Tympanuchus Cupido Research Articles

Active formation of mixed-species grouse leks: a role for predation in lek evolution?

Behavioural ecologists have interpreted avian leks as products of sexual selection, in which males display socially to increase their opportunities to mate. However, without invoking reproductive queuing or kin selection, this paradigm does not necessarily explain why many males that fail to mate participate in leks. An alternative solution, that males also aggregate to reduce predation, has previously lacked compelling support. We show that mixed-species leks, comprising two congeneric grouse, form when single males or small groups of one species, the greater prairie chicken Tympanuchus cupido, join leks of another, the sharp-tailed grouse T. phasianellus. We documented the process by observing lek dynamics and comparing group sizes between mixed- and single-species leks. Joining implies that prairie chickens benefit from displaying with sharp-tailed grouse. The numbers of females of each species attending a lek increased with the number of conspecific, but not heterospecific, males. This suggests that the joining of heterospecifics is unlikely to increase mating opportunities, and leaves lowered predation risk as the most likely benefit of associating with heterospecifics. Active formation of mixed-species leks therefore suggests that predation may be sufficient to drive lek formation. The benefits of participation in mixed leks may be asymmetrical because prairie chickens display more and are less vigilant than sharp-tailed grouse.

DISPLAY BY APPARENT HYBRID PRAIRIE-CHICKENS IN A ZONE OF GEOGRAPHIC OVERLAP

Abstract Greater (Tympanuchus cupido) and Lesser (T. pallidicinctus) Prairie-Chicken are thought to be historically and presently allopatric. We documented an area of approximately 250 000 ha in western Kansas characterized by leks with displaying males of both species. Display booms unlike typical Greater or Lesser Prairie-Chickens were heard and recorded at nine mixed leks. Spectrograms of these vocalizations contained elements of Greater and Lesser Prairie-Chicken booms, and comparisons suggested intermediate similarity. Males giving these booms had additional novel characters as well as novel combinations of Greater and Lesser Prairie-Chicken characters, and might represent the first case of hybridization in the wild. Despliegues de Hibridos Aparentes de Tympanuchus en una Zona de Simpatria Resumen. Aunque se ha pensado que Tympanuchus cupido y T. pallidicinctus son especies historica y actualmente alopatricas, documentamos un area de aproximadamente 250 000 ha en el oeste de Kansas que esta caracteri...

Spread and disappearance of the Greater Prairie-Chicken, Tympanuchus cupido, on the Canadian prairies and adjacent areas

Spread and disappearance of the Greater Prairie-Chicken, Tympanuchus cupido, on the Canadian prairies and adjacent areas

Conservation status and threats to grouse worldwide: an overview

A major task of the Grouse Specialist Group is to compile an IUCN/SSC Action Plan to assess threats and propose conservation actions for all grouse species worldwide. This paper provides an overview to the conservation status of and major threats to grouse based on information collected during the preparation of the Grouse Action Plan. Three species, Caucasian black grouse Tetrao mlokosiewiczi, Chinese grouse Bonasa sewerzowi and Siberian grouse Falcipennis falcipennis, are listed as globally near‐threatened or data deficient, one newly‐recognised species, Gunnison sage grouse Centrocercus minimus, is listed as globally endangered and two subspecies, Attwater's prairie chicken Tympanuchus cupido attwateri and Cantabrian capercaillie Tetrao urogallus cantabricus, qualify to be listed as globally threatened according to IUCN criteria. At a national level, 14 of the 18 species are red‐listed in at least one country. Populations at the southern edge of a species' range and in densely populated regions are most often red‐listed. Based on questionnaire results from 38 countries, habitat degradation, loss and fragmentation due to human land use activities are the major threats to grouse viability. Exploitation, predation and human disturbance were regionally felt to be critical. Major threats and their causes are reviewed based on questionnaire results and the literature. Integrating habitat preservation and human land use practices is concluded to be the major challenge to grouse conservationists worldwide.

The importance of control populations for the identification and management of genetic diversity.

A fundamental criterion for recognizing species or populations as potentially endangered is the presence/absence of genetic diversity. However, the lack of control populations in many studies of natural systems deprives one from unambiguous criteria for evaluating the genetic effects of small population size and its potential effects on fitness. In this study, I present an example of how the lack of adequate controls may lead to erroneous conclusions for understanding the role that population size may play in the preservation of genetic diversity and fitness of natural populations. The genetic analysis of a population of greater prairie chickens from Illinois, USA, between two time periods (1974-1987 and 1988-1993) in which the studied population experienced a substantial reduction in size and fitness showed no apparent associations between population size and genetic diversity. However, genetic analysis of museum specimens from early this century indicated that Illinois prairie chickens had originally higher levels of genetic diversity, which suggest the Illinois population was already bottlenecked by the 1970s. This study emphasizes the importance of using historical controls to evaluate the temporal dynamics of genetic variability in natural populations. The large number of museum collections worldwide may provide a valuable source of genetic information from past populations, particularly in species currently endangered as a result of human activities.

Looking at Birds in Different Ways

In my last column, I wrote about the relationship between birds and dinosaurs. In exploring this topic I learned a lot about extinct birds, which, in turn, made me think about those birds that are so much easier to find: the birds of the present day. There is a great deal of research being done on these creatures, and that’s what I want to write about in this column. I also want to look at some studies of birds that might not be considered scientific and yet say a lot about these creatures and our relationship with them. Much of the biological research on birds can be divided into two categories: those that use birds to explore general biological issues and those that seek to answer specific questions about bird biology. An example of the former is a 35-year study of greater prairie chickens in Illinois (Westemeier et al. 1998). While prairie chicken populations had remained relatively large and widespread in Kansas, Minnesota, Missouri and Nebraska, there was a steep decline in the Illinois population as habitats were lost; by the early 1990s there were fewer than 50 birds left. At the same time, there was a decline in the breeding success of the remaining birds in Illinois: less egg fertility and hatching success. This decline was correlated with a reduction in genetic variation when this population was

Patterns of Area Sensitivity in Grassland‐Nesting Birds

Abstract: Between 1995 and 1997, we studied breeding birds in fragments of native tallgrass prairie in southwestern Missouri to determine the effect of habitat fragmentation on grassland bird populations. Data on density and nesting success collected in 13 prairie fragments of various sizes revealed three levels of area sensitivity. The most area‐sensitive species, Greater Prairie‐Chicken ( Tympanuchus cupido), was absent from small prairie fragments. An intermediate form of area sensitivity was apparent in only one species, Henslow's Sparrow (Ammodramus henslowii), which occurred in lower densities in small than in large prairie fragments. Based on census (i.e., distributional) data, only those two species were area‐sensitive (i.e., negatively affected by habitat fragmentation) in southwestern Missouri. A species can be sensitive not only on a distributional level, however, but also by having lower nesting success in small than in large prairie fragments. The Dickcissel ( Spiza americana) was the only species that was area‐sensitive on such a demographic level. These data indicate that we cannot rely solely on census data to describe the sensitivity of grassland‐nesting species to habitat fragmentation, but that we also need to investigate demographic data (e.g., nesting success). Whereas it has previously been shown that density measures of forest‐nesting birds do not reliably reflect nesting success in habitat fragments of various sizes, ours is the first study that describes this pattern for grassland‐nesting species.

Reliability of Conservation Actions Based on Elasticity Analysis of Matrix Models

Abstract: Matrix population models have entered the mainstream of conservation biology, with analysis of proportional sensitivities (elasticity analysis) of demographic rates becoming important components of conservation decision making. We identify areas where management applications using elasticity analysis potentially conflict with the mathematical basis of the technique, and we use a hypothetical example and three real data sets (Prairie Chicken [ Tympanuchus cupido], desert tortoise [Gopherus agassizii], and killer whale [Orcinus orca]) to evaluate the extent to which conservation recommendations based on elasticities might be misleading. First, changes in one demographic rate can change the qualitative ranking of the elasticity values calculated from a population matrix, a result that dampens enthusiasm for ranking conservation actions based solely on which rates have the highest elasticity values. Second, although elasticities often provide accurate predictions of future changes in population growth rate under management perturbations that are large or that affect more than one rate concurrently, concordance frequently fails when different rates vary by different amounts. In particular, when vital rates change to their high or low values observed in nature, predictions of future growth rate based on elasticities of a mean matrix can be misleading, even predicting population increase when the population growth rate actually declines following a perturbation. Elasticity measures will continue to be useful tools for applied ecologists, but they should be interpreted with considerable care. We suggest that studies using analytical elasticity analysis explicitly consider the range of variation possible for different rates and that simulation methods are a useful tool to this end.

Effects of Habitat Area on the Occurrence of Grassland Birds in Illinois

Abstract We documented the occurrence of 12 bird species within Prairie Ridge State Natural Area, Jasper County, Illinois, a matrix of nine grassland tracts (range 7–120 ha, totaling 489 ha), from 1994 to 1997 and analyzed the presence of these species relative to the area of the nine grassland tracts. Grassland tract area was correlated with the occurrence of greater prairie-chickens (Tympanuchus cupido) (P = 0.016), upland sandpipers (Bartramia longicauda) (P = 0.012), savannah sparrows (Passerculus sandwichensis) (P = 0.009) and Henslow's sparrows (Ammodramus henslowii) (P = 0.005). Minimum area requirements varied from 12 ha for grasshopper sparrows (Ammodramus savannarum), 55 ha for northern harriers (Circus cyaneus), 65 ha for greater prairie-chickens and upland sandpipers, to 75 ha for Henlsow's and savannah sparrows. Therefore, grasslands larger than 60 ha may be required to attract nine breeding grassland bird species. Each grassland tract was divided into 2- to 6-ha management units (mode = 2.8 ...

Land-Use Patterns Surrounding Greater Prairie-Chicken Leks in Northwestern Minnesota

To better manage wildlife populations, managers must know which combination of land uses creates optimal habitat. We used spatial analysis at a landscape scale to describe land-use patterns and patch characteristics surrounding Irks of greater prairie-chicken (Tympanuchus cupido pinnatus L.) in the Agassiz Beach Ridges (ABR) landscape (2,467 km 2 ) in northwest Minnesota. We hypothesized that types and patterns of land use favorable to greater prairic-chickens would be associated positively with lek versus non-lek points, and particularly more stable (traditional) leks. Using a Geographic Information System (GIS), we analyzed land-use proportions and patch characteristics within an 810-ha area (1.6-km radius) surrounding traditional leks, temporary leks, and randomly located non-lek points. We found locations of greater prairie-chicken leks were strongly dependent on land usc as revealed by a multivariate analysis of variance (MANOVA; P < 0.001). A discriminant function analysis and univariate analysis of variance (ANOVA ) showed that several land-use characteristics were associated most strongly with leks: smaller amounts of residential-farinstead, sinaller amounts and smaller patches of forest, and greater amounts of Conservation Reserve Program (CRP) lands. Comparisons between traditional and temporary leks revealed that traditional leks were surrounded by a lesser proportion of forest and cropland than were temporary leks (P < 0.001 ). Univariate ANOVAs showed that traditional leks also were associated with larger patches of grassland (P < 0.001), and grassland (P = 0.016) and forest patches (P = 0.017) having more irregular shapes. Our study suggests efforts to manage and conserve greater prairie-chicken populations in the Tallgrass Prairie Region should focus on landscape-scale land-use patterns in addition to local habitat characteristics. Landscape scale efforts could include enlarging grasslands around traditional leks by completing prairie restorations and CRP plantings, while local-scale strategies should seek to improve the quality of habitat in existing and new grassland areas.

Simulation of reproductive stages limiting productivity of the endangered Attwater's prairie chicken

Particularly where ground-nesting birds are concerned, conservation biologists require simulation models that explicitly represent population parameters affecting the first year of life. For this reason, we developed and evaluated a computerized model that explicitly represents prairie chicken ( Tympanuchus cupido) clutch size, egg hatchability, nesting success, brood survival, survivorship of chicks within successful broods, and juvenile and adult survival. Sensitivity analyses of these variables suggest that the proportion of hens losing their entire brood would have the greatest influence on the number of prairie chickens in the subsequent spring breeding population. We then used the model to compare the relative importance of three reproductive parameters of endangered Attwater’s prairie chicken ( T. c. attwateri) populations that are known to be significantly less productive than those of the greater prairie chicken ( T. c. pinnatus). When long-term nesting success, brood survival, and number of chicks per brood prior to brood breakup were individually increased, values for each parameter had to be substantially greater than typically seen in greater prairie chicken populations before the decline in Attwater’s prairie chicken numbers was reversed. When these three variables were increased simultaneously, ≈90% of the difference between Attwater’s and greater prairie chicken values had to be closed before the decline in number was reversed.

Genetic Evaluation of a Demographic Bottleneck in the Greater Prairie Chicken

Although the theoretical relationship between population size, fitness, and genetic variation is well established, only a few studies have provided direct evidence that ties a decline in both genetic variation and fitness to a demographic bottleneck for a natural system. We report on a genetic comparison of four populations of the Greater Prairie Chicken ( Tympanuchus cupido) with different demographic histories. Specifically, we compared a population from Illinois that has suffered an extreme demographic contraction and an associated decline in population fitness (measured in terms of hatchability rates) with populations from Kansas, Nebraska, and Minnesota with no known history of bottlenecks or associated declines in fitness. Using the polymerase chain reaction, we amplified six microsatellite loci from which levels of heterozygosity, allelic diversity, and geographic differentiation (FST and RST ) of the studied populations were estimated. Results of this analysis showed that the Illinois Prairie Chicken had the lowest estimate of mean heterozygosity per locus and approximately two‐thirds the allelic diversity, sharing 95–100% of all their alleles with each of the other populations. This finding suggests that the Illinois Prairie Chicken originally had higher levels of genetic diversity that were subsequently lost through an extreme demographic contraction. To our knowledge this is the first example of loss of genetic diversity being associated with a decrease in population fitness as a result of a known demographic bottleneck in a wild bird species. Evaluación Genética de un Cuello de Botella Demográfico en la Gran Gallineta de la Pradera Aunque la relación teórica entre el tamaño poblacional, la aptitud biológica y la variabilidad genética ha sido bien establecida, son pocos lo astudios que han proporcionado evidencia directa que asocie una disminución de la variación genética y de la aptitud biológica con un cuello de botella demografico en sistemas naturales. Reportamos una comparación genética de cuatro poblaciones de la gran gallineta de la pradera (Tympanucus cupido) que tuvieron historias demográficas diferentes. Específicamente comparamos una población de Illinois, la cual ha sufrido una contracción demográfica extrema asociada con decrementos en la aptitud biológica poblacional (medida en términos de tasas de eclosión), con poblaciones de Kansas, Nebraska y Minnesota, las cuales no presentan una historia de cuello de botella poblacional ni decrementos en la aptitud bioloógica. Mediante el uso de la reacción en cadena de la polimerasa (PCR) amplificamos seis marcadores de microsatélites con los cuales estimamos niveles de heterocigósis, diversidad alélica y diferenciación geográfica (FST y RST ) en las poblaciones estudiadas. La gran gallineta de la pradera en Illinois presenta el menor valor de heterocigosidad promedio por locus y aproximademente 2/3 de la diversidad alélica, compartiendo 95–100% de sus alelos con cada una de las otras poblaciones. Estos resultados sugieren que la población de Illinois presentaba originalmente niveles mayores de variabilidad genética, los cuales fueron perdidos consecuentemente a través de un contracción demográfica extrema. A nuestro entender, este estudio representa el primer ejemplo en el que se asocia la pérdida de la diversidad genética en una especie de ave silvestre con la disminución en la aptitud poblacional y como resultado de un cuello de botella demográfico conocido.

Genetic Evaluation of a Demographic Bottleneck in the Greater Prairie Chicken

Genetic Evaluation of a Demographic Bottleneck in the Greater Prairie Chicken

Breeding Ecology of Greater Prairie-chickens (Tympanuchus cupido) in Relation to Prairie Landscape Configuration

Abstract To better understand the role of prairie landscape configuration on the population dynamics and conservation of greater prairie-chickens, we compared population trends and breeding ecology of prairie-chickens in prairie mosaic and contiguous prairie landscapes in southwestern Missouri. Over 27 yr, the contiguous prairie landscape supported a stable population, whereas the prairie-chicken population in the prairie mosaic landscape declined. In 1986 and 1987, less than one-third of greater prairie-chicken nests occurred in native prairie habitats in the prairie mosaic landscape, but 90% of nests in the contiguous prairie area were in native prairie. Greater prairie-chicken nests established in agricultural habitats had substantially lower nest success than nests in native prairie or mixed native-exotic grass pastures. Nest success was higher in the contiguous prairie landscape than in the prairie mosaic area in 1 of 2 yr. Habitat use by broods differed between the areas: in the contiguous prairie l...

The Ghost of Genetic Diversity Past: Historical DNA Analysis of the Greater Prairie Chicken

Most, if not all, of the "classic," often-cited examples illustrating the genetic effects of a population bottleneck are open to alternative explanations due to the lack of adequate control populations, that is, low levels of genetic variability are often assumed to be the result of a past population bottleneck without having any prebottleneck measures. Here we provide the first clear case history where both prebottleneck and postbottleneck measures of genetic variability have been collected from a natural system. Analysis of DNA from museum specimens of the greater prairie chicken Tympanuchus cupido from central Illinois revealed the loss of specific alleles (known to have been present earlier in this century) following a demographic contraction. Lost alleles included common ones present in all other populations sampled and others unique to the Illinois population.

Predicting Greater Prairie-Chicken Nest Success from Vegetation and Landscape Characteristics

To aid management of prairie habitat for nesting greater-prairie chickens (Tympanuchus cupido pinnatus), we tested whether vegetation and landscape variables could be used to predict prairie-chicken nest success. We monitored 60 nests during the 1990-92 breeding seasons in southwestern Missouri. Nest success ranged from 28 to 40% over 3 years (x = 35%). We identified 22-variable models (logistic regression) incorporating litter (horizontal, residual) and woody cover (P 0.5). Nest sites with litter cover >25% had a failure rate twice that of nests with 5% was present at nests (P = 0.01), when forb cover was ≤5% (P = 0.009), or when grass cover was ≤25% (P = 0.02). We suggest that managers can use litter accumulation of >25% as a cue to initiate management action such as burning, grazing, or haying.

Fingering a Genetic Bottleneck

ECOLOGYALBUQUERQUE, NEW MEXICO-- Biologists can't always agree when an endangered species has lost genetic richness as its population declined. But a group of researchers directly documented loss of genetic diversity in an imperiled species--greater prairie chickens in Illinois--by comparing DNA from decades-old museum specimens with that of prairie chickens today.

Measuring the Mating Skew

Charles Darwin (1871) defined sexual selection as a difference inreproductive success due to competition over mates, a definition that is still valid today. Being able to quantify such differences is thus essential for explaining the consequences of sexual selection, say, the ornamentation rdisplay behavior of males. In the specific ase of lekking (aggregated, non-resource-based display of males), attempts to do so have proven difficult. Any measure that does not take into account the possibility of random mating to produce the observed pattern of mating success is unsatisfactory as a measure of the intensity of sexual selection (Sutherland 1987; Mackenzie et al. 1995b). That variation in male mating success on leks is systematically higher than expected from pure random mating has been verified by Bradbury et al. (1985) and Mackenzie et al. (1995a). However, these studies do not yet provide means to estimate the expected mating success of individuals displaying together. Since a lek is not itself a trait but an assemblage of several males, each trying to optimize their own fitness (Hoglund and Alatalo 1995), fitness considerations of single individuals are required in explaining the evolution of lekking. The skew index, defined as the ratio of observed to maximum skew (Keller and Vargo 1993; Reeve and Ratnieks 1993), has been gaining popularity as a measure of skewed reproductive success (e.g., Bourke and Heinze 1994; Keller and Reeve 1994; Reeve and Keller 1995), and it has also been used to estimate the expected fitness of lekking individuals (Widemo and Owens 1995). However, this measure has been shown to have undesirable discontinuities (Pamilo and Crozier 1996). Moreover, it interprets random variation as real differences in mating success. This is most clearly seen in models of pure random mating, which nevertheless lead to positive values of the skew measure (Mackenzie et al. 1995b). Recently, Keller and Krieger (1996) proposed a method for correcting the skew index for random variation. We shall show, however, that the corrected measure still is not satisfactory, and we suggest a novel, statistically rigorous method. We give two criteria for a proper measure of skewed mating success. First, it should allow determining the most probable underlying distribution of mating

Introductions of Sharp-Tailed Grouse into Maine

Introductions of sharp-tailed grouse (Tympanuchus phasianellus) into Maine were approved by the Maine Department of Inland Fisheries and Game in 1954. Habitat inventories in 1955 suggested >1800 km2 were available for sharptails in Washington County. Seventy sharp-tailed grouse from North Dakota and Ne? braska were hard released near feeders in Washington County from 1957 to 1961. In the mid-1950's there was an interest in finding a game bird suitable for open land habitats in Maine. Prior to the 20th century, the heath hen {Tympanuchus cupido cupido) may have been present in southern Maine and introductions of greater prairie-chickens (T. c. pinnatus) had failed (Applegate 1993). Introductions of ring-necked pheasant {Phasianus colchicus) and gray partridge (Perdix perdix) had not been successful, probably because of lack of suitable habitat and adverse climate (Dorr 1952). Because most open land habitats in Maine in the 1950's were either dairy farms, open peat bog, or commercial blueberry {Vaccinium spp.) barrens, the Maine Department of Inland Fisheries and Game decided to investigate introductions of sharp-tailed grouse {Tympanuchus phasianellus, Fig.l). A brief survey was conducted by Dr. G. A. Figure 1. Male sharp-tailed grouse dancing on lek. Photo by Randy D. Rogers * Wildlife Division, Maine Department of Inland Fisheries and Wildlife, 650 State Street, Bangor, ME 04401-5654. Present address: Research and Survey Section, Kansas Department of Wildlife and Parks, PO Box 1525, Emporia, KS 66801-1525. This content downloaded from 157.55.39.136 on Tue, 05 Jul 2016 05:15:56 UTC All use subject to http://about.jstor.org/terms 106 Northeastern Naturalist Vol. 4, No. 2 Ammann of the Michigan Department of Conservation (now Michigan Department of Natural Resources) in 1954. Ammann (unpub. Rep., Maine Dep. Inland Fisheries and Game) suggested that the focus on sharptail introductions should be in the blueberry barrens, particularly those in Washington County in eastern Maine. Based on Ammann's report, the Maine Department of Inland Fisheries and Game, now Maine Department of Inland Fisheries and Wildlife (MDIFW), pursued intro? ductions of sharp-tailed grouse. Introductions of sharp-tailed grouse into Maine were not reported in the professional literature. Many of the original documents relating to this work have been or are in danger of being lost. This paper was prepared to document the historic introduction of sharp-tailed grouse into Maine and identify probable causes of failure as suggested by Toepferetal. (1990).

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-