such heat input. Daily energy costs predicted from metabolic equations incorporating temperature and wind speed were below the metabolizable energy intake of captive blue grouse. Application of the average microclimatic conditions from both roost trees to an energetic model revealed that a blue grouse would realize a 50% greater reduction in convective heat loss, and a 10% greater net energy savings, by roosting overnight in a subalpine fir rather than a Douglas-fir. This difference may explain why blue grouse show affinity to subalpine firs for nocturnal roosting, and points to the energetic importance of specific coniferous habitats to wintering blue grouse.

Hazel grouse Bonasa bonasia encounter more severe climates in northeastern Asia than anywhere else in their range, yet the time between snow melt and laying is shorter here than elsewhere. Birds were able to lay early because they moved to follow the phenology of snow melt, changing their diet as they did so. Before snow melt, habitat distribution and diet were the same as in winter. As soon as the first snow-free patches occurred on terraces, grouse moved there and fed on thawed berries, which were available in great quantities on these terraces only. This habitat shift coincided with the shift in diet; winter foods such as twigs, buds and catkins decreased from 75 to 3%, whereas the proportion of berries increased from 6 to 70%. Females began to lay a few days after all snow had melted, returning to riparian habitats where the variety and abundance of plants were greatest. Foliage increased from 27 to 72% of the diet, and the proportion of berries declined from 70 to 19%. In winter, Asian hazel grouse primarily occur in flocks. In spring males guard their mates rather than their territories; they follow females up to a few kilometres from their riparian breeding habitats, as these move on to terraces to gain weight for egg laying. Such food related movements between habitats have not been reported for this species in Europe.

Brood movement and natal dispersal of hazel grouse Bonasa bonasia at Changbai Mountain were studied using radio telemetry in 1993–94. Most chicks hatched during late May to early June. Only hens accompanied three radio-tracked broods. After wandering for 30–35 days, broods 1 and 3 became relatively sedentary in second-growth forest, 1.6–1.7 km from their nests. Broods 1 and 3 disintegrated when chicks were 80 and 69 days old. Based on radio-tracking, it is suggested that the impetus for one brood's disintegration was that the hen left its brood. Female 2 lost her chicks about 20 days after hatching. The hens returned to their spring home ranges after brood dissolution. Three radio-marked chicks dispersed 4.8–5.7 km in mid-September. It is concluded that, in general, the hazel grouse is an active disperser in natural habitats.

The mating behaviour of Chinese grouse Bonasa sewerzowi at the Lianhuashan Natural Reserve in Southern Gansu Province was studied in 1995. Eleven birds were radio-marked during the breeding season. Pair formation began in late March. Males held territories of 1.8–3.2 ha (N = 3). The ‘flutter-jump’ behaviour was believed to be used by males for advertising territories and attracting females. It also could serve as a warning signal. Males competed for females in April and May, but not all males paired with females. Female-female aggression was not observed. The mating system of Chinese grouse was primarily monogamous, however, the possibility of polyandry or extra-pair copulations remains. In addition, female choice was believed to be the main factor affecting pair formation.

The black grouse Tetrao tetrix is declining in most of the Alps where it historically occurred. A better knowledge of the genetics of the wild populations and of captivereared birds is necessary for future reintroduction into areas where they historically occurred or where they are endangered. DNA-markers are the choice of method to study genetics of wild populations, but it is difficult to get blood samples from wild birds to extract DNA. A technique based on feathers as the DNA source was developed. DNA extracted from blood and feathers from seven birds was tested by PCR, 80 10-base primers. Only seven primers showed a repeatable amplification profile between DNA sources and polymorphic variation within the population. The selected primers were used to amplify the DNA extracted from wild black grouse feathers in different areas (Trentino, Cuneo, Maritime Alps). The Trentino population presented a reduced genetic variability with an average band sharing (ABS) of 0.76 ± 0.145 in the captive-reared birds vs 0.70 ± 0.17 in all birds. The birds from Cuneo and the Maritime Alps had an ABS of 0.48 ± 0.07 and 0.35 ± 0.10, respectively, and were quite different from the average genotype.