Blue Grouse Research Articles

Polycyclic aromatic hydrocarbons and polychlorinated biphenyls in soils and atmosphere of Western Canadian mountains: The role of source proximity, precipitation, forest cover and mountain cold-trapping

Abstract Soil was sampled and XAD-2 based passive air samplers were deployed for one year at several locations on four mountains and a mountain pass in British Columbia (BC), Canada. The mountains, ranging between ca. 1100–1500 m in altitude, varied in their proximity to likely sources of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). Considered mountain-by-mountain, proximity to sources determines the concentrations of PCBs: Grouse Mountain, immediately to the North of Vancouver, had the highest PCB concentrations in both atmospheric gas phase and soil, while three other mountains in southern BC had levels approximately a factor of three lower. PCB concentrations along the Chilkoot Trail in remote Northern BC were more than an order of magnitude lower. While Grouse Mountain also had the highest PAH concentrations, gas phase concentrations of PAHs elsewhere were only slightly lower and varied little between the different mountains. Soil concentrations of PAHs were highly elevated on urban Grouse Mountain and lowest on Blue Grouse Mountain, which stands out by having the driest climate. On a site-by-site basis, PCB concentrations in the atmospheric gas phase decreased with increasing elevation but show indication of upslope enrichment in the soils of three of the mountains. These include the most urban mountain and two rural mountains, which have more precipitation and forest coverage than the remaining two mountains. There was no difference between congeners in the extent of upslope enrichment, indicating that the temperature gradient along the mountains was not sufficiently large to cause fractionation. Atmospheric gas phase and soil concentrations of PAHs on a mountain decrease with distance from likely sources. Although sources of PAHs are too widespread to observe any trends of mountain cold-trapping, PCBs are clearly experiencing cold-trapping in Western Canadian mountains.

Individual heterogeneity and effects of harvest on greater sage‐grouse populations

ABSTRACTThe influence of harvest on wild populations has been the focus of substantial debate, and has widespread implications for the management of wild populations. Traditional views of harvest are based on density‐dependent responses of populations to harvest. However, alternate mechanisms can and do induce compensation (e.g., individual heterogeneity). Selective harvest of successful females and their offspring is thought to occur in some grouse populations (e.g., blue grouse [Dendragapus spp.], greater sage‐grouse [Centrocercus urophasianus]), and delaying harvest within a season has been proposed as a viable strategy to overcome this type of selective harvest. However, a recent examination regarding the effects of harvest on greater sage‐grouse strongly criticized the recommendation of delayed harvest. Herein, we address the criticism of the delayed harvest strategy and provide an examination of projecting the effects of harvest in the face of individual heterogeneity using deterministic projection models. We demonstrate that under proportional harvesting strategies, given a fixed harvest rate, early additive harvest does not have a larger effect on the population than additive harvest later in the season. Moreover, we show that when higher quality individuals (i.e., individuals with higher survival and reproductive rates) are more susceptible to harvest, individual heterogeneity in harvest effects will induce depensatory dynamics when density‐dependent effects are only additive. Conversely, even when density‐dependent effects are additive, if lower quality individuals are more susceptible to harvest, heterogeneity will induce partial compensation. Reducing the selectivity of harvest on higher quality individuals (i.e., shifting harvest onto lower quality groups) could reduce the risk of artificial selection and induce partial compensation. Therefore, we recommend managers consider the spatiotemporal patterns of populations and time harvest to maximize the heterogeneity tradeoff between higher and lower quality individuals. © 2017 The Wildlife Society.

Trace metal depositional patterns from an open pit mining activity as revealed by archived avian gizzard contents

Archived samples of blue grouse ( Dendragapus obscurus) gizzard contents, inclusive of grit, collected yearly between 1959 and 1970 were analyzed for cadmium, lead, zinc, and copper content. Approximately halfway through the 12-year sampling period, an open-pit copper mine began activities, then ceased operations 2 years later. Thus the archived samples provided a unique opportunity to determine if avian gizzard contents, inclusive of grit, could reveal patterns in the anthropogenic deposition of trace metals associated with mining activities. Gizzard concentrations of cadmium and copper strongly coincided with the onset of opening and the closing of the pit mining activity. Gizzard zinc and lead demonstrated significant among year variation; however, maximum concentrations did not correlate to mining activity. The archived gizzard contents did provide a useful tool for documenting trends in metal depositional patterns related to an anthropogenic activity. Further, blue grouse ingesting grit particles during the time of active mining activity would have been exposed to toxicologically significant levels of cadmium. Gizzard lead concentrations were also of toxicological significance but not related to mining activity. This type of “pulse” toxic metal exposure as a consequence of open-pit mining activity would not necessarily have been revealed through a “snap-shot” of soil, plant or avian tissue trace metal analysis post-mining activity.

Winter Prey Selection of Canada Lynx in Northwestern Montana

ABSTRACT The roles that diet and prey abundance play in habitat selection of Canada lynx (Lynx canadensis) in the contiguous United States is poorly understood. From 1998–2002, we back‐tracked radiocollared lynx (6 F, 9 M) for a distance of 582 km and we located 86 kills in northwestern Montana, USA. Lynx preyed on 7 species that included blue grouse (Dendragapus obscurus), spruce grouse (Canachites canadensis), northern flying squirrel (Glaucomys sabrinus), red squirrel (Tamiasciurus hudsonicus), snowshoe hare (Lepus americanus), least weasel (Mustela nivalis), and white‐tailed deer (Odocoileus virginianus). Snowshoe hares (69 kills) accounted for 96% (4‐yr average, range = 94–99%) of prey biomass during the sample period. Red squirrels were the second‐most‐common prey (11 kills), but they only provided 2% biomass of the winter diet. Red squirrels contributed little to the lynx diet despite low hare densities. A logistic regression model of snowshoe hare, red squirrel, and grouse abundance, as indexed by the number of track crossings of use and available lynx back‐tracks, was a significant (Wald statistic = 19.03, df = 3, P < 0.001) predictor of habitat use. As we expected, lynx (P < 0.001) selected use‐areas with higher snowshoe hare abundance compared to random expectation. However, the red squirrel index had a weak (P = 0.087) negative relationship to lynx use, and grouse was nonsignificant (P = 0.432). Our results indicate that lynx in western Montana prey almost exclusively on snowshoe hares during the winter with little use of alternative prey. Thus, reductions in horizontal cover for hares would degrade lynx habitat.

"Blue Grouse: Their Biology and Natural History" by Fred C. Zwickel, and James F. Bendell. 2004. [book review

"Blue Grouse: Their Biology and Natural History" by Fred C. Zwickel, and James F. Bendell. 2004. [book review

Grouse of the Lewis and Clark Expedition, 1803 to 1806

Members of the Lewis and Clark expedition produced written descriptions of many species of wildlife, including 6 species of grouse. We reviewed the accounts of 83 grouse observations, plus summary descriptions and indirect references to grouse by Meriwether Lewis, William Clark, and 3 of their sergeants. We then assigned them to species based on described characteristics, known distributions, habitat, behavior, and/or other written clues. Fifty-nine (71%) observations were con- sidered relatively unambiguous as to identity because of a bird's morphology and appearanceJ a descriptive name, a non-overlapping range, and/or other clues. These included greaterprairie-chick- ens (Tympanuchus cupido), sharp-tailed grouse (1: phasianellus), greater sage-grouse (Centrocercus uro- phasianus), blue grouse (Dendragrpus obscurus), spruce grouse (Falcipennis canadensis), and ruffed grouse (Bonasa umbellus). Other observations were assigned to 'possible' species based on available evidence. Our evaluation of Lewis's and Clark's written descriptions differed in some cases from earlier reviews. Most notable differences involved blue, spruce, and ruffed grouse and we offer sug- gestions for changes. We also used journal records to compare pre-settlement (by Euro-Americans) distributions of grouse as indicated by the journal records with those today and to speculate on changes in abundance. Greatest changes have occurred in distributions and abundances of the 3 prairie grouse, species whose habitats have been most impacted by settlement. Other highlights of the expedition include the 1st written descriptions of blue grouse and greater sage-grouse and of undescribed subspecies of sharp-tailed, spruce, and ruffed grouse.

Microclimatic characteristics of blue grouse Dendragapus obscurus roost‐sites: influence on energy expenditure

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.

Food Habits and Preferences of Blue Grouse during Winter

We determined winter food habits of blue grouse (Dendragapus obscurus) by observing radiomarked birds in the wild over 2 years. We used captive blue grouse to assess preference for, and voluntary intake and metabolizable energy (ME) of, Douglas-fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta), limber pine (P. flexilis, preference only), subalpine fir (Abies lasiocarpa), and Engelmann spruce (Picea engelmannii). Most (91%) feeding by wild birds was in Douglas-fir or lodgepole pine. Feeding was concentrated on younger needles in the upper canopy of older trees. Limber pine was browsed by some birds, but feeding was rarely observed in subalpine fir or Engelmann spruce. Preference rankings closely paralleled ME values: Douglas-fir (ME = 1.80 kcals/g) = lodgepole pine (1.72 kcals/g) > limber pine (ME not calculated) > subalpine fir (1.52 kcals/g) = Engelmann spruce (1.15 kcals/g). Captive birds preferred needles from mature Douglas-fir to needles from young trees, and 1-2 year-old needles of Douglas-fir to older needles. This selection was consistent with a strategy of maximizing intake of metabolizable energy while meeting nitrogen requirements. Although blue grouse preferred to eat needles of species from which they extracted the most energy, these needles were not clearly superior by conventional nutritional analyses.

DNA Fingerprinting Reveals Monogamy in the Bushtit, a Cooperatively Breeding Species

SAYCE, J. R., AND G. L. HuNT, JR. 1987. Sex ratios of prefledging Western Gulls. Auk 104:33-37. SHKLAREVITCH, F. N., AND V. F. NIKULIN. 1979. Sex determination of day-old ducklings in the field and sex ratios of broods in the Common Eider. Pages 106-112 in The ecology and morphology of eider ducks in the USSR (A. A. Kischinski, Ed.). Publ. House Nauka, Moscow [in Russian]. SNEDECOR, G. W., AND W. G. COCHRAN. 1980. Statistical methods, 7th ed. Iowa State Univ. Press, Ames. SOKAL, R. R., AND F. J. ROHLF. 1995. Biometry: The principles and practice of statistics in biological research, 3rd ed. W. H. Freeman and Co., New York. SowLs, L. K. 1955. Prairie ducks: A study of their behavior, ecology and management. Stackpole Books, Harrisburg, Pennsylvania. SWENNEN, C., P. DuIvEN, AND L. A. REYRINK. 1979. Notes on the sex ratio in the Common Eider, Somateria mollissima (L). Ardea 67:54-61. TRIVEs, R. L., AND D. E. WILLARD. 1973. Natural selection of parental ability to vary the sex ratio of offspring. Science 179:90-92. WEATHERHEAD, P. J. 1983. Secondary sex ratio adjustment in the Red-winged Blackbird (Agelaius phoeniceus). Behav. Ecol. Sociobiol. 12:57-61. WEATHERHAD, P. J. 1985. Sex ratios of Red-winged Blackbirds by egg size and laying sequence. Auk 102:298-304. WELLER, M. W. 1965. Chronology of pair formation in some Nearctic Aythya (Anatidae). Auk 82:227235. ZWIcKEL, F. C., AND J. F. BENDELL. 1967. Early mortality and the regulation of numbers in Blue Grouse. Can. J. Zool. 45:817-851.

Phylogenetic Relationships among North American Grouse Inferred from Restriction Endonuclease Analysis of Mitochondrial DNA

Systematic relationships among North American grouse and ptarmigans (Tetraoninae) are not well defined because traditional classifications were based on morphological and behavioral characters with limited taxonomic utility. Restriction enzyme analysis of mitochondrial DNA (mtDNA) was used to generate a phylogeny for North American tetraonines that was then utilized to test previous phylogenetic hypotheses for the group and to examine the origin and evolution of complex reproductive behaviors and morphological features characteristic of grouse and ptarmigan species. Nucleotide sequence divergence among congeneric species derived from mtDNA restriction fragment patterns varied extensively, ranging from 0.28% in prairie grouse (Tympanuchus) to 4.06% among ptarmigans (Lagopus) and 10.15% between Blue Grouse (Dendragapus obscurus) and Spruce Grouse (D. canadensis). Using the Northern Bobwhite (Colinus virginianus) as an outgroup, the molecular phylogeny partitioned species into three primary groups: (1) Tympanuchus; (2) Lagopus, Dendragapus obscurus, and Tetrao urogallus (the European Capercaillie); and (3) the Ruffed Grouse (Bonasa umbellus), Dendragapus canadensis, and Sage Grouse (Centrocercus urophasianus). Prairie grouse were genetically distinct from other grouse species, but a polyphyletic distribution of haplotypes and limited mtDNA differentiation within Tympanuchus suggest that divergence among the prairie grouse occurred very recently. Within Lagopus, the Willow (L. lagopus) and Rock (L. mutus) Ptarmigans were more closely related to each other than either was to the White-tailed Ptarmigan (L. leucurus). Dendragapus canadensis grouped with Bonasa umbellus; whereas D. obscurus was allied with Lagopus and Tetrao. Thus, the genus Dendragapus as currently constructed is polyphyletic (i.e., D. canadensis and D. obscurus have had separate evolutionary histories) and the morphological similarities between the two species may be attributable to convergent adaptation to coniferous forest. We inferred from the molecular phylogeny that the complex reproductive systems in tetraonines have arisen independently and that corresponding morphological and behavioral specializations may reflect parallel evolutionary trends.

Blood parasites of blue grouse: variation in prevalence and patterns of interspecific association.

Blood parasites of blue grouse (Dendragapus obscurus) were sampled and the factors responsible for variation in prevalence of blood parasites, and patterns of association among parasite species, were investigated. Five genera of haematozoa were surveyed including four protozoans (Haemoproteus, Leucocytozoon, Plasmodium, and Trypanosoma) and a nematode (Splendidofilaria). Prevalence of blood parasites varied significantly between years; sexes differed in number of parasite species in one of two years. Both positive and negative 'overall' associations among all parasites were found when variance-ratio tests were used indicating that blood parasites often were not independent of one another. In general, Leucocytozoon and Trypanosoma often co-occurred; the strongest associations between these two parasites appeared in samples of hosts most heavily infected by other parasites. Negative associations between parasite species always involved Haemoproteus. Associations between pairs of species did not account wholly for overall patterns of associations within the parasite assemblage. Studies of associations within blood parasite assemblages are important for understanding the ecology of haemotropic infections and for clucidating the need for multi-parasite models of parasite-host interactions.

Field metabolic rate of blue grouse during winter

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 < 0.05) from captive grouse (0.944 ± 0.058 L CO2∙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.

Variations in courtship activity among male blue grouse: do some males breed more than others?

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.

Partial Migration in a Population of Greater Prairie-Chickens in Northeastern Colorado

-Seasonal movements of radio-marked Greater Prairie-Chickens (Tympanuchus cupido) were examined in northeastern Colorado during 1986-1989. Many birds migrated between breeding and winter areas; all appeared to display fidelity to both breeding and winter sites. The average date of migration from winter to breeding areas was 20 February for males and 27 March for females. The average date of migration from breeding to winter areas was 4 July for females and 28 July for males. Much of the variability in timing of migration from breeding areas for females was related to brood status; average date of migration was 10 June for females without broods and 26 August for females with broods. Average migration distance between winter and breeding ranges differed significantly by sex: 9.2 km for females and 2.7 km for males. When migration samples were expanded to include distances between breeding and late summer ranges (as suggested by timing of movements), females migrated an average distance of 10.6 km, while males migrated 2.9 km. Seasonal movements of Greater Prairie-Chickens appear to represent partial migration with both obligatory and facultative components. Received 3 June 1991, accepted 23 February 1992. MIGRATION has been defined as a regular round trip within life-span of the individual (Sinclair 1983:241), while patterns of migration have been categorized as annual, partial, or differential (Terrill and Able 1988). Species of Tetraoninae are particularly variable with respect to migration patterns. While some species such as Willow and Rock ptarmigan (Lagopus lagopus and L. mutus) may be annual migrants in certain regions (Weeden 1964, Irving et al. 1967), most are considered either nonmigrants or partial migrants with only some individuals migrating. However, extensive research on movements of Blue Grouse (Dendragapus obscurus; Wing 1947, Mussehl 1960, Zwickel et al. 1968), Spruce Grouse (D. canadensis; Herzog and Keppie 1980, Schroeder 1985), White-tailed Ptarmigan (Lagopus leucurus; Hoffman and Braun 1975), and Common Capercaillie (Tetrao urogallus; Rolstad 1989) indicate that patterns of partial migration may be the rule rather than the exception, particularly among females. Explanations for partial migration include seasonal and/or sexual differences in habitat selection, and dispersal differences due to ag3 Present address: Washington Department of Wildlife, P.O. Box 1077, Bridgeport, Washington 98813, USA. gressive interactions, breeding success, and/or heritability (Lack 1944, Biebach 1983, Smith and Nilsson 1987). For example, Blue Grouse migration has been attributed to elevational and/ or seasonal differences in habitat selection (Wing 1947, Mussehl 1960, Zwickel et al. 1968), and Spruce Grouse migration appears to be related to fidelity to specific winter and breeding areas, and to variability in dispersal movements during their first spring (Herzog and Keppie 1980, Schroeder 1985, 1988). Despite similarities in patterns of movement for Blue Grouse, Spruce Grouse, White-tailed Ptarmigan, and Common Capercaillie, possible explanations for movement have not been thoroughly examined in other species of Tetraoninae. Greater Prairie-Chickens (Tympanuchus cupido) are among the most mobile of the species in the Tetraoninae, with seasonal movements up to 170 km (Hamerstrom and Hamerstrom 1949). Early reports indicated that Greater Prairie-Chicken movements were particularly extensive among females and typically related to seasonal differences in habitat selection (Schmidt 1936, Hamerstrom and Hamerstrom 1949) and regional food availability, such as the abundance of acorns (Quercus spp.; Cooke 1888, Gross 1930, Leopold 1931). However, Gross (1930) suggested that introduction of corn throughout the range of Greater Prairie-Chick-

Winter energy requirements of blue grouse

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.

Post-Nesting Movements of Female Blue Grouse

Four radio-marked adult female blue grouse, Dendragapus obscurus, had brood ranges 1 km to more open brood ranges. Cumulative movements of 7 of 20 brood hens exceeded 1 km in the first week post-hatch; two adults remained within 0.5 km of their nests but five yearlings moved beyond that. Mean daily movements of brood hens in the first week post-hatch were 0.14 and 0.11 km/day for yearling and adult females, respectively. Mean bimonthly sizes of home ranges of brood hens were relatively constant throughout summer but mean cumulative sizes increased steadily. Eleven of 30 hens moved 1 to 3.2 km from their nest sites immediately after losing their clutches or broods; 10 entered dense forest. Post-nesting home ranges of 12 of 28 broodless hens were >0.5 km from their nests. Mean sizes of pre-migratory bimonthly home ranges of most broodless females remained constant following loss of eggs or chicks and were the same size as those of brood hens; mean cumulative sizes increased steadily until departure from breeding range. Hens with broods used more open vegetative cover than those without broods and remained on breeding range until late August or early September. Hens without broods remained on breeding range from 3-54 days after loss of nests or chicks and, on average, left breeding range about one month before hens with broods. Movements of brood and broodless hens from breeding range (postbreeding migration) were largely unidirectional and began with a sudden move toward upland forest. Migratory movements ranged from 1-1.8 km/day. We suggest that: 1) some yearling females may nest in sub-optimal habitats that not adjacent to acceptable brood ranges because of saturation of optimal habitats by adults and other yearlings, and 2) that broods may remain on breeding ranges longer than broodless females because of resources required by chicks. Hannon et al. (1982) provided evidence that most yearling female blue grouse, Dendragapus obscurus, settle for nesting only after most adults laying or incubating eggs. They suggested that restriction of movements by nesting adult females tends to reduce interactions between the two age-classes and might explain settling patterns among yearling females. We studied post-nesting movements of radio-marked female D. obscurus with and without broods to examine the relationship between preand post-nesting home ranges. The principal question we asked was: are sites settled by females in spring chosen to provide brood range for chicks? This question bears on a suggestion of Sopuck (1979) that adults may be excluding some yearlings from prime nesting habitat. Secondary objectives were to compare post-nesting movements, post-nesting use of cover, and migration from breeding range of brood hens to those of broodless hens, for these comparisons might provide clues as to needs of hens with chicks. Studies were conducted in the springs and summers of 1976 and 1977 in the foothills and nearby mountains of east-central Vancouver Island, British Columbia.

Blood Parasites of Blue Grouse (Dendragapus Obscurus) In Western North America

Three hundred thirty-three blue grouse (Dendragapus obscurus) were examined for blood parasites from 11 sites: southern Yukon Territory, southeast coastal Alaska, northern and central interior British Columbia, south coastal British Columbia, northcentral Washington, southcentral Oregon, northwestern California, eastcentral Nevada, northwestern Colorado, and westcentral Montana. Three species of protozoan parasites (Leucocytozoon lovati, Haemoproteus mansoni, Trypanosoma avium) and a splendidofilariid nematode (Microfilaria sp. B) were found in nearly all locations. Prevalence levels were consistently high for L. lovati (92%). The other hematozoa were found less frequently (H. mansoni 29%; T. avium 46%; and microfilaria 29%). The range of these parasites in blue grouse was extended to a more northern (Yukon Territory) and more southern distribution (Nevada than previously reported. Ranges were also extended to blue grouse populations in Alaska, Washington, Oregon and California.

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

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.

Winter Use of Douglas-Fir Forests by Blue Grouse in Colorado

We studied winter use of Douglas-fir (Pseudotsuga menziesii) forests by blue grouse (Dendragapus obscurus) from 1981 to 1983 at 2 study areas in northcentral Colorado. Comparisons of used and available stands indicated grouse were concentrated spatially, but there were no consistent differences related to basal area of tree species, conifer stem densities, and topography that were common to both areas. Blue grouse used dense (2,000 stems/ha) second growth (40-75 yr old), open to dense (200-1,900 stems/ha) mature (100200 yr old), and open ( 250 yr old) stands at elevations >300 m, but also used early successional stages (520 yr old) at elevations <300 m more than expected. Hines (1987) suggested that blue grouse use a broader range of conifer habitats in winter than previously reported. Zwickel and Bendell (1972) speculated that winter habitat and food probably did not limit populations because blue grouse disperse over a wide area of conifer forests in winter after leaving the breeding range, and winter food appears abundant. This hypothesis implies that blue grouse either use a wide range of available conifer habitats or a few specific conifer types that are widespread. For species such as the blue grouse that frequently occupy different seasonal habitats, knowledge of year-round habitat requirements is imperative for formulating sound management strategies. Schroeder (1984) identified a lack of quantitative information on winter habitat use. Accordingly, we investigated winter use of Douglas-fir forests by blue grouse in Colorado with the following objectives: (1) to compare use and availability among conifer stands to determine if preferential use was related to topography, species composition, and stand structure; (2) to compare tree species and diameter classes used with availability within stands; and (3) to compare habitats used by males and females. A. L. Cade, M. W. Crosby, J. J. Jeanson, and K. A. Medve provided field assistance. The manuscript benefited from reviews by A. E. Anderson, M. J. Armbruster, D. C. Bowden, C. E. Braun, R. C. Kufeld, R. T. Reynolds, R. A. Ryder, and D. F. Stauffer. Special thanks are extended to the many landowners who allowed us access to lands under their control. This is a contribution of the Colorado Division of Wildlife, Federal Aid to Wildlife Restoration Project

Influence of Transmission Period on Primary and Relapse Patterns of Infection of Leucocytozoon spp. and Haemoproteus mansoni

Leucocytozoon sp., L. lovati and Haemoproteus mansoni infections in captive blue grouse (Dendragapus obscurus) were monitored weekly throughout primary and relapse periods. Chicks developed primary infections with L. lovati and Leucocytozoon sp. during 5- 9 wk of natural exposure, whereas H. mansoni was transmitted during a 2-3-wk period. Relapse infections of Leucocytozoon sp. and L. lovati in wild blue grouse had constant monthly prevalences (percent infected) and intensities (mean number of parasites). In contrast, prev- alence and intensity increased throughout the relapse period for H. mansoni. The patent period in infrapopulations (within one host) of H. mansoni was 5-11 wk for primary, and 11-26 wk for relapse infections. Likewise, peak intensities appeared 1-4 wk after the start of patency for primary and 5-11 wk for relapse infections. No differences were detected in the Leucocytozoon spp. Precise timing and peak intensity was selected for in H. mansoni which had a short transmission period, but not in Leucocytozoon with long transmission periods. Gametocyte production occurs for a longer period during relapse than during the primary period. This satisfies constraints imposed by a pulse vector on parasite transmission to vertebrate hosts. A model is proposed to explain the evolution of the complex intensity patterns observed in H. mansoni.