Spruce Grouse (Falcipennis canadensis)

Spruce GrouseSpruce Grouse distribution map

Status/Protection

Population Information

Wisconsin DNR is currently conducting a survey of Spruce Grouse across 10 northern counties, which should provide an estimate of population size. There are currently no standardized, range-wide protocols that monitor Spruce Grouse populations.

Life History

Habitat Selection

The Spruce Grouse is a rare bird of coniferous forests in Wisconsin and is found only in the northernmost counties. Most Spruce Grouse in Wisconsin are associated with black spruce–tamarack swamp complexes, also using adjacent upland jack pine, spruce, and, in winter, red pine (Worland et al. 2009, Anich et al. 2013a). In Minnesota, Spruce Grouse also use black spruce (Anderson 1973, Haas 1974), although some move from black spruce in summer to jack pine in winter (Pietz and Tester 1982). In Michigan and Ontario, birds have been reported to typically use upland jack pine and spruce (Robinson 1980, D’Eon 1997). Jack pine in Wisconsin, particularly 15–30 year old stands near lowland spruce, can hold good numbers of Spruce Grouse, particularly during the male display and wintering periods. However, most hens in Wisconsin that use upland jack pine from fall through spring appear to leave this habitat to nest in black spruce swamps (Anich et al. 2013b).

In winter, Spruce Grouse use areas within forests that have a dense canopy and few deciduous trees, and feed nearly exclusively on conifer needles (jack pine, white or black spruce, red pine; Crichton 1963, Anich et al. 2013a). Accumulations of their droppings on the snow can be a clue to their presence (Robinson 1980). During cold temperatures, Spruce Grouse can roost under snow (Robinson 1980). Mating occurs in spring with males performing “flutter-jump” displays (Lumsden 1961). Often males choose display sites on upland “islands” or the upland edge of conifer swamps, however some males display in the middle of black spruce swamps or upland jack pine stands (Worland et al. 2009, Anich et al. 2013a). Male display sites in Wisconsin were characterized by fewer small trees, more jack pine, very few broadleaf trees, and more canopy cover than nearby random points (Anich et al. 2013a). Hens with broods used a large area, most of which was typical black spruce swamp, but they also ranged into nearby mixed uplands that contained a relatively high density deciduous saplings such as alder, cherry, or hazel, presumably to provide concealment for young (Anich et al. 2013a). In the warmer months, Spruce Grouse forage on conifer needles (including tamarack), ground vegetation (especially leaves and berries of Vaccinium spp.), insects, and fungi (Crichton 1963, De Franceschi and Boag 1991).

Typical nest site is under a small black spruce, surrounded by bog Labrador tea, leatherleaf, and blueberry in the interior of a black spruce–tamarack lowland. Nest sites were found to have greater concealment by low vegetation than nearby random points (Anich et al. 2013b). Greater nest survival is associated with fairly dense (50–80% concealment) and uniform cover of vegetation around the nest (Anich et al. 2013b).

Habitat Availability

Spruce Grouse occur in low densities in northern Wisconsin with populations reported in Ashland, Bayfield, Forest, Iron, Oneida, Price, Sawyer and Vilas Counties (Scott 1943, Robbins 1991, Gregg 2006, Worland et al. 2009). Douglas, Langlade, Marinette, Oconto, and Taylor counties have had Spruce Grouse reports since 1980, but are on the edge of the range, and current status in these areas is unknown (Worland et al. 2009). Recent Spruce Grouse observations have primarily been within the North Central Forest Ecological Landscape. The Chequamegon-Nicolet National Forest and Vilas County Forest appear to hold the highest concentrations.

The volume of spruce (black and white) is currently increasing in Wisconsin, while the volume and growth rate of jack pine have decreased significantly (Wisconsin Department of Natural Resources 2010a, Wisconsin Department of Natural Resources 2010b). These species are also demonstrating increased mortality, which could be related to increased forest age, but may also be related to predicted negative effects of climate change (Scheller and Mladenoff 2005, Prasad et al. 2007, Wisconsin Department of Natural Resources 2010a, Wisconsin Department of Natural Resources 2010b).

Worland et al. (2009) observed that two centers of spruce grouse distribution (a western area in Sawyer and Ashland counties, and an eastern area in Oneida, Vilas, and Forest counties) are also regions with particularly high concentrations of upland and lowland coniferous forest. Other areas of the state, including Burnett, Douglas, and western Vilas counties have abundant upland conifer, but limited lowland conifer or limited conifer connectivity and have fewer to no spruce grouse.

Population Concerns

This is a state threatened species due to small population size and patchy distribution. Climate change and habitat modification appear to be the main threats to Wisconsin’s Spruce Grouse population. Patchy distribution and small population size in the southern portion of its range make the Spruce Grouse vulnerable to extirpation (Bouta and Chambers 1990).

A major threat is loss, degradation, and fragmentation of essential habitat. In Michigan, conversion of jack pine forests to deciduous species led to population declines (Robinson 1980). Harvest methods that result in black spruce converting to alder or northern white cedar, or upland jack pine or spruce converting to hardwoods will be detrimental to Spruce Grouse. Commercial forestry can make habitat conditions untenable for Spruce Grouse if large areas are clearcut and sufficient patches of young trees do not remain (Szuba and Bendell 1983). Stands that have been commercially thinned also showed reduced use by Spruce Grouse (Lycke et al. 2011). Logging of lowland spruce-tamarack swamps is likely detrimental as Spruce Grouse in Wisconsin used conifer swamps averaging 83 years old (up to 140 years old) and regrowth is often slow and now may be hampered by climate change (Anich et al. 2013a). Recurring insect and disease problems (e.g., spruce and jack pine budworm) may have significant negative effects on Spruce Grouse populations, and climate change could exacerbate effects of these outbreaks on trees.

Climate change is likely a major threat to the long-term persistence of Spruce Grouse in the state, as the conifer habitats they require are projected to recede northward with a warming climate (Scheller and Mladenoff 2005, Matthews et al. 2007, Prasad et al. 2007, Wisconsin Initiative on Climate Change Impacts 2011).

Nest survival in Wisconsin can vary from year to year, but is apparently good with 17/25 nests successful, (0.985 daily survivial rate; Anich et al. 2013b). However, estimated chick survival to adulthood is somewhat low, 1.0 young/female including all nest attempts (and 3 hens that did not nest), and predation seems to be high for adult males in spring and females in summer (Anich et al. 2013a, b).

Annual survival in Wisconsin was 54% for adult males, 40% for females, and 14–24% for juveniles (Anich et al. 2013b). Estimates of the rate of increase of the population of 0.65 and 0.67 suggest a declining population, but confidence intervals exceeded 1 (0.27–1.18), leaving open the possibility of a stable or slightly increasing population (Anich et al. 2013b).

Natural predators in Wisconsin are unknown, but probably include canids, hawks and owls, mustelids, and small mammals (Robinson 1980, Boag and Schroeder 1992). Relationship with predators needs more study.

Spruce Grouse are particularly vulnerable to hunting and exploitation because they are not wary of humans. Even though it is a non-game species in Wisconsin and has been since 1929, some accidental take by humans occurs (Scott 1943, Gregg 1994). It is difficult to estimate how many birds are shot during Ruffed Grouse season. Of 38 Spruce Grouse radiotracked during fall, one, a male, was shot during Ruffed Grouse season (N. M. Anich, unpub. data). Although likely some are shot every year, possibly impacting local populations, it is likely not a major population-level concern.

There is likely gene flow between Wisconsin birds and birds in the Upper Peninsula of Michigan. Although capable of movements of up to 11 kilometers (Boag and Schroeder 1992), the Wisconsin population is likely not connected to the Minnesota population. If populations are extant along the Brule River in Douglas County, Bibon Swamp in Bayfield County, or in Taylor County, they may also be reproductively isolated from the rest of the Wisconsin population. Issues of connectivity are currently plaguing Sharp-tailed Grouse and Greater Prairie-Chickens in Wisconsin, and thus management that causes similar fragmentation of conifer habitats on the edge of Spruce Grouse range could be harmful. Current genetic diversity of Wisconsin Spruce Grouse does not indicate problems at this time (George Barrowclough, pers. communication).

Recommended Management

Lowland conifer swamps should be retained, as most populations in Wisconsin are centered around these complexes, and many birds use black spruce year-round (Worland et al. 2009, Anich et al. 2013a). Preservation of black spruce swamps is especially critical because this is the primary nesting habitat in Wisconsin (Anich et al. 2013b). Caution is advised if harvesting occurs, particularly given possibly reduced regeneration due to climate change (Prasad et al. 2007). Tamarack appears to be a favored food in summer, but northern white cedar does not appear to be used by Spruce Grouse (Worland et al. 2009, Anich et al. 2013a).

Spruce Grouse can benefit from forest management designed to keep pockets of jack pine in earlier successional stages on the landscape. Highest densities of Spruce Grouse were found in jack pine stands 11–29 years of age, especially stands adjacent to black spruce swamps (Szuba and Bendell 1983, Anich et al. 2013a). For long-term maintenance of populations, a large area with a mosaic of black spruce/tamarack swamp and even-aged jack pine, or jack pine-spruce, including an array of different age classes, is probably ideal. Logging activities in suitable habitat should be constrained to August–February to avoid disrupting courtship, nesting, and early brood rearing.

Some Spruce Grouse used red pine, particularly 20–30 year old stands, in winter. However because red pine provides poorer habitat for male display sites and broods compared to jack pine, jack pine should be favored over red pine on sites near spruce swamps (Anich et al. 2013a). Upland spruce (white and black) near swamps was often used in winter. Balsam fir receives some use year round, but does not appear to be favored (Anich et al. 2013a).

Education of upland game hunters in the vicinity of Spruce Grouse populations should be used to reduce accidental take.

Research Needs

While a current DNR study should provide an estimate of current population size, population trend monitoring is needed. Population status at the edge of the Wisconsin range (Douglas, Taylor, Lincoln, Langlade, Oconto, Marinette counties) is unknown. Causes and factors affecting brood and adult mortality need further clarification. The effects of habitat patchiness and other landscape factors on dispersal and long-term site occupancy of Spruce Grouse needs further investigation. As climate change pushes the southernmost boundary of black spruce northward, identifying locations that represent climate refugia will be important to effectively directing conservation effort in conifer swamp ecosystems.

Information Sources

References

Contact Information

Revised date: 7/19/2013

Kreitinger, K., Y. Steele and A. Paulios, editors. 2013.
The Wisconsin All-bird Conservation Plan, Version 2.0. Wisconsin Bird Conservation Initiative.
Wisconsin Department of Natural Resources. Madison, WI.

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