Species: Falcipennis canadensis

Spruce Grouse

Species

Birds

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Terrestrial vertebrates: birds

Encyclopedia of Puget Sound

Classification

Kingdom

Animalia

Phylum

Craniata

Class

Aves

Order

Galliformes

Family

Phasianidae

Genus

Falcipennis

NatureServe

Source:
ELEMENT_GLOBAL.2.104936

Classification

Other Global Common Names

tétras du Canada

Informal Taxonomy

Animals, Vertebrates - Birds - Other Birds

Formal Taxonomy

Animalia - Craniata - Aves - Galliformes - Phasianidae - Falcipennis - (capercaillie, a European grouse).

Ecology and Life History

Short General Description

A North American grouse of the northern spruce and pine forests.

Migration

true - true - false - Schroeder (1985) reported on behavioral differences between individuals migrating shorter or longer distances in Alberta. He described short-distance migration as less than 2 km, while long- distance migrants moved as much as 11 km. Keppie (pers. comm.) reported migration distances of 25 km in central Ontario and 18 km in New Brunswick (unpublished data).

Non-migrant

true

Locally Migrant

true

Food Comments

In summer, spruce grouse feed on berries, insects and ground vegetation. Juveniles eat a greater diversity of foods than do adults, and a higher proportion of their diet is insects (Pendergast and Boag 1970). Blueberries are often noted as a favored food in summer. These grouse subsist exclusively on conifer needles during the winter. The species of tree favored depends on the location, but all have short needles. In the southern portions of the range, pine needles (lodgepole in the west, jack pine in the east) are a common winter food, but white and black spruce are also consumed (e.g., Naylor and Bendell 1989). In Alaska and Maine spruce needles are reported to dominate the winter diet. Larch needles are eaten in Maine in the fall (Allan 1985). Balsam fir and red spruce have also been reported as foods (Keppie, pers. comm.). In New York, balsam fir is the predominant winter food, and tamarack the major late summer-fall food (Chambers, pers. comm.). In one food selection experiment using captive birds in Washington state, it was found that spruce grouse preferred lodgepole pine needles over Engelmann spruce needles, and in fact could not survive over winter on a diet of the spruce alone. The birds in this study could usually distinguish between branches from "activity" trees (roosting/feeding trees) and randomly selected trees (Hohf et al. 1987). Another study in Michigan found that the grouse selected certain trees for winter feeding, and that the individual jack pine trees browsed by spruce grouse had higher crude protein, lower crude fat, and higher ash content that unbrowsed trees. The browsed trees were also older than trees not selected (average of 36.3 years vs. 33.5 years, respectively) (Gurchinoff and Robinson 1972). The reason for selection of older trees is not clear, and this selectivity is curious in light of the fact that the highest recorded densities of spruce grouse occur in jack pine stands only 10 to 20 years old (Keppie, pers. comm.). During incubation, several studies have found that female spruce grouse feed selectively on new leaders of spruce, apparently for the high calcium content (Pendergast and Boag 1970). A study in Ontario showed that females preferred arbutus flowers and spore capsules of POLYTRICHUM mosses in the spring, and that females which produced larger clutches ate proportionately more of these two foods than females producing smaller clutches. Compared with the winter diet, spring breeding- season foods were higher in protein and phosphorous (Naylor and Bendell 1989).

Reproduction Comments

Mating occurs in spring. The males' display includes puffing up the body feathers, strutting and tail spreading, a "squeak call," short flights ("flutter flights") between tree and ground with rapid wing beats either during the ascent or descent, and occasionally, a very brief standing display of 1 to 3 rapid wing beats which produces a quiet but audible thump (Robinson 1980). The latter, as well as the flutter flight has sometimes been called "drumming", but this is misleading (Keppie, pers. comm.; Robinson, pers. comm.). The noise from the display is audible for less than 100 m even under good conditions, and thus bears little resemblance to the loud drumming of ruffed grouse. Franklin's race gives a loud double clap, like hands clapping, as it alights in its flutter flight. The flutter flight displays have several variations that are briefly described by Robinson (1980). Males and females are apparently both promiscuous and do not form pair bonds (Ellison 1973). Copulatory behavior was described by Harju (1971). Median date of commencement of egg laying was 15 May in Ontario (range 8-21 May, 5 yr of data), 18 May in New Brunswick (range 14-21 May, 7 yr data), and 29 May in Alberta (range 28 May - 1 June, 4 yr data) (Keppie and Towers, unpublished data). In Michigan laying occurred in late May to early June (Robinson 1980). Commencement of egg-laying may be influenced by plant development, as year to year variation in median dates has been shown to be correlated with first flowers of blueberry and trailing arbutus, and the dates for 50% snow cover (Keppie and Towers 1990). Male displays cease soon (within nine days) after the median date of commencement of egg laying (Keppie 1991). Females lay eggs over a period of several days and commence incubating only after the clutch is completed. Robinson (1980) estimated that hens lay an egg about every 2 days, so that it would take 10 to 12 days to complete clutch of 5 or 6 eggs. Keppie (1982) used the figure of 1.5 days per egg. Clutch size varies across range. Keppie (1982) compared production of juveniles in populations from New Brunswick (race CANACE) and Alberta (race FRANKLINII). Clutch size was significantly larger in New Brunswick than in Alberta (5.6 eggs vs. 4.8 eggs, respectively), but average brood size did not differ between the two populations (about 3.3 chicks per brood). Among New Brunswick females, yearlings produced fewer eggs per clutch than did older females ("adults"). There was no difference among Alberta females of different ages. Clutches in a Michigan study averaged 5.7 eggs (Robinson 1980). In Ontario, large clutch size was associated with high intake of trailing arbutus flowers and moss spore capsules; grouse relied on spring diet and stored reserves for nutrients required for clutch formation (Naylor and Bendell 1989). Keppie (1975) reported on previous compilations of clutch sizes. Over the entire distribution of spruce grouse, clutch size averages 5.8 eggs. Alaskan grouse (race OSGOODI) had the largest average clutch size, 7.5 eggs. This is consistent with a general trend of increased reproductive potential with increasing latitude. Incubation lasts 21-23 days (Robinson 1980, Keppie 1982), but also has been reported as 23-24 days. During incubation the female spends over 90 percent of her time on the nest (McCourt et al. 1973). It takes about 30 days from the commencement of laying to hatching. Median date of hatching was 15 June in Ontario, 16 June in New Brunswick, and 29 June in Alberta (Keppie and Towers, unpubl. data). Young are tended by the female. The precocial young can fly short distances by 6 days of age and can feed themselves immediately. Reports of very large broods are likely due to mixing of chicks between broods. This is known to occur in chicks that are more than 10 days old (Keppie 1975). Robinson (1980) documented several instances of chicks switching broods, and recorded combined broods as large as 14 chicks. Individual females produce one clutch per season. A few birds attempt renesting when a first clutch is destroyed. Keppie (1991) estimated the frequency of renesting at 7.6%. Dispersal of young occurs in late summer-early fall. Females first breed as yearlings, but yearling males generally do not breed. Keppie (1982) compared breeding rates of females of different ages and different races. He estimated that at least 94% of New Brunswick females did nest. Between 84 and 100% of the females had broods in the New Brunswick population, and yearlings did not differ from adults (at least 2 years old) in frequency with broods. In the Alberta population (subspecies FRANKLINII), only 40% to 62% of females had broods, and yearlings less often had broods than did older adults. Data on percentage that nested was not obtained for this population, but no evidence was encountered to suggest that some females did not nest. In Michigan, 67% to 88% of females had broods each year from 1965 to 1969 (Robinson 1980). Szuba and Bendell (1988) found that 44% of males did not obtain territories (and presumably, therefore did not breed) until they were adults (their 3rd spring). Some were nonterritorial for 3 or more years. Only 10% of adult males were nonterritorial, and presumably nonbreeding. Most birds breed in not more than two seasons. Keppie (1982) found a much higher nest success rate (proportion of nests in which at least one egg hatched) in a New Brunswick population than in an Alberta population (81% vs. 29% success, respectively) due to much greater nest predation rates in Alberta than New Brunswick. These differences were apparently related to poorer nest concealment in Alberta, where the forest had much less ground cover and shrubs (Redmond et al. 1982). Keppie and Herzog (1978) found that within an Alberta population, nest success was highest among well concealed nests compared to poorly concealed nests. Coastal Alaskan grouse had slightly lower nest success rates than New Brunswick grouse (Keppie 1982); overall production in the New Brunswick population was nearly double that of the Alberta population (2.0 end of season juveniles per female versus 1.1, respectively). Poor productivity in Alberta was associated with years with cold, wet weather during incubation (Smyth and Boag 1984). Spruce grouse have the nickname "fool hen" because they are notoriously unwary of humans. They have been noted to be very wary of predators, however (Robinson, pers. comm.). They do not flush readily and are easy to catch with a noose on a pole. A female incubating a nest of eggs usually will not flush unless she is touched by the intruder (Robinson 1980).

Ecology Comments

Populations generally occur at low densities, spaced by male and female territoriality during breeding, nesting, and, to a lesser extent, brood rearing (Keppie 1987). Females are territorial during breeding and nesting, and clearly avoid one another during this period (Herzog and Boag 1977, Robinson 1980). Males maintain their own territories during the courtship and nesting period, often using the same territory year-round for life (Robinson 1980). Only one male, in 5 years of study on two populations in Gogama, Ontario, was known to move its territory, and then only about 300 meters (Szuba and Bendell 1988). Female aggressive calls during mating and egg laying apparently resulted in evenly spaced female territories in Herzog and Boag's (1977) study in Alberta. Rarely are "flocks" larger than 2 individuals in spring and summer (except for females with broods), and even in fall and winter, the average flock size calculated from observations of 268 flocks was 3.0 birds per flock (Ellison 1973). Larger autumn flocks (average of 3.8 birds) were partially accounted for by females still with broods. Telemetered birds showed that in late fall and winter flocks were very temporary, with the same birds associating for only a few days, and that birds were probably unrelated (Ellison 1973). The largest flocks recorded were 6 to 15 birds. Adult males apparently remain quite solitary even in winter, but juveniles are less solitary (Ellison 1973). Robinson (1980), in Michigan, found fall flocks of 4 to 12 spruce grouse, composed of mixed sexes, ages and families. The proportion of unbanded birds in these flocks was somewhat higher than that encountered in August, suggesting that birds were moving in from outside the study area, and that these larger flocks were probably composed of dispersing birds. In Alaska, Ellison (1973) found that home range sizes were highly variable among individuals, ranging from 6 to 21 ha for preincubating females, 6 to 155 ha for brood-rearing females, 3 to 20 ha for molting males, 6 to 160 ha for either sex in fall, and 3 to 113 ha in winter. Robinson (1980) also reported highly variable range size for females with broods, but concluded that 12 to 16 ha would be adequate on the Yellow Dog Plains of Upper Michigan. Home range for broods on Mt. Desert Island, Maine, was 13-26 ha (O'Connell et al. 1995). Two populations at Sevogle, New Brunswick, ranged from 9.8 to 21.9 grouse per sq km (adult males and females and yearlings present during period of 1 May to 30 June) over a 4 year period (Keppie 1987). Similar densities were reported for a population in southwestern Alberta, where population density in spring varied between 10.5 and 19.3 birds per sq km over a ten year period (Boag et al. 1979). Further data showed a fluctuation of between 5 and 30 birds per sq km over 21 years; a population decline was attributed to forest maturation (Boag and Schroeder 1987). It is interesting that population densities were so similar in these populations, because habitat characteristics were quite different. Populations in New York occur at estimated densities of 1.0 to 9.6 birds per sq km (composition unspecified, "breeding population;" Bouta and Chambers 1988). A Michigan population in the Yellow Dog Plains of Marquette County had 4.6 to 9.0 birds per sq km (presumably both sexes and yearlings) in spring (Robinson 1980). Grouse from Alaska's Kenai Peninsula occurred at intermediate spring densities of 7 to 11 birds per sq km (presumably both sexes and yearlings) over an area of habitat some 2000 sq km. This population must have numbered over 10,000 birds in the 1960s (Ellison 1973). The highest reported densities for this species are from central Ontario, where populations exceed 50 birds per sq km in prime habitat (Szuba and Bendell 1983). Keppie (pers. comm.) also has documented population densities of 50 birds per sq km. At Gogama, Ontario, Szuba and Bendell (1988) found densities of 28.0 to 36.0 males per sq km in May. One study in Alberta suggested that late spring population size was rather stable (Boag et al. 1979). Young tend to disperse in the fall, but more so in some areas than others. Overall emigration rates for both sexes in New Brunswick exceeded emigration in an Alberta population (Keppie 1982). A higher percentage of female juveniles disperse than males (e.g., 95% vs. 77% in New Brunswick). Females were shown to disperse farther than males (an average of 5 km vs. 3.7 km, respectively) in a Michigan population (Robinson 1980). In Alberta, yearling and adult annual survival averaged 68% overall (Boag et al. 1979). Female survival, at 63%, was lower than male survival, at 72%, producing a slight, but significant, male bias in sex ratio among adults (1.12 males: 1 females) (Boag et al. 1979). Annual survival rates for all adults and yearlings in New Brunswwick was 47% (Keppie 1987). Keppie (1979) reported an overwintering survival rate of 88% for all ages and sexes in a population in southwest Alberta. Overwinter survival of adults and yearlings, males and females was similar in this population. In Michigan's Yellow Dog Plains, adult males survived at rate of 50% per year, while females had a slightly lower rate of 45% per year. Robinson (1980) noted that the Michigan population's survival rate was intermediate between the Alberta populations and an Alaskan population described by Ellison, which had 31-38% adult survival. Robinson concluded that survival seems to balance clutch size variation throughout the range: the Alaskan population having the largest clutches, and lowest adult survival, Alberta at the opposite end with smaller clutches and highest survival, and Michigan in the middle on both traits. There is little in the literature about longevity, despite many banding studies. The oldest individuals in Robinson's studies were three males, two that reached 6 years, and one that was at least 7.5 years old. The oldest female lived 5.5 years (Robinson 1980). Although a number of studies of population dynamics have been conducted, it is still not possible to generalize about the main factors influencing population size across the species' range. Results in different populations and in different years within the same population have been contradictory. Rates of emigration and juvenile recruitment, especially survival through the first winter, clearly have a strong impact on population size, but these factors are not clearly related to density, or predictable from simple physical variables such as habitat characteristics or weather (Boag et al. 1979, Robinson 1980, Keppie 1982). Female and male territoriality may also affect some aspects of population density and production (Ellison 1973, Herzog and Boag 1977, Szuba and Bendell 1988).

Length

Weight

492

Conservation Status

NatureServe Global Status Rank

Global Status Last Reviewed

1996-11-25

Global Status Last Changed

1996-11-25

Other Status

LC - Least concern

Distribution

Conservation Status Map

Global Range

H - >2,500,000 square km (greater than 1,000,000 square miles) - H - RESIDENT: Canada and the northern United States, from central Alaska, Yukon, and Mackenzie east to Labrador, and south into the mountains of northeastern Oregon, central Idaho, western Montana, and northwestern Wyoming; farther east, the southern extent is the extreme northern parts of Minnesota, Wisconsin, Michigan's Lower Peninsula, New York, Vermont, and New Hampshire, and eastern Maine (AOU 1983).

Global Range Code

Global Range Description

>2,500,000 square km (greater than 1,000,000 square miles)

ELEMENT_GLOBAL.2.104936