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Annual, nationwide monitoring of the grouse (hunted tetraonid birds) began in Finland at the beginning of the 1960s followed by systematic counts of mammal snow tracks in the late 1980s. The wildlife triangle scheme, started in 1989, gathers game monitoring data throughout the country. The system is based on a large network of triangles made up of 4 km transects (totaling 12 km per triangle) covering the entire country. The program involves an astonishing amount of fieldwork: about 10 000 km of transect line (about half of the established transects) is studied during every summer and winter count. The riistakolmiot.fi internet service was launched for the 2014 late-summer count. Via the internet, trained hunters can record their observations in a database and follow the progress of the count during the fieldwork period. In the public section of the website, anyone can view the results of ongoing counts. The internet service speeds up the collection of observations, simplifies the storing of data, and assists in preparing and sending the summary reports. Data provided by the wildlife triangle scheme are utilized by the European Union, the Ministry of Agriculture and Forestry, and other game administrative organizations, as well as hunting clubs and the general public. Annual results of the late-summer monitoring procedure are used immediately when deciding on the restrictions to the forthcoming grouse hunting season, which is due to begin just a few weeks later.

Natal dispersal distances are difficult to measure, yet important for estimating the genetic structure and demographic connectedness of natural populations. Here we provide estimates of the distributions of male and female natal dispersal distances from a long-term study of Spruce Grouse (Falcipennis canadensis (L., 1758)) in southwestern Alberta, Canada, based on individuals marked as brood chicks and re-observed as adults during subsequent breeding seasons. The mean distance dispersed by females (2.33 km) was twice that of males (1.13 km), and both dispersal distributions were leptokurtic. Given estimates of population density and survivorship, we estimated the genetic effective neighborhood size of this population as approximately 541 individuals. We computed equivalent estimates for two additional long-term studies of this species, based on data available in the literature; mean natal dispersal distances, averaged across sexes, ranged from 1.73 to 2.73 km for the three populations; effective deme sizes ranged from 541 to 890. Consequently, three widespread populations of Spruce Grouse yielded roughly similar estimates of demographic and genetic structure.

Partial cuts are increasingly proposed to maintain habitats for species negatively affected by clearcutting, even if their benefits on nonpasserine birds and large mammals are still poorly documented. Our main objective was to evaluate effects of commercial thinning (CT) on spruce grouse ( Falcipennis canadensis L.), a game bird of the boreal forest. Because this species is known to be associated with a dense vegetation cover, we hypothesized that habitat use would be lower in treated sites. In spring 2006, we evaluated site occupancy in 94 forest stands (50 CT and 44 uncut stands) in Quebec by visiting each on three occasions during the breeding season (March–May). Additionally, during the molting period (May–July), we used radiotelemetry to monitor habitat use by 19 males. As compared with uncut stands, results show that a lower proportion of CTs were used in spring (39% versus 60%, after accounting for detection). During the molting period, CTs were also used less than expected according to their availability. The significant reduction of lateral and vertical forest cover in CT may explain these results. We conclude that even if CT is perceived beneficial for wildlife, it does not completely fulfill the needs of species associated with dense understory vegetation, such as spruce grouse.

Capercaillie ( Tetrao urogallus L., 1758) and black grouse ( Tetrao tetrix L., 1758 (= Lyrurus tetrix (L., 1758))) are two sympatric Eurasian lekking grouse species that differ markedly in habitat affinities and social organization. We examined how size and spacing of leks in pristine (Russia) and managed (Norway) forests were related to habitat and social behavior. Leks of both species were larger and spaced farther apart in the pristine landscape. Capercaillie leks were regularly spaced at 2–3 km distance, increasing with lek size, which in turn was positively related to the amount of middle-aged and older forests in the surrounding area. Black grouse leks were irregularly distributed at shorter distances of 1–2 km, with lek size explained by the size of the open bog arena and the amount of open habitat in the surroundings. At the landscape scale, spatial distribution of open bogs and social attraction among male black grouse caused leks to be more aggregated, whereas mutual avoidance in male capercaillie caused leks to be spaced out. In the pristine landscape, large-scale and long-term changes in forest dynamics owing to wildfires, combined with an aggregated pattern of huge bog complexes, presumably provide both grouse species with enough time and space to build up bigger lek populations than in the managed landscape.

Declines in ruffed grouse ( Bonasa umbellus (L., 1766)) populations in the central and southern Appalachians may be linked to low brood survival. Therefore, managing for high-quality brood habitat could improve grouse numbers. Understanding how brood habitat selection affects survival and the spatial scale at which this occurs is therefore fundamental to developing effective habitat management strategies. From 1999–2002, we monitored 38 broods for 5 weeks post hatch and estimated utilization distributions (n = 28), site-scale habitat use (n = 21), and daily survival rate (mean = 0.966, range = 0.920–0.997, and n = 19). Relative to available habitat, broods selected sites with greater herbaceous ground cover and higher small (

We determined the categories of roost sites used by ruffed grouse ( Bonasa umbellus (L., 1766)) during daytime in winter from 245 radiotelemetric locations of 26 adult females. We conducted our study in the Réserve faunique de Portneuf, located in a mixed nordic-temperate softwood–hardwood forest in Quebec, Canada. We evaluated the effects of weather, snow, and habitat variables on the incidence of snow burrowing, tree roosting, and on-snow roosting using mixed multinomial models, ANOVA, and logistic regressions. The best logistic regression model of snow burrowing probability was identified using the Akaike path. The incidence of each category of roost sites was 41.2% tree roosts, 36.3% snow burrows, and 22.4% on-snow roosts. Coniferous canopy closure and depth of fluffy snow were the variables that influenced roosting behavior the most. Probability of snow burrowing increased with compaction depth and decreased with coniferous cover. Probability of tree roosting increased with temperature. On-snow roosts had a denser lateral obstruction than snow burrows, whereas tree roosts had a greater coniferous basal area, stem density, and canopy cover than snow burrows. Stand type also influenced the incidence of each category of roost sites, snow burrows dominating in deciduous stands and tree roosts dominating in mixed and coniferous stands.

We measured the rate of water loss and pore density of eggs of spruce grouse ( Canachites canadensis canace (L., 1766)) and ruffed grouse ( Bonasa umbellus togata (L., 1766)) from different parts of their range in Ontario. Eggs were dried in enclosed glass jars over Drierite® and in paper trays in open air at room temperature and humidity. Eggs were weighed to the nearest 0.01 g every 2–4 days and the change in mass was measured as water loss. Pores of shells were counted (pores/cm2) in the blunt, middle, and pointed sections of the egg. Eggs of spruce grouse lost water at a faster rate in Drierite® and in open air and had a greater density of pores than eggs of ruffed grouse. Rates of water loss were constant and varied inversely with ambient humidity, with the difference between species greatest in open air. Eggs late in incubation of ruffed grouse dried at a faster rate than those early in incubation in Drierite®. The adaptations of eggs of each grouse to the moisture of the nest may help explain their distribution, density, and habitat and nest-site selections, as well as behavioural aspects of the nesting hen. Both, especially the spruce grouse, may be good indictors of climate change.

Capercaillie (Tetrao urogallus L., 1758), the largest and most size-dimorphic species of grouse, is decreasing in number throughout its man-modified range in the boreal forests of the Palaearctic. Poor reproduction owing to direct and indirect effects of commercial forestry is considered a main cause of the decline. We studied brood habitats in a pristine forest in northwestern Russia to identify key elements in habitat selection in the natural environment of this species. We monitored the movement of 10 radio-marked broods during their first 7 weeks of life, and compared the abundance of insects and cover at their locations (N = 120) with nearby random control sites. The broods preferentially used moist spruce forest and the insect-rich herb spruce forest, but were most often located in the more abundant vaccinium spruce forest, which was richest in bilberry (Vaccinium myrtillus L.) and associated lepidopteran larvae. Brood locations were consistently richer in insects than random controls in 3 of the 4 habitat types studied. The most pronounced difference was in the density of lepidopteran larvae, a food source known to form an important part of the diet of young capercaille chicks. Broods continued to select insect-rich sites throughout the 7 week age period; in the preferred moist spruce forest, larval abundance increased at brood locations, while it remained constant at control sites. Compared to the distribution of insects, cover did not appear to be as an important determinant of brood habitat selection, possibly because the structural characteristics were rather similar among the most widely used habitat types. Shrub cover tended to be higher at brood locations than at controls, whereas vertical cover along the ground was not different. This relationship to cover factors may reflect an adaptation to avoid predation by goshawk (Accipiter gentilis (L., 1758)), the most important predator of grouse in this pristine boreal forest.

We studied the short-term impact of cutting with the protection of regeneration (CPR) on ruffed grouse (Bonasa umbellus) and its habitat. Drumming males were surveyed in the boreal forest of western Quebec between 1990 and 1994 in 5 control stands and 10 stands that were cut in 1992. Cutting caused a 50% decline in total density and basal area of trees. In harvested stands, shrubs were less abundant than in control stands. Lateral cover between 1 and 2 m and canopy closure were also lower in cut stands. In the harvested stands, the density varied between 14.1 and 22.6 drummers/km2 between 1990 and 1992 before the CPR. In 1993, density declined to 10.1 but was reestablished at 21.5 in 1994. Densities did not differ significantly before or after the CPR nor between cut and uncut stands (p > 0.05). After the CPR, the grouse generally established their drumming sites in the periphery of cut areas. There they found lateral cover and canopy closure similar to those measured in control stands by choosing sites where deciduous shrubs were more abundant than in the remainder of the stand. However, the characteristics of the tree stratum were not optimal; their overall density, that of Betulaceae, and that of Salicaceae were higher near drumming sites located in control stands than those in harvested stands. In harvested stands, drumming sites had a lower total basal area of trees, and namely that of deciduous trees, than in control sites. To maintain ruffed grouse populations immediately after cutting in mixed and deciduous stands of public lands, we suggest that CPRs be in 15-ha blocks while maintaining a basal area of at least 7.5 m2/ha, half of which should be in trembling aspen (Populus tremuloides Michx.) and paper birch (Betula papyrifera Marsh.).

One hypothesis to explain low densities of ruffed grouse (Bonasa umbellus) in the southeastern United States is that available winter forages in the Southeast require more time to harvest than forages eaten in the central portions of the species' range, where grouse densities are greater. Longer foraging times could increase mortality rates through greater predation risk and higher energy expenditure. To test this hypothesis, we conducted trials with captive ruffed grouse to determine their maximum instantaneous rates of intake of various forages and used the results to estimate minimum foraging times for southeastern ruffed grouse consuming an average winter diet. Grouse in the Southeast must forage for > 100 min to meet their energy demands. Ruffed grouse in the central portion of the range rely heavily on aspen (Populus sp.) buds during the winter and can consume the same amount of metabolizable energy in 30–50 min. Thus, we present evidence that ruffed grouse in the southeastern United States must forage for longer periods to meet daily energy demands and therefore may experience higher winter mortality rates.

Forages in boreal ecosystems are often deficient in sodium for mammalian herbivores. Moreover, consumption of various plant secondary metabolites has been associated with negative sodium balance in mammals. Neither of these issues has been investigated in birds, which differ from mammals in their ion-exchange processes and postrenal absorption of urine. Our objectives were to determine if ruffed grouse (Bonasa umbellus) can maintain sodium balance on quaking aspen (Populus tremuloides) flower buds, an important winter food, and to determine if the buds' primary plant secondary metabolite (coniferyl benzoate) further compromises a bird's sodium balance. Captive ruffed grouse were fed either aspen buds (0.063 mg∙g−1 sodium) or a formulated diet having different concentrations of coniferyl benzoate in no-choice feeding trials. Sodium excretion did not change in response to coniferyl benzoate intake or acid load from detoxication processes; however, birds were marginally in negative sodium balance (P = 0.035; −5.06 ± 2.05 mg∙kg−1∙d−1) when feeding on aspen buds. Sodium levels in the feces from free-ranging grouse (0.050 ± 0.0 mg∙g−1) and in their winter foods (0.065 mg∙g−1) indicated that these birds likely maintained sodium balance. We estimated that free-ranging ruffed grouse may need as little as 7 mg∙kg−1∙d−1 of sodium to maintain sodium balance, which is lower than the minimum sodium requirements for poultry and mammals.

The summer diet of the mountain hare (Lepus timidus L.) was studied in a low-alpine area in southern Norway. Dietary preferences were determined for 11 hares in cafeteria trials. The hares were later equipped with radio transmitters and released, and diet selection was observed directly. The results demonstrate that mountain hares seem able to utilize a wide variety of different plants, although they selected herbs in the field. Based on the available literature, diet overlap and diet niche breadth were estimated for five sympatric herbivores; reindeer, sheep, willow grouse, Norwegian lemming, and mountain hare. Generally, the noncyclic herbivores had broader diet niches and greater dietary overlaps than the cyclic herbivores.

We measured the field metabolic rate (FMR) of seven free-ranging and two captive blue grouse (Dendragapus obscurus) with doubly labeled water. Average carbon dioxide production (1.016 ± 0.088 L CO2∙kg−0.734∙h−1) of free-ranging grouse was 8% higher but not significantly different (P 2∙kg−0.734∙h−1). Ambient temperature was not correlated with FMR (P = 0.268). The mean fat content of free-ranging blue grouse was 39 g (3.4%), which was equal to the energy equivalent of about 3× daily standard metabolie rate (SMR). The FMR of free-ranging grouse averaged 657 ± 62 kJ/d or 1.6 × SMR. The FMRs of free-ranging blue grouse averaged about 25% below FMRs predicted from allometric equations; most were 35–40% below those predicted. We suggest that there is little energetic constraint on blue grouse during winter because they are able to maintain a positive energy balance by minimizing energy costs through effective thermoregulation, microhabitat selection, and reduced activity.

Sympatric forest grouse in intensively managed conifer-dominated forests of the southern boreal zone in Sweden occupied different forest successional stages. Black grouse (Tetrao tetrix) selected forest stands 0 – 20 years old, hazel grouse (Bonasa bonasia) selected those 20 – 50 years old, and capercaillie (Tetrao urogallus) selected those ≥90 years old. Moreover, hazel grouse also selected stands with 1 – 10% deciduous trees, whereas capercaillie selected stands with no deciduous trees. The relative numbers of each grouse species were similar in two areas of intensively managed industrial forest, but differed in an area where forestry was less intensive and where forests had old-growth characteristics, i.e., they were old and multi-layered. Black grouse dominated in the intensively managed areas, whereas hazel grouse dominated in the less intensively managed area. We suggest that under natural conditions, black grouse inhabited the early-successional stages of forest following burns, hazel grouse inhabited the next, denser, successional stage and also old-growth spruce-dominated forests in fire refugia, and capercaillie inhabited stands of open, old, pine-dominated forest maintained by forest fire. The black grouse appears to be preadapted to the modern system of clearcut forest management. However, this system is clearly detrimental to the hazel grouse and capercaillie. To maintain all three species in a managed landscape, forest managers must strive to mimic more closely the natural variation in types and sizes of forest stands.

We developed a primary feather wear index (WI) for blue grouse (Dendragapus obscurus) to examine variations in courtship activity among males. Three percent of 276 yearling males, and less than 1% of 144 yearling and adult females examined throughout spring and summer showed evidence of such wear. Among 630 adult males, 48% exhibited "courtship wear." Mean courtship wear among males 2 years old and older increased steadily throughout the spring and summer, generally paralleling what would be predicted from cumulative reproductive activity. However, there was much variation among males, ranging from no wear to heavy wear, even by late summer. These data are consistent with earlier suggestions that breeding may be skewed among male blue grouse, as in lek-breeding tetraonines. Limited samples indicate that primary feather wear was not related to the age of males (more than 1 year old) or their occupancy of persistent or transient territorial sites.

Survival of dispersing spruce grouse equipped with radio transmitters was studied in central Ontario during autumn 1986 and 1987. Ninety-two percent of females and 74% of males dispersed from brood range. Females dispersed farther than males in only 1 year. Birds that dispersed did not exhibit lower survival than birds that did not disperse. There were no meaningful differences in survival between birds that dispersed and birds prior to dispersal, between short- and long-distance dispersers, or between sexes. Dispersal did not appear to contribute unduly to mortality.

An audio index was developed for estimating the density of male spruce grouse (Dendragapus canadensis). The index is based on counts of fluttering males heard during hikes at dawn, and is derived from work carried out in New Brunswick and Ontario over a period of 7 years. Densities of males were determined over 6 years; the number of males heard fluttering per hour of hike correlated well with male density (r = 0.91).

Whether the ability of males to attract renesting females (female attraction) adequately explains the termination, or the persistence, of display by male grouse in late spring was evaluated. In 7 of 8 years and (or) locations, advertising display (fluttering) by male spruce grouse (Dendragapus canadensis) at dawn ceased or became sporadic soon (≤9 days) after the median date on which females were estimated to have commenced laying eggs. Early cessation of display is consistent with the proposal that there is little reproductive gain for males in continuing to display if nesting success is high; hence, female nesting chronology drives the pattern of display by males in spring. Male–male interactions and colonizing effort, and the risk of display and the probability of survival to the next year, could also determine the timing of the cessation of display, and these factors are discussed, along with the female-attraction hypothesis.

Observations of foraging birds showed that the summer diet of adult and juvenile spruce grouse (Dendaragapus canadensis) in southwestern Alberta included 31 taxa of fungi, vascular plants, and animals. The genus Vaccinium was confirmed as the major food source for these grouse during summer. For the first time, however, conifer needles and fungi were recorded as important components of the diet at this time of the year. The latter observations raised questions about the potential for bias, particularly in terms of the type of the food ingested and the time of day when it was consumed, in studies of the food habits of galliforms that are based only on analyses of crop contents.

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.

We used instrumental neutron-activation analysis to determine the concentrations of Br, Mn, Cl, Al, and Na in primary feathers 1, 9, and 10 of Spruce Grouse (Dendragapus canadensis) in four jack pine (Pinus banksiana) forests in northern Ontario. Our objective was to see if there were consistent trends in intrapopulation variation of mineral profiles among populations. Except in the case of Na concentration, there were significant sources of variation attributable to age (adult versus chick) and sex in all forests, and there were large differences among study sites. Yearling and adult grouse that recruited to the breeding population differed in the elemental composition of their feathers from long-term residents of the same age. Information on intrapopulation variation, which traditionally has confounded studies of geographic variation, may have useful applications in research and management. If trends are repeatable and predictable, feather profiles may be used to identify the age or sex of a bird and the origin of recruits on a microgeographic scale.

We measured the effects of temperature (Ta) on the metabolic rate of 6 blue grouse (Dendragapus obscurus) during winter with indirect respiration calorimetry. The standard metabolic rate was 0.812 L O2∙(kg0.734)−1∙h−1 and was 24% higher than that predicted allometrically. The lower critical temperature (Tlc) of fasted grouse was −5 °C; metabolism increased linearly below −5 °C. The heat increment associated with a Douglas-fir (Pseudotsuga menziesii) diet lowered the Tlc by 5 °C From −5 to −20 °C, the metabolism of fasted and fed grouse increased by 30 and 12%, respectively. A positive winter energy balance was predicted for blue grouse from estimates of the field metabolic rate and the consumption and assimilation rates of a Douglas-fir diet.

The three North American ptarmigan species are monogamous, whereas the other six North American grouse species are polygynous. In the Arctic there are few nest predators, which means ptarmigan should be prepared to nest nearer each other than polygynous grouse that lose more nests to predators. Hence, ptarmigan females search relatively small prelaying ranges for nest sites. The small space requirements of females allows males to economically defend with territorial behaviour the nesting resource (cover and space) that females will later search and require, and thus the fitness of males is determined by the quality of the nesting resource that he controls which results in selection by females. In the Arctic the open habitat, continuous daylight, and the presence of effective avian predators have resulted in females also selecting conspicuous, vigilant males in a prolonged pair bond. These males deflect predation risk away from females during nest searching and egg laying in all three species and from hens with chicks in willow ptarmigan.

The plasma concentration of prolactin was measured following experimental photostimulation, during oviposition and during incubation in plasma from ruffed grouse by heterologous double-antibody radioimmunoassay. A slight increase in plasma prolactin was noted after photo-stimulation and a much larger increase was observed as subsequent eggs were laid. When the last egg was laid, plasma prolactin was maximal. This high concentration was maintained throughout incubation and declined to basal values when incubation was terminated by removal of the eggs. In hens that failed to incubate, plasma prolactin declined after the last oviposition.Brood patch development began before the first egg was laid but was not completed until incubation was initiated. Therefore, the patch began to develop when plasma concentrations of prolactin were slightly elevated but it was not fully formed until high concentrations of prolactin were maintained for several days.

The influences of date of hatch, and age and prelaying body weight of brood female on the growth rate of juvenile spruce grouse (Canachites canadensis) were studied in central New Brunswick in 1977 and 1978. Because of differential timing of hatch of broods of adult and yearling females, it was not clear whether a difference in juvenile growth rates during 5–14 days of age in 1977 was related to date of hatch, age of brood female, or both. Differences in juvenile growth rates within and between years apparently were not influenced by body weight of brood females prior to egg laying. Results suggest that posthatch factors are more important in determining growth rate than a prehatch or "maternal" influence.

The behavior of female Franklin's grouse (Canachites canadensis franklinii) in response to a playback of female aggressive calls was recorded in southwestern Alberta during the spring of 1974 and late winter, spring, summer, and autumn of 1975. Resident adults initially responded with aggressive calling during late winter and continued to call in response to the recording throughout spring. Only those overwintered yearlings that were establishing spring territories within their winter ranges responded by calling in early May. The onset of aggressive calling by resident yearlings coincided with the spring dispersal of those yearlings that were either not responding overtly or were fleeing from the site from which the sound was emanating. Dispersing yearlings only called aggressively after spring dispersal when they had established territories. The highest level of aggressive calling occurred when females were evenly spaced on territories and included the periods of mating and laying. Aggressive behavior thus appears to be a manifestation of female territoriality with a resulting uniform spacing during spring. It also appears to be a mechanism for adjusting the density of females in a local breeding population.

The characteristics of the fall phase of dispersal for 41 female and 88 male juvenile spruce grouse (Dendragapus canadensis) were analyzed for data collected between 1965 and 1984 in southwestern Alberta. Females moved significantly farther than males. Reasons for this difference were sought in location of wintering areas, timing of brood breakup relative to that of brood hen migration, and distance moved by the migrating brood hen. Wintering areas, encompassing blocks of forest within which more than 80% of adults passed the winter, represented less than 15% of the study area. These areas were apparently also the destination for a high proportion (84%) of the juveniles. Distances moved are believed to be influenced by the location of the wintering areas in relation to the direction taken by juveniles after brood breakup occurs, as well as the timing of this event in relation to the timing of migration in adult hens. Brood breakup of juvenile males preceded that of females (median 4 and 15 September, respectively), and dates of brood hen migration overlapped those of brood breakup (median 13 September). Hence, longer distances moved during the fall phase of dispersal (and a greater disappearance rate) by juvenile females relative to males may be caused by their later median date of brood breakup and consequently the increased probability of their moving with their migrating brood hens. This possibility is supported by the observation of intact broods following the migratory paths of their mothers. The data suggest that once the brood breaks up, juveniles may stop at nearby wintering areas.

The relative aggressiveness and proportion of time spent singing (incidence of singing) were assessed for male blue grouse (Dendragapus obscurus) occupying high- and low-quality territorial sites. Playback experiments were used to assess the relative aggressiveness of males; no support was obtained for the hypothesis that males on high-quality sites are more aggressive than those on low-quality sites. Prior experience with an area may be more important than aggressiveness in determining the quality of territorial site that is obtained. In 1 of 2 years, males on high-quality sites were observed hooting (singing) a greater proportion of the time than were males on poorer sites. A greater incidence of hooting by males on high-quality sites may be one factor that results in more females being observed near these males than near males on less suitable areas, as was found in a previous study.

In the springs of 1978 and 1979 we removed all male blue grouse (Dendragapus obscurus), both original occupants and subsequent replacements, from a series of persistent and transient territorial sites (those used regularly and intermittently, respectively). In both years more replacements settled on persistent than on transient sites. Most replacement males were adults, most of which likely would not have taken territories had we not made these sites available. The presence of nonterritorial adults, reported here for the first time, suggests that territorial behaviour limits breeding densities of male blue grouse. Testes of replacement adults, although smaller than those of resident males collected at comparable times, all contained mature sperm. Yearling males are seldom territorial; but of eight that took territories on removal sites all except one selected persistent sites.

The demography, behavior, and genetics of a population of blue grouse (Dendragapus obscurus) that colonized an area from which most grouse were removed were compared with those of grouse on a nearby control area. Population density increased on the removal area from 1971 to 1974 but remained essentially stable on the control area. Although there were some differences in survival and reproductive rates among years and between areas, none appeared related to the experimental removal and subsequent replacement by new founders.No consistent differences in potentially aggressive behavior were observed between birds in the two populations. Behavioral differences that occurred were likely related to differences in age structures of the two populations or to the synchronous settling of a cohort of mostly young birds on the experimental area.There was no excess of Ng (Birdsall, α., J. A. Redfield, and D. G. Cameron. White bands on starch gels stained for esterase activity; a new polymorphism. Biochem. Genet. 4: 655–658 (1970)) homozygotes among recruits to the experimental area, in contrast with Redfield's (Demography and genetics in colonizing populations of blue grouse (Dendragapus obscurus). Evolution, 27(4): 576–592 (1974)) report of such an excess among birds colonizing new habitat.The increase in the population on the experimental area compared with the control area must have resulted from an increased recruitment of yearlings. No clear evidence was found that this increase was related to qualitative differences between stocks on the two areas.

Copper, nickel, and iron levels in the crop items and dung of ruffed grouse (Bonasa umbellus) collected near the copper–nickel smelters at Sudbury, Ontario, during May and September were up to 50-fold higher than those of grouse from an uncontaminated area. Major crop items varied seasonally but did not differ between birds from the two sites. Levels of copper and iron in several body tissues did not differ between birds from the two areas. Mean copper levels in the kidneys, livers, and breast muscle ranged from 11.7 to 24.6, 12.6 to 16.3, and 1.5 to 2.3 μg∙g−1 of ovendried weight, respectively; mean iron levels in these tissues ranged from 254 to 395, 1899 to 3905, and 11 to 20 μg∙g−1, respectively. Nickel levels, however, were elevated in the kidneys and livers of Sudbury area birds; mean nickel levels in these tissues were 2.5 and 2.3 μg∙g−1, respectively, at the Sudbury site, compared with 0.9 and 0.8 μg∙g−1, respectively, at the uncontaminated site. Nickel levels in the breast muscle of birds from the two sites did not differ and ranged from undetectable levels to 1.4 μg∙g−1. Iron and copper levels were higher in the kidneys and muscle of birds collected during May from both sites. Geographical and seasonal differences in metal content of grouse body tissues are discussed in relation to metal-contaminated diet items and the reproductive cycle.

Seasonal change in habitats used by spruce grouse (Dendragapus canadensis) in eastern Maine was studied from spring 1981 until autumn 1983. Forest composition averaged 88 and 90% conifer tree species for males and females, respectively. Red spruce (Picea rubens) and balsam fir (Abies balsamea) were the dominant trees present in all habitats at all seasons. Forest density of habitats used by grouse differed significantly by season and sex. During winter males and females used conifer stands that were denser than random plots. During spring and summer females used sites that were less dense than those used by males and had a more open canopy and more ground vegetation. Both sexes showed seasonal changes in the proportion of time observed in trees. By midsummer, males and nonbrood females exhibited a strong selection for larch (Larix laricina) trees. During autumn both sexes moved to habitats with an increased proportion of larch and were found in these trees greater than 75% of the time Larch needles were considered an important transition food to the winter diet of conifer needles.

Changes in spatial patterns and behavior of yearling male blue grouse (Dendragapus obscurus) equipped with radio transmitters were recorded during spring and summer, 1980 and 1981, on Hardwicke Island, British Columbia. Sizes of home ranges decreased and yearlings appeared to become less dispersed as the season progressed. Most birds moved off their initial home range and onto new areas on the breeding range by late summer although the timing of this movement varied among individuals. Interactions involving yearling males with females and territorial males decreased as the season advanced. Changes in spatial patterns and behavior appear to be related to seasonal changes in levels of hormones in yearling males.

Numbers of breeding blue grouse (Dendragapus obscurus fuliginosus) observed along standardized transects on Hardwicke Island, British Columbia, were significantly higher in early successional stages than in midsuccessional or old-growth forests. Numbers in old-growth and midsuccessional forests were not statistically different. Cover percentage of the herbaceous stratum may be an important component of the preferred habitat.

Spacial organization among lekking sharp-tailed grouse was investigated, in the spring of 1969, near Wainwright, Alberta, by sequentially removing territorial males from the centers of two arenas and recording the responses shown by remaining territory holders. Vacancies created on each arena were filled by an adjacent male or shared by two or three birds in contiguous territories. Central vacancies were filled in an orderly and predictable manner: first by males in a central group of territories, then by males in territories surrounding die central group, and finally by peripheral males. As the number of males on arenas was reduced, the area occupied by the system of territories also shrank. Thus, territory size remained constant as did density of males on the arena. The means by which the spacial configuration of territories was attained and maintained are discussed.

The loss of eggs from clutches deposited in simulated and natural nests of spruce grouse was investigated during the spring of 1983 in lodgepole pine forests of southwestern Alberta. Two-thirds of all clutches, both in simulated and natural nests, were partially or completely lost. Density of simulated nests had no impact on proportional loss. Evidence suggests that nests under a conifer-dominated canopy, in an area lacking extensive shrub coverage, and at distances greater than 15 m from trails were the most vulnerable to egg predators. We conclude that red squirrels were the principle predator destroying these clutches.

We present an analysis of survival of male blue grouse (Dendragapus obscurus) using known-aged individuals and examine the results in terms of the evolution of delayed breeding. Males had low rates of mortality and, among 2-year-olds, mortality rates of territorial and nonterritorial birds were the same. Up to 6 years of age, males had life expectancies of at least 2 years. Males that postponed breeding and survived had a 40–45% chance of eventually obtaining a high-quality site for a territory. If males had not delayed breeding they likely would have had to settle on areas where opportunities for breeding appear to be low. Thus, survival patterns of males are consistent with the hypothesis that it is advantageous for some males to delay breeding if high-quality sites cannot be obtained.

Gonadal cycles of adult and yearling female and male blue grouse (Dendragapus obscurus fuliginosus) collected from Vancouver Island, British Columbia, are described and compared. Reproductive organs of yearling females develop later, produce eggs at a lower oviduct weight, and regress faster to a lower oviduct weight than do those of adults. Yearling males, although most do not breed, go through the entire gonadal cycle and produce viable sperm. Testes of yearlings develop later, have a lower volume, and regress earlier than those of adults. Yearlings of both sexes appear less sexually mature than adults, but delays in or lack of breeding could be partly a result of social interaction with resident adults.

The density of male blue grouse (Dendragapus obscurus) on a 95-ha area was reduced artificially by approximately 75% in 1982. Density, movements, and breeding success of females on this area in that year were compared with those of females on the same area in 1981 (when density of males was undisturbed) and of females on an unmanipulated control area in 1981 and 1982. A reduction in male density had no apparent effect on the density of either yearling (potential recruits) or adult females, or the daily movements, timing of breeding, and breeding success of females. Home ranges of females were largest when male density was artificially reduced, but not significantly so. The larger home range sizes of females residing in an area with a very low density of males did not seem to result entirely from females searching for males with which to breed. Results of this study suggest that densities of male blue grouse have no apparent effect on densities of females or production of young, and support the hypothesis that densities of females in this species are regulated independently of males.

Behaviour associated with territoriality in female Franklin's spruce grouse (Canachites canadensis franklinii) was studied during the breeding seasons of 1976 and 1977 to determine how and when these grouse communicate their location to conspecifics and what role communication has in maintaining dispersion. Field observations of marked grouse indicated that resident females advertised their presence to conspecifics and probably maintained their territories by producing both vocal and nonvocal sounds that peaked in intensity during the period of mating and laying. These sounds included a Cantus ("aggressive call") that was sung from regularly used advertising perches at dawn and dusk and flight sounds produced by flying frequently through the territory at these times. The Cantus was also used by territorial females during interactions with both trespassing nonterritorial and contiguous territorial females. The territorial behaviour of breeding females, manifested by intrasexual aggression, appeared to play a role in spacing of nests and spring dispersal of some yearlings.

Behaviour of juvenile spruce grouse (Dendragapus canadensis), from hatching to brood breakup, was observed in 30 radio-tracked broods inhabiting lodgepole pine (Pinus contorta) forests of southwestern Alberta. The immediate posthatch period (first 20 days) was characterized by a close spatial relationship between the chicks and hen, with brooding being the dominant behaviour. Hens with broods appeared to respond immediately, both vocally and through movement toward their chicks, whenever the latter uttered the following calls: sreep, sury, seer, and purring. Brooding sessions decreased in frequency but not duration (median of 11 min) until they disappeared from the behavioural repertoire of the chicks at about 50 days of age. Hen–chick and intersibling distances increased as the chicks grew older. The breakup of broods appeared to result when the cohesiveness of the brood decreased to a point at which calls of the chicks no longer elicited a response from the brood hen. There was no evidence that agonism contributed to this decline in brood cohesion.

The extent to which a relationship existed between selected environmental and population parameters and annual production in a population of spruce grouse (Dendragapus canadensis franklinii) was investigated through correlation analysis of data spanning 16 years. Production of young grouse varied between 0.0 and 1.4 young, aged 4 or more weeks, per resident female over the period of this study. There was no evidence that differences in annual productivity were related to variation (maximum of 17 days) in the onset of reproduction, a function of spring temperatures. Nevertheless, weather conditions during incubation and the immediate posthatch period did exhibit a significant correlation with productivity: cold, wet conditions during incubation were associated with years of poor productivity, whereas the same conditions during the immediate posthatch period were associated with years of good survival of young (at least to 19 days of age). Clutch and brood sizes of yearlings were smaller than those of adults; hence, production could be influenced by the proportion of the population in each age category. An inverse relationship between the density of resident females in spring and their annual production, believed to be important in this population, was reexamined with data from an additional 6 years. The relationship, although still inverse, was no longer significant.

The blood parasites in blue grouse (Dendragapus obscurus (Say, 1823)) from Vancouver Island, British Columbia were studied during the summers of 1972 through 1975. Data from 1707 birds of three age-classes indicated that infections of Leucocytozoon bonasae occurred more often (79%) than Trypanosoma avium (54%), Haemoproteus mansoni (42%), or microfilariae (37%). Concurrent associations of these taxa were more common (77%) than single species infections. Frequencies of multiple species infections did not fit expected probabilities, indicating that multiple associations are not derived independently.Young grouse acquire L. bonasae and H. mansoni by middle to late June, 2–3 weeks after hatching. Infections of T. avium and microfilariae appeared 4 and 5–9 weeks after hatch, respectively. Leucocytozoon and Haemoproteus had two transmission periods which varied seasonally among years, but which had similar within-year patterns. Simulium aureum was incriminated as a vector of L. bonasae, but attempts at experimental transmission were not made. The utilization of common species of vectors by several taxa of parasites is postulated. Competitive exclusion does not appear to exist for this species assemblage.

The demographic characteristics of an increasing population of blue grouse were studied from 1968 to 1971. Increasing populations of grouse had high reproductive rates and slightly higher than average mortality rates among females as compared to stable populations.

Parameters of digestion and energetics of free-living grouse were plotted against body mass to determine whether a general relationship exists between quantitative food intake, digestibility, and energy demands of individuals of different sizes, and to clarify the relationship between chemical composition of the diet and individual energetic demands of different species. Regression analysis showed a positive correlation between each of the parameters (except dry mass of caecal faeces) and body mass, reflecting a relationship between differences in chemical composition of the browse in the diets and its digestibility. Modelling intermediary metabolism in three grouse species revealed that about 50% of metabolizable energy originated from carbohydrate oxidation; the rest was shared among fiber (9–35%), protein (9–14%), and crude fat (12–25%). The more nitrogen in the diet, the higher were estimates of total digestibility, as well as those of fiber and fat. A generalized model of nitrogen demands of individuals is proposed and predictions from the model are compared with particular determinations based upon actual data from different species. The digestibility of natural grouse diets, and consequently available energy, is essentially dependent upon the concentration of protein in the diet. This suggests that it is necessary for grouse to exceed the minimal physiological level of nitrogen intake, not only to create reserves, but also to function effectively in the presumed need to detoxify and digest those fractions of the diet that are difficult to absorb.

Analyses are given for several parameters in the production of juvenile spruce grouse in a local population in southwest Alberta (Canachites canadensis franklinii), 1970–1975, and in northeast New Brunswick (C. c. canace), 1975–1980. Canachites c. canace exhibited greater clutch size, nest success, proportion of females with broods and production of juveniles. Hatchability of eggs, average brood sizes, and mortality rates of juveniles were similar. Differential nest success appeared to be a primary influence on the difference in production of juveniles. In autumn, canace exhibited a substantial net reduction in juveniles as a consequence of dispersal, but not franklinii. Densities of juveniles in winter were similar. Speculation is provided about the differences in production and their association with other aspects of life history, notably the quality of juvenile stock.

Forty wild-trapped white-tailed ptarmigan (Lagopus leucurus) were released onto Pike's Peak, Colorado, in June (six mated pairs) and September (9 males, 7 females, 12 juveniles) 1975. Numbers declined 37.5% by the first spring (1976) after the introduction. Spring densities gradually recovered, increasing from 3.4 grouse per 100 ha of breeding habitat in 1976 to 8.4 in 1979, then declined to 7.4 in 1980. Mean distance of territories from the release area increased only 0.86 km (p = 0.44) from 1976 to 1980, reflecting a slow process of expansion. Reproduction was documented in all years including 1975. Survival of released birds until 1976 was 93.3% for males, 46.1% for females, and 33.3% for juveniles. Time of release did not influence survival. Average annual survival (1976–1980) was 64.9% for adult males, 60.3% for adult females, and 43.1% for juveniles. Yearlings comprised 39.7% (range, 20.0 to 54.9%) of all birds (N = 219) identified exclusive of juveniles. Of the 219 birds identified, 137 (62.6%) were males.