Spruce Grouse (Dendragapus canadensis)

Spruce GrouseSpruce Grouse distribution map

Status/Protection

Population Information

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. Found only in the northernmost counties, it is restricted to areas of early-successional jack pines, upland spruce and spruce/tamarack bogs ( Robbins 1991). In those areas where it has been well-studied, it often uses dense coniferous stands, with 2500 to 3500 stems per hectare (per 2.5 acres). Unburned islands of bog forest within burned or managed jack pine are used to a lesser extent (Boag and Schroeder 1992). Spruce Grouse utilize coniferous habitats until lower branches begin to self-prune due to canopy shading and seem to prefer landscapes with a juxtaposition of upland short-needled conifers and lowland conifer stands.

In winter, Spruce Grouse retreat to the most protected, densest areas of these forested habitats. These grouse use snow banks for winter roosts, and move to more open areas of forest when snow melts in the spring. Accumulations of their droppings in snow bank roosting areas are a clue to their presence, especially in early spring ( Robinson 1980). Mating occurs in spring with males using standing trees to conduct their courtship “flutter flight” displays (Robinson 1980). The males choose territories based on canopy cover and density of stems, with less shrub cover, while females choose foraging areas with diverse shrubs and herbs. In nesting areas in Ontario, jack pines from 4-6 meters (13-20 feet) in height are preferred by Spruce Grouse, along with a secondary layer of shrubs ( Szuba and Bendell 1983).

The Spruce Grouse feeds almost exclusively on the needles of jack pine, white or black spruce during the winter and conifer needles (including tamarack), along with berries (especially Vaccinium sp.), insects and ground vegetation in summer (Boag and Schroeder 1992).

Habitat Availability

Spruce Grouse occur in low densities in northern Wisconsin with populations reported in Ashland, Bayfield, Forest, Oconto, Oneida, Price, Sawyer and Vilas Counties (Gregg 1994, WBBA Atlas Project). Recent Spruce Grouse observations have primarily been within the Northern Highland and North Central Forest Ecological Units. Within these units, the Chequamegon/Nicolet National Forest, Northern Highland/American Legion State Forest and Vilas County Forest appear to hold the highest concentrations.

In Wisconsin, decreases in jack pine acreage (down 28% between 1983 and 1996 to 387,000 acres) and lowland coniferous forests (down 15% in the past century) important to Spruce Grouse are not favorable for maintaining or improving populations (WDNR Forest Inventory, Snetsinger and Ventura n.d.).

Population Concerns

Patchy distribution and small average population size in the southern portion of its range make the Spruce Grouse vulnerable to extirpation (NatureServe 2005). The dominant threat is loss, degradation and fragmentation of essential habitat. Since Spruce Grouse require earlier successional stages, logging per se has not always been detrimental to this species. In Michigan, conversion of jack pine forests to deciduous species led to population declines (Robinson 1980). 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). Periodic fires provide ideal habitat, in a mosaic of “islands” or patches that re-grow and are used by higher densities of Spruce Grouse for 10-15 years ( Boag and Schroeder 1992). However, fire has infrequently been used as a management tool for this species. Reoccurring insect and disease problems and conversions in short-needled conifer forests in Wisconsin may have significant effects on Spruce Grouse populations as habitat loss occurs.

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 (Gregg 1994).

Recommended Management

Spruce Grouse need short-needled conifer forests, especially fire-maintained forests that can create optimum habitat conditions. Spruce Grouse are found at highest densities for only 10-15 years post-fire ( Boag and Schroeder 1992). In the absence of fire, manipulation of jack pine stands to create early-successional age classes of trees will be necessary to maintain large enough tracts of suitable habitat. As these age classes of jack pines disappear from extensive forested areas, Spruce Grouse will and do decline with them ( Robinson 1980). Patchy 15 – 30 acre clearcuts in jack pine types within managed forests can help this species ( Szuba and Bendell 1983).

Spruce Grouse can benefit from forest management designed to keep pockets of short-needled conifer habitat in earlier successional stages on the landscape. For long-term maintenance of populations, a large area with a mosaic of even-aged stands of jack pine and jack pine-spruce including an array of different age classes is probably ideal (Boag and Schroeder 1992). In areas of fragmented habitat enlarge smaller patches or develop connecting corridors of habitat among patches. A key to good habitat management is to provide a continual supply of extensive areas of dense conifer stands of trees with live branches 0 – 4 meters above the ground (NatureServe 2005).

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

Research Needs

Monitoring for this species is probably insufficient at the present time, given its threatened status. Research into links between forestry practices and population viability in WI is needed, although this has been studied in Canada and some US states ( Boag and Schroeder 1992, WDNR online Endangered and Threatened Species Factsheet). The effects of habitat patchiness on dispersal and long-term survival of Spruce Grouse needs further investigation (NatureServe 2005).

Information Sources

References

Contact Information

Kreitinger, K. and A. Paulios, editors. 2007.
The Wisconsin All-Bird Conservation Plan, Version 1.0. Wisconsin Bird Conservation Initiative.
Wisconsin Department of Natural Resources. Madison, WI.