E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Dendragapus fuliginosus (Ridgway)
Sooty Grouse
Family: Phasianidae

Species account author: Jamie Fenneman

© Mike Ashbee  Email the photographer   (Photo ID #8524)


Distribution of Dendragapus fuliginosus in British Columbia.
(Click on the map to view a larger version.)
Source: Distribution map provided by Jamie Fenneman for E-Fauna BC

Introduction


Introduced into the northwestern United States (Idaho, Montana) and subsequently spread into southeast B.C. Two subspecies in BC:

1) Dendragapus fuliginosus sitkensis
2) Dendragapus fuliginosus fuliginosus{i/}.

Species Information

Adult male
Upperparts, including the wings, wholly dark sooty-grey tinged with brown and with fine, faint darker grey vermiculations. The tail is black or dark blackish-grey with sharply defined pale grey tips to the feathers forming a distinct pale terminal band on the tail. The breast and underparts are dark sooty-grey (darkest and often almost blackish on the upper breast), darker than the upperparts and lacking any brown tinge. The feathers on the sides and flanks have white shaft streaks and white tips, and the undertail coverts are blackish with grey mottling and broad whitish tips to the feathers. The underwing coverts are mostly white. The head is dark sooty-grey or almost blackish (darkest on the throat), usually with some fine whitish flecking on the chin and throat. When displaying, the male inflates large chambers on each side of the neck which appear as large areas of yellow, warty, wrinkly bare skin surrounded by a large circular ruff or rosette of dark-tipped white feathers; the male also erects fleshy, orange-yellow (sometimes bright red) “combs” (ridges of bare skin) above the eyes when displaying. The iris is dark, the short bill is blackish, and the legs and feet are dark grey with yellow soles of the feet and a dense covering of grayish-brown feathers over the legs and upper surfaces of the toes.

Adult female
Upperparts, including the wing coverts, intricately mottled with brown, rufous, grey, and black, with narrow white tips and shaft streaks on the scapulars and some wing coverts; the flight feathers are blackish with brown mottling on the outer webs. The tail is mottled and shows the suggestion of alternating grayish, blackish, and rusty-brown bands as well as a distinct pale grey terminal band. The breast is mottled with brown, rufous, grey, and black but is slightly paler and greyer in colouration than the upperparts. The belly, flanks, and undertail coverts are similarly mottled but with large, bold whitish tips to the feathers that give the underparts an extensively white-spotted appearance. The head and neck are sooty grey-brown with brownish mottling on the head and whitish and buffy spotting and mottling on the throat and foreneck (often forming a pale outline around the throat). Bare part colouration (iris, bill, legs, feet) similar to the adult male.

Juvenile
This plumage is held during the summer of the first year. It is overall very similar to the adult female, but many of the body feathers have diagnostic pale shaft streaks. As well, the crown has varying amounts of rusty-brown and the narrow, pointed tail feathers have pale shaft streaks on the outer portions of the feathers.

Measurements
Total Length: 40-50 cm
Mass: 835-1,280 g

Source: Zwickel and Bendell (2005)

Biology

Identification

The identification of Sooty Grouse is generally straightforward within most of its range, where the only other grouse species is the Ruffed Grouse. The Ruffed Grouse is easily distinguished from female Sooty Grouse by its much smaller size, short but pronounced crest, barred underparts, and black subterminal band on the tail (lacking the pale terminal band that is present in Sooty Grouse). In some areas along the crest and eastern slopes of the Coast and Cascade Mountains, the distribution of the Sooty Grouse overlaps with that of the Spruce Grouse. Female Spruce Grouse are similar to female Sooty Grouse but are much smaller, shorter-necked, and shorter-tailed with less heavily-patterned underparts; the tail lacks the pale terminal band that is present in female Sooty Grouse.

The identification of this species along the eastern slopes of the Coast and Cascade Mountains is particularly complex due to the presence of the very similar, very closely related Dusky Grouse. The situation is even more complicated as a result of occasional hybridization between these two species in this area, but the discussion here will be restricted to pure individuals of each species. Both sexes of Sooty Grouse can be distinguished from Dusky Grouse (at least, those subspecies in B.C.) by the presence of a pale grayish terminal band on the tail. Dusky Grouse have no pale terminal band on the tail or, at best, very indistinct and narrow pale tips to the tail feathers. In addition, Sooty Grouse have 18 tail feathers (20 tail feathers in Dusky Grouse) that are more rounded at the tips and graduated, giving the tail a rounder (less squared) appearance when spread. Aside from these differences in tail shape and colour, and slight differences in overall colouration (female Sooty is somewhat darker and browner, female Dusky somewhat paler and greyer) the females of these two species are very similar.

The male Sooty Grouse is noticeably darker (sootier) than the male Dusky Grouse, which is a paler blue-grey colour overall, but the differences between the males of these two species are most evident during courtship displays. When displaying, the cervical apteria (neck pouches) of the male Sooty Grouse are inflated and appear as patches of bare, warty yellow skin on the side of the neck that are surrounded by a ruff of dark-tipped white feathers. In contrast, the displaying male Dusky Grouse inflates purplish-red cervical apteria that have less distinct warty tubercles on the skin and are surrounded by a ruff of more extensively white neck feathers. An additional behavioural difference between these two species is the tendency for male Sooty Grouse to display from an elevated perch (log, stump, low branch) or within the canopy of a coniferous tree, whereas the male Dusky Grouse typical displays from the ground. See ‘Vocalizations’ section for notes on differences in song between these two species.
Vocalizations

The male’s song consists of a series of six far-carrying, very deep hoots that often accelerate in tempo slightly towards the end and can be heard at distances of up to 300-500 m. The song is similar to the song of the male Dusky Grouse but is higher-pitched and much louder (song of Dusky Grouse rarely audible at distances greater than 50 m) and consists of six (rather than five) hoots. The male also sometimes gives a single whoot call during courtship with the female, and produces a low, growling call during antagonistic encounters. The female produces a precopulatory whinny during the breeding season, and often gives chicken-like clucking notes throughout the year.

Source: Zwickel and Bendell (2005)

Breeding Ecology

Courtship
Courtship activities begin in late winter and early spring and continue through April and early May. Males regularly mate with multiple females over the course of the breeding season, but it is unknown whether females mate with more than one male. Males attract females to their territory through singing, which is usually done from an exposed perch such as a log, stump, low branch, or even from within the canopy of a small coniferous tree. Males also perform “flutter flights” along with singing which also serve to attract females to the territory. Once a female enters the male’s territory, he engages in an elaborate display that involves inflating the cervical apteria (chambers on the neck) to expose the bare yellow skin and surrounding rosette of white feathers, raising the yellow-orange combs (ridges of bare skin above the eyes), and raising and fanning the tail. If the female continues to approach the male, he will rush towards her while producing a series of whoot call notes and bobbing the head, often engaging in a brief chase. Once the female decides to mate, she will crouch and often produce a whinnying call in order to solicit copulation.

Nest
Nest construction occurs in April or May (earlier in the lowlands) and is completed entirely by the female. The nest is placed on the ground and consists of a shallow scrape ~17-23 cm across and ~4-5 cm deep that is lined with dead leaves, twigs, conifer needles, grasses, moss, bark, or rotted wood and often contains a few feathers; all materials are gathered from within the immediate vicinity of the nest. Almost all nests have some form of cover such as shrubs, ferns, grasses, forbs, logs, small trees, or a stump (sometimes as little as a single twig) above the nest for concealment.

Eggs
A clutch of (1) 4-8 (12) eggs is generally laid in late April or May (earlier in the lowlands), although some replacement clutches may be laid well into June or even July. Other than replacement clutches, this species is single-brooded The smooth eggs are pale pinkish-buff and are finely speckled and splotched with dark brown (rarely unmarked). Incubation is done solely by the female, and the incubation period is 25-28 days. Eggs are present in B.C. between late April and early August, although few clutches are reported later than June.

Young
The young are fully precocial upon hatching and leave the nest within the first day. They grow rapidly, are able to fly weakly within 6-7 days, and are capable of short, sustained flights at ~16 days of age. Newly-hatched chicks are reddish-brown on the upperparts and yellowish on the underparts and head, with black, blackish-brown, and reddish-brown mottling on the head and upperparts, two irregular and broken black stripes down the back, and two pale whitish bars across the wings; the short bill is pinkish to dark grey. Once they have left the nest, the female continues to travel with the brood until the late summer or fall (late August to late September), after which time the juveniles disperse and become independent. The young are able to feed themselves immediately upon hatching and rely on the female primarily for protection, cover (brooding), and for direction to productive foraging areas. Older chicks and juveniles feed progressively farther and farther from the female, but return to her side when alarmed or threatened. Dates for chicks and dependent juveniles in B.C. range from mid-May to late September.

Source: Campbell et al. (1990b); Madge and McGowan (2002); Zwickel and Bendell (2005)
Foraging Ecology

The diet of the Sooty Grouse is dominated by plant material throughout the year, although small amounts of animal material are consumed during the summer months. Conifer needles (particularly hemlock) form the bulk of the diet from September to May, and form nearly 100% of the diet during the winter months. Other plant materials that are important in the diet include berries (especially during the summer), fruits, seeds, leaves, buds, and flowers of a wide variety of shrubs and forbs. Also consumes tender tips of fern fronds (bracken fern, lady fern). Juveniles and some adults will consume insects (especially ants and grasshoppers) and other invertebrates during the breeding season. Most foraging occurs on the ground or in trees, with arboreal foraging most important during the winter when heavy snowpacks often hinder foraging on the ground. Like other grouse, this species regularly ingests gravel and small stones to aid with digestion, and can often be found along roadsides where it gathers grit.

Source: Baicich and Harrison (1997); Madge and McGowan (2002); Zwickel and Bendell (2005)

Habitat


This species is closely associated with mature or second-growth coniferous forests throughout its range, including low-elevation forests that are dominated by Douglas-fir, Sitka Spruce, Western Hemlock, or Western Redcedar as well as higher-elevation forests that are dominated by Amabilis Fir, Mountain Hemlock, and Yellow-cedar. It commonly occurs in brushy open areas within these forested habitats, such as clearcuts, burns, forest openings, and mountain meadows, and is often more abundant in these habitats than in nearby closed forests. During the summer, it also ranges above treeline into open subalpine parkland and alpine meadows where there is little or no established tree cover.

Source: Campbell et al. (1990b); Zwickel and Bendell (2005)

Distribution

Global Range

Resident along the Pacific coast of western North America, from southeast Alaska south to northern California, as well as along the Sierra Nevada Mountains and associated ranges of eastern California.
BC Distribution

Resident
Fairly common to common in most areas along the entire coast, including both Vancouver Island and the Queen Charlotte Islands, although it is less common and more local at low elevations on southeastern Vancouver Island and the Gulf Islands and rare in the Lower Mainland (where very little suitable habitat remains). Populations on some islands in the Strait of Georgia (Texada, Lasqueti, Moresby) are the result of deliberate introductions and did not historically support populations of Sooty Grouse. On the mainland, this species occurs primarily along the Pacific slopes of the Coast and Cascade Mountains and is rare to uncommon along the eastern slopes (where it is replaced by the closely related Dusky Grouse). Small numbers range along the western slopes and valleys of the Coast Mountains in northwestern B.C. in areas adjacent to the Alaska Panhandle.

This species undertakes pronounced and well-documented altitudinal migrations throughout the year. Beginning in late summer (August), birds breeding in the lowlands as well as those breeding in alpine areas begin to move to middle elevations where they will spend the winter alongside birds that bred at these elevations. This migration continues throughout the fall, and most birds have reached the wintering grounds by November. These individuals remain at these altitudes throughout the early and mid-winter but begin return to the breeding territories in late winter or early spring (February-March); most birds have reached their breeding territories by late March or early April. During these migrations, particularly in the fall, individuals sometimes wander into areas where they are not normally recorded, such as at sea level in the Georgia Depression. Because it winters in areas with heavy snows and relatively little access, and because it is very quiet and secretive at this time of the year, this species is rarely encountered during the winter despite being common in many regions.

Source: Campbell et al. (1990b)

Conservation

Population and Conservation Status

The Sooty Grouse is generally common throughout its range, although declines have occurred on southeastern Vancouver Island and (especially) in the Lower Mainland where habitat has been lost to urbanization and agricultural development. In other areas, however, this species often responds well to disturbances such as forest harvesting activities and forest fires which open up the forest and promote an explosion of grasses, forbs, and shrubs that provide this species with food. In such instances, the population of Sooty Grouse inhabiting an area often increases dramatically and remains high until the forest has matured to the point where the canopy begins to close. This dynamic creates pronounced fluctuations in population densities of Sooty Grouse in many areas. Breeding populations of Sooty Grouse are sometimes dependent on closed forests within relatively small winter ranges (such as on some coastal islands), however, and clearing of the forests within these winter ranges has the potential to cause localized declines. Because of these localized declines, the species is currently placed on the provincial 'blue list' by the B.C. Conservation Data Centre (CDC) as a species of special concern

Source: Campbell et al. (1990b); Madge and McGowan (2002)

Taxonomy


This species was formerly considered conspecific with the Dusky Grouse (Dendragapus obscurus) under the name “Blue Grouse”, but these two forms were resurrected to species status in 2006 based on differences in adult plumage, the appearance of the downy young, vocalizations, and courtship behaviour as well as significant differences in mitochondrial DNA. Sooty Grouse now encompasses the coastal subspecies of the formerly-recognized “Blue Grouse”, while Dusky Grouse encompasses the interior and Rocky Mountain subspecies. These two species are reported to hybridize in a narrow band along the Coast and Cascade Mountains in British Columbia and Washington. Although the genus Dendragapus formerly included the Spruce Grouse (Falcipennis canadensis), it is now known that Sooty and Dusky Grouse are much more closely related to the sage-grouse (Centrocercus) and Sharp-tailed Grouse and prairie-chickens (Tympanuchus) than to the Spruce Grouse. As a result, the Spruce Grouse is now placed in a separate genus from Dusky and Sooty Grouse.

Four subspecies of Sooty Grouse are recognized, with two occurring in British Columbia. The two additional subspecies are found only in the Sierra Nevada Mountains and associated ranges of eastern California, as well as farther north along the eastern slopes of the Cascade Range, but do not range farther north than Washington.

The two subspecies that occur in B.C. are as follows:

Dendragapus fuliginosus fuliginosus
This subspecies is found throughout the mainland coast of B.C. south of Alaska, as well as on Vancouver Island and all associated islands. It also ranges south along the coast of the United States to northwestern California. Males of this subspecies are more or less indistinguishable from males of the following subspecies (sitkensis), but females are distinguishable by their lack of rufous tones on the upperparts (the upperparts of female sitkensis are distinctly washed with rufous).

Dendragapus fuliginosus sitkensis Swarth
This subspecies is found primarily on the Queen Charlotte Islands and throughout the Alaska Panhandle, and also occurs in small numbers along the Pacific slope of the Coast Mountains in northwestern B.C. Males are essentially indistinguishable from male fuliginosus, but females are distinguishable from female fuliginosus by the rufous tones throughout the upperparts.

Source: Zwickel and Bendell (2005)

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
COSEWIC
UnlistedUnlistedUnlistedUnlisted
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Additional Range and Status Information Links

Additional Photo Sources

General References


Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2019. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 13/10/2019 4:12:51 PM]
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