Friday, November 28, 2014

Turkey Cousins - Grouse, Unfamiliar Denizens of Mountain Interior Forest

Nationwide Wild Turkey (Maleagris gallopava) are doing well; Partners in Flight (PIF) estimate (citation below) a population of 6.9 million in the U.S. NPR had a segment on turkey entering suburbia, which means for Americans there is good chance to see them regularly without trying.

Why can't that be said of the 18 million (PIF population estimate) Ruffed Grouse (Bonasa umbellus) ? Or another gamebird, the Spruce Grouse (Falcipennis canadensis), which has an estimated population of 11 million. The third species of grouse in this part of the country (Montana) should be somewhat unknown; the Dusky Grouse (Dendragapus obscurus) has a population of around 300,000 only.

Several explanations come to mind: a) size b) coloration c) behavior d) habitat structure and e) hunting.

  • Size - Turkeys are huge, 11-24 pounds with a average wingspan 4.5 feet. The largest grouse, Dusky, weighs only 2.6 pounds with a two foot wingspan.  
  • Color - Turkeys (both sexes) are coppery/bronze iridescent from a base of dark brown/blackish feathers. Both sexes of Ruffed Grouse are similar in plumage; have one of two colors, gray and red in a camouflage pattern. Spruce and Dusky are sexually dimorphic, males are mostly all black and females are a splotchy earthy brown.
  • Behavior - Gobbling of the turkey can be heard a mile away.  Sounds attract females wherein males perform display (fanned tail et al); this is a "mobile lek". Ruffed Grouse drum (wings beating) at a display site; female visits and chooses to mate or not. Spruce "hoots" with the assistance of colored air sacs at a solitary site; not lek-like. Dusky also make low-pitched hoots via air sacs using a modified lek scenario; several males congregate somewhat (well-spaced) in forest habitat.
  • Habitat structure - Turkey use forest/forest edge that is somewhat "open". Ruffed prefer deciduous/coniferous interface at lower elevations than the other two grouse. Dusky prefers conifer forest with openings while Spruce likes dense conifer forest.
  • Hunting - Turkeys are the second most popular game animal (deer are number one) for hunters in North America.
Have a look at the photos below to become more familiar with these other gamebirds. Winter is a good time for finding grouse, especially Ruffed in the East...think footprints :-)

References: Partners in Flight Science Committee 2013. Population Estimates Database, version 2013. Available at http://rmbo.org/pifpopestimates. Accessed on 11-28-2014.
The Sibley Guide to Bird Life and Behavior, David Allen Sibley, 2001, Alfred A. Knopf, New York.
Birds of North America, Fred Alsop lll, 2001, DK Publishing, New York.

Ruffed Grouse

Spruce Grouse (female)

Dusky Grouse (female)

Dusky Grouse (male)

Spruce Grouse (hatchling)