Blue Grouse Research Articles

Why do grouse have ceca? A test of the fiber digestion theory.

Two predictions deduced from the theory that grouse ceca function primarily to provide a suitable environment for the fermentation of plant fiber were tested. Digestion of neutral detergent fiber in conifer needles by blue grouse (Dendragapus obscurus) varied from 7.5 to 17.3% across tree species, but, contrary to prediction, the energy potentially derivable from this fiber digestion was insufficient to make ceca energetically profitable. Variation in digestibility of fiber among birds and across species was caused by differential accessibility of fiber to the ceca as essentially all (average, 96.8%) fiber entering the ceca was digested. An allometric analysis of grouse gut lengths suggested, and a correlation analysis confirmed, that cecal lengths among species of grouse decrease in length as dietary fiber increases, also soluble and suspended particulate food components from insoluble. Ceca do act as fermentative and absorptive reservoirs for fiber, but also (and predominantly) for urine and cell soluble or suspended components previously undigested because of high rates of passage. I suggest that the adaptive significance of this strategy is to maximize the rate at which energy is obtained from poor quality foods.

Autumn Habitat of Capercaillie in Southeastern Norway

I studied autumn habitat use by radio-marked capercaillie (Tetrao urogallus) in a coniferous forest in southeastern Norway, from September to November 1984-86. I derived use of elevation, successional stage, edge, vegetation type, tree and shrub cover, and tree height by extrapolating 876 locations of 26 males and 20 females from a habitat map. Both sexes preferred old, spruce-dominated forests. Within old forests, males preferred forest interiors, and within clearcuts males preferred edges of old forests. Males were found at higher elevations than females. Commercial forestry affects capercaillie autumn habitats adversely by extensive cutting of old, bilberry (Vaccinium myrtillus)-rich natural forests, and by producing dense, managed forest stands. J. WILDL. MANAGE. 52(4):747-753 Capercaillie inhabit boreal coniferous forests in the palearctic region. When the ground is snow-covered, birds feed on pine needles; the distribution of capercaillie along the northern part of their range is almost congruent with Scots pine (Pinus sylvestris) (Seiskari 1962:46). During winter and early spring, capercaillie prefer old pine forests with thick branches and open canopy to allow birds to feed in trees and fly between them (Gjerde et al. 1985, Klaus et al. 1985, Rolstad and Wegge 1988). In summer, capercaillie consume a great variety of plant species (Semenov-Tjan-Sanskij 1960), and their affinity for old forests is less pronounced (Marcstrim et al. 1982, Rolstad et al. 1988). During the last 20-30 years, capercaillie have declined markedly throughout their range, presumably because of habitat destruction and excessive cutting of old, natural forests (Marcstrim 1979, Moss et al. 1979, Klaus 1982). Other woodland grouse (blue grouse [Dendragapus obscurus] and spruce grouse [D. canadensis]) exhibit distinct seasonal changes in habitat use (Pietz and Tester 1982, Bendell and Zwickel 1985). Capercaillie habitat use is well documented for most of the year (Rolstad and Wegge 1988), except for autumn (Unander 1980, Toverud 1984). My objective was to determine capercaillie habitat use and old forest affinity during

Nesting parameters in a high density, declining population of blue grouse

Of four nesting parameters (clutch size, egg fertility, egg hatchability, and nesting success) in a population of blue grouse, Dendragapus obscurus fuliginosus, at Hardwicke Island, British Columbia, only clutch size differed between yearling and adult females. There was no difference among years for any of the parameters considered. This population declined from very high to moderate density during the studies reported here, and clutch size, egg fertility, and hatchability were significantly lower than reported for a more stable population (Comox Burn) in the same general region. Nesting success at Hardwicke Island, however, was higher than at Comox Burn. Collectively, the parameters examined do not, by themselves, explain the observed decline. Nevertheless, they suggest that the population at Hardwicke Island differed from that at Comox Burn in some fundamental aspects of reproduction that may be symptomatic of other factors possibly involved in its decline, e.g., the survival of chicks.

Length of Incubation Period of Blue Grouse

Length of Incubation Period of Blue Grouse

Populations of Leucocytozoon gametocytes in blue grouse (Dendragapus obscurus) from Hardwicke Island, British Columbia.

Population dynamics of round and elongate gametocytes of Leucocytozoon in wild and captive blue grouse (Dendragapus obscurus (Say)) from Hardwicke Island, British Columbia, were studied from 1980 to 1982. Blue grouse chicks were sampled weekly throughout each transmission season. Three patterns in the type of gametocyte produced during primary infection were observed in naturally infected captive and wild blue grouse chicks. Such variation in the expression of the gametocyte stage within a single host population suggests a different interpretation than has been previously reported for species of Leucocytozoon. The data from the primary patterns and profiles coupled with reexposure data and the asynchronous appearance of round and elongate gametocytes can be best interpreted as infection with two concurrent species of Leucocytozoon in blue grouse. More detailed research on the life cycle is necessary to confirm if two species of Leucocytozoon exist in blue grouse.

Spacing Behavior and Population Regulation in Female Blue Grouse

Spacing Behavior and Population Regulation in Female Blue Grouse

Winter Habitat Relationships of Blue Grouse on Hardwicke Island, British Columbia

Winter Habitat Relationships of Blue Grouse on Hardwicke Island, British Columbia

Pyramiding Behavior in the Inca Dove: Adaptive Aspects of Day-Night Differences

ENG, R. L. 1963. Observations on the breeding biology of male Sage Grouse. J. Wildl. Manage. 27: 841-846. HANNON, S. J., B. R. SIMARD, F. C. ZWICKEL, AND J. F. BENDELL. 1979. Differences in the gonadal cycles of adult and yearling Blue Grouse. Can. J. Zool. 57:1283-1289. JAMIESON, I. G. 1985. Behavior of yearling male Blue Grouse and its relation to delayed breeding. Wilson Bull. 97:71-77. JAMIESON, I. G., AND F. C. ZWICKEL. 1983. Spatial patterns of yearling male Blue Grouse and their relation to recruitment into the breeding population. Auk 100:653-657. LEWIS, R. A. 1981. Characteristics of persistent and transient territorial sites of male Blue Grouse. J. Wildl. Manage. 45:1048-1051. LEWIS, R.A. 1984a. Non-territorial adult males and breeding densities of Blue Grouse. Wilson Bull. 96:723-725. LEWIS, R. A. 1984b. Survival, behavior, use of territories, and breeding densities of male Blue Grouse in coastal British Columbia. Ph.D.diss., Univ. Alberta, Edmonton. LEWIS, R. A. 1985. Use of space by territorial male Blue Grouse. Wilson Bull. 97:97-101. LEWIS, R. A., AND F. C. ZWICKEL. 1980. Removal and replacement of male Blue Grouse on persistent and transient territorial sites. Can. J. Zool. 58:1417-1423. LEWIS, R. A., AND F. C. ZWICKEL. 1981. Differential use of territorial sites by male Blue Grouse. Condor 83:171-176. LEWIS, R. A., AND F. C. ZWICKEL. 1982. Survival and delayed breeding in male Blue Grouse. Can. J. Zool. 60:1881-1884. McNICHOLL, M. K. 1978. Behaviour and social orga ization in a population of Blue Grouse on Vancouver Island. Ph.D.diss., Univ. Alberta, Edmonton.

Use of early successional, midsuccessional, and old-growth forests by breeding blue grouse (Dendragapus obscurus fuliginosus) on Hardwicke Island, British Columbia

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.

Aggressiveness, incidence of singing, and territory quality of male blue grouse

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.

Survival and Reproduction of Dispersing Blue Grouse

Dispersal in a declining population of Blue Grouse (Dendragapus obscurus) was studied over four years on Hardwicke Island, British Columbia, Canada, by radio-tracking 66 individuals and reobserving or recapturing 126 banded individuals. On a 464-ha main study area, numbers of territorial males decreased from 152 to 94, breeding females from 276 to 113, and young grouse alive in late summer from 847 to 224 during the period of study. Despite this, dispersal distances did not vary between years and bore no clear relationship with adult densities in spring or density of juveniles in the previous fall. Rates of survival and reproduction for long-dispersers (grouse moving greater than the median dispersal distance) and short dispersers (grouse moving less than the median dispersal distance) were similar. Similar results were noted for grouse that left the study area (dispersers) and those that remained on the study area (non-dispersers). Overall, there was little evidence that dispersers fared poorly or that dispersal was greatly influenced by population density.

A guide to the literature on aggressive behavior

A guide to the literature on aggressive behavior

Influence of Radio Packages on Young Blue Grouse

Effet du radio-marquage sur le comportement, le succes reproducteur et la survie en comparaison avec des oiseaux non equipes

Blue Grouse—Effects on, and Influences of, a Changing Forest

Blue grouse (Dendragapus obscurus) may increase spectacularly in lowland Pacific coast forest that has been logged by clear-cutting. Locally, they may be used heavily by hunters, and more subtly, by nonconsumptive recreationsists. They can be sufficiently abundant to affect the survival of young conifers, the distribution of seeds and, perhaps, nutrient cycling. Blue grouse can represent a major component of the faunal biomass on a given area.Local populations of blue grouse change mainly as a result of forest management practices on lowland breeding ranges. Logging at higher elevations probably will not produce grouse in equivalent densities, and the implications of increased logging on winter range (at even higher elevations) are unknown.Current logging and silvicultural practices have both positive and negative effects on blue grouse. Newly logged lowlands are colonized rapidly by "surplus" grouse from nearby, established populations. They may persist in variable, but unpredictable, densities until forest canopy approaches 75% coverage. Populations decline due to non replacement of adults that die. Although clear-cutting often results in short-term, and occasionally large, increases in numbers, these persist for only about 25% or less of a planned rotation period. The productive period for occupancy by grouse may be shortened by early planting, planting everywhere, fertilization with urea, and by large, even-aged plantations. The productive period may be extended by delayed planting, a wider spacing within plantations, not planting sites of low timber productivity and, perhaps, by intensive thinning throughout the forest rotation, or cutting in small patches.An important key to continuous maintenance of breeding populations of blue grouse appears to be the presence of a well-developed and diverse understory. Alternatives to present clear-cutting practices that would leave a more open tree canopy would probably provide continuous production of grouse and many other species, albeit at a lower density than sometimes results from present programs. Experimental forests that can be manipulated in conjunction with long-term studies of the effects of these manipulations on wildlife are needed if we are to integrate forest - wildlife management practices fully. Keywords: blue grouse, Dendragapus obscurus, populations, clear-cut logging, silviculture, forest succession.

Ruffed and Blue Grouse Habitat Use in Southeastern Idaho

Bonasa umbellus et Dendragapus obscurus ont des habitats preferentiels differents et le chevauchement de leur niche ecologique est faible dans le sud-est de l'Idaho, en toutes saisons

Aggressive and Spacing Behavior of Female Blue Grouse

-Female Blue Grouse (Dendragapus obscurus) on Stuart Island, Washington were found to interact aggressively with female dummies in the prelaying period when a taped cackle call was played. Interactions included: tail fanning, wing dragging, everting the white patagium feathers to display a shoulder patch, head bobbing, neck stretching, jump attacking, pecking, and diving attacks. Threatening and aggressive calls included: cackling calls with inflections, a Nee-uk call, and attack and scream whinny calls. The frequency of aggressive interactions was greatest in the latter half of April, a period when hens were selecting nesting sites. The prelaying ranges of 12 hens were mostly mutually exclusive and showed a dispersed distribution relative to each other. However, there were interspaces sufficient for other grouse to nest. We suggest that aggressive behavior and mutual avoidance of females resulted in a dispersed distribution of nest sites. Such spacing should enhance the reproductive fitness of females by reducing predation rates on hens, eggs, and young. Received 24 August 1983, accepted 16 November 1984. THERE has been disagreement among biologists on whether territoriality in birds primarily served to disperse the breeding population (Lack 1966, 1968), or whether, in addition to this spacing function, it regulated numbers by excluding some individuals from securing breeding space (Wynne-Edwards 1962). Even after 20 years, the argument continues (Davies 1978, Patterson 1981, Wittenberger 1981). Recently, the territorial limitation hypothesis has been expanded to include the mutual exclusion of yearling females by other females in polygynous Blue Grouse (Dendragapus obscurus; Zwickel 1972, 1980; Hannon and Zwickel 1979). The primary evidence for surplus nonbreeding females was that, following the removal of localized females in the prelaying period, additional yearling females occupied the vacancies created (Zwickel 1972, 1980). However, this replacement does not constitute unequivocal evidence of socially induced nonbreeding in yearling females, since these females might have bred elsewhere (cf. Watson and Moss 1970). The newcomers could have shifted their ranges to improve their fitness as proposed in the Fretwell-Lucas habitat model (Fretwell and Lucas 1969). Such redistribution is consistent with theoretical considerations that animals should space themselves to reduce predation risk (Taylor 1976). The resolution of this perennial question requires documentation of the dispersion pattern of all females in a population where emigration cannot confound results. We measured aggressiveness and described the distribution of female Blue Grouse on Stuart Island, Washington during the breeding cycle in 1975 and 1976. Our hypothesis was that social interactions between females in the prelaying period resulted in mutually spaced ranges but that the spacing and ensuing social interactions did not prevent any female from nesting. Subordinate females could either nest between the ranges of other females or delay nesting until adults were egglaying and/or incubating their eggs.

Intra-Testicular Inoculation of Brugia pahangi Infective Larvae into Inbred GN Hamsters

white (Colinus virginianus) (Stabler and Kitzmiller, 1976, loc. cit.); scaled quail (Callipepla squamata) (Herman, in Campbell and Lee, 1953, loc. cit.); Gambel's quail (Callipepla gambelii) (Herman, In Campbell and Lee, 1953, loc. cit.; Stabler and Kitzmiller, 1976, loc. cit.); California quail (Callipepla californica) (Herman, In Campbell and Lee, 1953, loc. cit.); and mountain quail (Oreortyx pictus) (Stabler and Kitzmiller, 1976, loc. cit.). The tinamou, gray partridge, sage grouse, greater prairie-chickens, northern bobwhite, and mountain quail were from Colorado; the blue grouse was from Montana; the lesser prairiechicken from New Mexico and Texas; the sharptailed grouse from North Dakota and Colorado; the scaled quail were from New Mexico; the Gambel's quail from New Mexico, California, and Colorado; and the California quail from California. Plasmodium pedioecetii has thus far not been associated with morbidity. By comparison, 1 apparently healthy prairie-chicken from Texas presented a parasitemia of 189 parasitized red cells per 1,000 examined. Of 500 parasitized cells, 426 contained 1 parasite, 67 had 2, 5 had 3, and 1 each contained 4 and 5 plasmodia, respectively, or a total of 584 plasmodia in the 500 cells (Stabler, 1978, loc. cit.). This work was supported in part by the Nongame Research Program, Project N-l-R, of the Colorado Division of Wildlife. We acknowledge the encouragement of C. E. Braun and the reviews of R. W. Hoffman and M. R. Szymczak.

Density, movements, and breeding success of female blue grouse in an area of reduced male density

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.

Evidence of Aggressive Behavior in Female Blue Grouse

Description en detail de l'agressivite entre deux femelles lors d'observations sur l'ile de Hardwicke, Colombie Britannique, en 1982

Seasonal changes in spatial patterns and behavior of yearling male blue grouse on the breeding range

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.