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blue grouse

Dendragapus obscurus

What do they look like?

Dusky grouse are the second largest grouse species in North America, the only species that is larger are sage grouse. Dusky grouse are 38 to 61 centimeters (12 to 15 inches) long, and males are usually larger than females. Males and females can be hard to tell apart, but males have a slate grey coloration mixed with white, while females have a greyish-brown coloration mixed with white. Both males and females have fan-shaped tails with a grey band along the tip of the tail feathers. This band can be most easily seen on males when they fan their tail out during the spring mating season. Dusky grouse have an eye comb that is especially noticeable in the spring. Male eye combs are yellowish-orange and cover the upper half of their eye. Female eye combs are dull yellow and only cover the upper inner top corner of the eye. Likewise, only males have cervical sacks, which are found at the base of their neck and covered in white feathers. ("Colorado Parks and Wildlife", 2011)

  • Sexual Dimorphism
  • male larger
  • sexes colored or patterned differently
  • Range mass
    0.91 to 1.36 kg
    2.00 to 3.00 lb
  • Range length
    30 to 38 cm
    11.81 to 14.96 in
  • Range wingspan
    61 to 71 cm
    24.02 to 27.95 in
  • Average basal metabolic rate
    4.9570 W cm3.O2/g/hr

Where do they live?

Dusky grouse (Dendragapus obscurus) have a very large range, from the Northwest Territories in northern Canada to northern New Mexico in the United States. They cover the western half of North America, living in the Rocky Mountains and all other nearby mountainous areas such as the Black Hills in South Dakota, Wyoming, and Nebraska. This covers an area of about 2,100,000 square kilometers, with many different elevations. ("Colorado Parks and Wildlife", 2011; Barrowclough, et al., 2004; Bird and Symes, 2008)

What kind of habitat do they need?

Dusky grouse can be found in many habitats including aspen forests near sea level to dense areas of Douglas fir, lodgepole pine, and spruce at the tree line. At different times of the year they can be found in different areas, and they migrate between them. During the summer months, these birds are mostly found feeding in sub-alpine meadows or low lying areas with aspen, chokecherry, service berry, and oak brush. Along with grasshoppers, these plants are their main food source at this time of year. During the winter, while most other animals leave the mountainous areas, dusky grouse stay near the tree line at high elevations. They spend most of the winter roosting in Douglas fir and lodgepole pines feeding on their cones and needles. In the winter, these high elevation areas not only provide plenty of food, but tend to have fewer predators, as most predators follow the larger animals to lower elevations. ("Colorado Parks and Wildlife", 2011; Bird and Symes, 2008; Fowle, 1960)

  • These animals are found in the following types of habitat
  • temperate
  • Range elevation
    0 to 3600 m
    0.00 to 11811.02 ft

How do they reproduce?

Dusky grouse mate from spring to mid-summer. Their mating behavior begins when males start making hooting noises from late March until mid-July. Males find and defend a mating territory by fanning out their tail feathers, hoping, and clapping their wings. Dusky grouse are both lekking and non-lekking birds. This means the males either gather in an area to challenge each other for females (lekking) or the males go out by themselves to search for females. The males continue to hoot into the mid-summer to attract females that have lost their clutch and are willing to mate again. ("Colorado Parks and Wildlife", 2011; Barrowclough, et al., 2004; Fowle, 1960; Martinka, 1970)

After they breed, females find an area to build their nest where it will be protected such as downed trees or thick brush and build the nest using grass and small twigs. They usually lay 7 to 9 eggs during the month of March, although it may vary based on the weather. Generally, the eggs must be incubated for 18 to 21 days after being laid and the chicks begin hatching in late May to early June. If a mother loses her clutch early in the summer, she will often mate again with a willing male. ("Colorado Parks and Wildlife", 2011; Barrowclough, et al., 2004; Fowle, 1960; Martinka, 1970)

  • How often does reproduction occur?
    Dusky grouse breed 1 to 4 times yearly.
  • Breeding season
    Dusky grouse breed from early March to mid-July
  • Range eggs per season
    5 to 24
  • Range time to hatching
    12 to 14 days
  • Range fledging age
    12 to 24 hours
  • Range time to independence
    2 to 3 months
  • Average age at sexual or reproductive maturity (female)
    365 days
  • Average age at sexual or reproductive maturity (male)
    365 days

After the eggs have hatched, the chicks are protected from predators and intruders by their mother who will hiss and flap her wings to scare the intruder. Male dusky grouse take no part in parental care. After the chicks have reached 10 to 28 days of age, the mother and her chicks begin to separate while feeding, but the mother can often be found perched over her chicks, keeping a watchful eye for intruders. By early autumn, the young stop following the mother and become independent, after which they begin grouping with other adults. ("Colorado Parks and Wildlife", 2011; Bird and Symes, 2008; Fowle, 1960)

  • Parental Investment
  • altricial
  • female parental care
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female
  • post-independence association with parents
  • inherits maternal/paternal territory

How long do they live?

Dusky grouse usually have a short lifespan. About 50 percent of these birds die during their first year. The birds that live past their first year have an average lifespan of about three years. In areas with plenty of food and few predators they have been known to live up to 14 years. (Redfield, 1975)

  • Range lifespan
    Status: wild
    1 to 14 years
  • Average lifespan
    Status: wild
    3 years
  • Typical lifespan
    Status: wild
    4 to 12 months

How do they behave?

Dusky grouse stay in smaller groups during the warmer months and form larger flocks during the winter, when they spend most of their time in the tree tops eating needles and cones. In the summer months, the largest flocks usually just include a female and her chicks, about 6 or 7 birds. During the winter, they may be found in flocks of 15 to 20 birds. This difference is due to the amount of food and shelter available at different times of the year. When not as much food is available, many dusky grouse join larger groups. During the summer, they spread out to areas with blueberry, chokecherry, or gooseberry bushes. ("Colorado Parks and Wildlife", 2011; Fowle, 1960; King and Bendell, 1982; Redfield, 1975; Schroeder, 2004)

Home Range

Dusky grouse move between alpine habitats at the tree line where they spend their winters and lower lying areas with plenty of food in the summers. They tend to use the same areas year after year. Young birds follow their mother and continue to migrate between these areas as they get older. These birds usually travel short distances, but in some instances dusky grouse travel up to 30 miles between their summer and winter ranges. ("Colorado Parks and Wildlife", 2011; Fowle, 1960)

How do they communicate with each other?

Dusky grouse communicate socially through a series of chirps and peeps throughout the year. These sounds are very subtle to the human ear and are hard to tell apart from other forest birds. They are used to alert each other to predators, and are especially common between a mother and her young. If the mother and young get separated, the mother will call her young with a series of deep clucks that sound similar to the hoot males give during the breeding season. During the mating season, a male will use hooting to communicate with females. Males also clap their wings together to make a loud series of thumps. This call is used to defend their territory and to call females. ("Colorado Parks and Wildlife", 2011; Bird and Symes, 2008; Fowle, 1960)

What do they eat?

Dusky grouse spend their winters in spruce, Douglas fir, and other pine trees and eat the needles and cones these trees produce. A favorite this time of year is the seed found in whitebark pine cones. It is high in protein and fats, which help them survive the cold months. During the summer, dusky grouse eat a variety of berries from blueberry, chokecherry, gooseberry, and huckleberry bushes. They also eat a variety of insects, especially grasshoppers. These birds need a small piece of gravel inside their craw (a muscular organ found at the base of their neck) to grind up large foods. When the foods are ground enough, they pass into the stomach and intestines where the nutrients are absorbed. (King and Bendell, 1982; Stewart, 1944)

  • Animal Foods
  • insects
  • Plant Foods
  • leaves
  • seeds, grains, and nuts
  • fruit

What eats them and how do they avoid being eaten?

Dusky grouse are eaten by many predators in their habitat. Coyotes, red foxes, Canada lynx, bobcats, mountain lions, grizzly bears, and black bears will eat dusky grouse if they see an opportunity. Other predators include American badgers, ermines, pine martens, hawks, and both golden and bald eagles. Their best defense is their camouflage coloring and their ability to fly. Dusky grouse are not very good fliers and can only fly in short bursts, so they are not able to get away from birds of prey in this way. It is harder for ground predators to catch dusky grouse. Many predators eat the eggs out of their nests, which are found on the ground. This gives them a high death rate at a young age. ("Colorado Parks and Wildlife", 2011; Fowle, 1960; Redfield, 1975)

  • These animal colors help protect them
  • cryptic

What roles do they have in the ecosystem?

These birds are an important food source for many predators. They also help control insect populations, such as grasshoppers, and disperse seeds from berry bushes throughout the ecosystem. In addition, dusky grouse may carry several parasites. ("Colorado Parks and Wildlife", 2011; Bendell, 1955)

  • Ecosystem Impact
  • disperses seeds
Commensal or parasitic species (or larger taxonomic groups) that use this species as a host

Do they cause problems?

Dusky grouse have very few negative impacts on humans. The only possible negative impact might be the spread of parasites from eating their meat. However, this is very uncommon and can be easily avoided through proper food handling and preparation. (King and Bendell, 1982)

How do they interact with us?

Dusky grouse are hunted by humans in their mountainous habitats; this gives hunters the opportunity to enjoy the outdoors and a possible meal for their dinner table. ("Colorado Parks and Wildlife", 2011)

Are they endangered?

Dusky grouse have had a very small population decrease over the last 40 years. There are about 3,000,000 adult birds in the wild, and their decrease is so small that the species is still listed as 'least concern' by the International Union for Conservation and Nature (IUCN). (Bird and Symes, 2008)

Some more information...

Dusky grouse are a newly described species. The species formerly known as blue grouse (Dendragapus obscurus) was divided into dusky grouse (Dendragapus obscurus) and sooty grouse (Dendragapus fuliginosus) in 2006 based on DNA evidence. Sooty grouse live along the Pacific coast, from northern Canada to Southern California in the Sierra Madre Mountains. On the other hand, dusky grouse are found in inland North America, following the Rocky Mountains and other nearby montane areas. (Schroeder, 2004)

Contributors

Steven James (author), University of Wyoming, Hayley Lanier (editor), University of Wyoming - Casper, Leila Siciliano Martina (editor), Animal Diversity Web Staff.

References

2011. "Colorado Parks and Wildlife" (On-line). Accessed November 13, 2013 at http://wildlife.state.co.us/Pages/Home.aspx.

Barrowclough, G., J. Growth, L. Mertz, R. Gutierrez. 2004. Phylogeographic structure, gene flow and species status in blue grouse (Dendragapus obscurus). Molecular Ecology, 13 Issue 7: 1911-1922.

Bendell, J. 1955. Disease as a control of a population of blue grouse. Canadian Journal of Zoology, 33: 195-223.

Bird, J., A. Symes. 2008. "Dusky Grouse (Dendragapus obscurus) Bird life international" (On-line). Birdlife.org. Accessed November 07, 2013 at http://www.birdlife.org/datazone/speciesfactsheet.php?id=32361.

Fowle, D. 1960. A study of blue grouse (Dendragapus obscurus Say) on Vancouver Island, British Columbia. Canadian Journal of Zoology, 38: 701-713.

King, D., J. Bendell. 1982. Foods selected by blue grouse (Dendragapus obscurus fuliginosus). Canadian Journal of Zoology, 60: 3268-3281.

Martinka, R. 1970. Structural characteristics and ecological relationships of male blue grouse (Dendragapus obscurus Say) territories in southwestern Montana. Canadian Journal of Zoology, Volume 38: 701-713.

Redfield, J. 1975. Comparative demography of increasing and stable populations of blue grouse (Dendragapus obscurus). Canadian Journal of Zoology, 53: 1-11.

Schroeder, M. 2004. Blue grouse (Dendragapus obscurus) are now considered to be two. Newsletter of Grouse Specialist Group, 32: 4-6. Accessed November 07, 2013 at http://wdfw.wa.gov/publications/01273/wdfw01273.pdf.

Stewart, R. 1944. Food habits of blue grouse. The Condor, 46: 112-120.

 
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James, S. 2014. "Dendragapus obscurus" (On-line), Animal Diversity Web. Accessed May 20, 2024 at http://localhost:2015/accounts/Dendragapus_obscurus/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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