Spruce grouse inhabit northern conifer forests and range as far south as the northern-most Wisconsin counties.
A canary of Northwoods change
Spruce grouse may send a sensitive signal from our northernmost counties.
David L. Sperling
Armed with a digital recorderand small noose-like loops at the end of metal poles, DNR wildlife technicians aim to round up information about a forest grouse that may indicate how subtle changes in northern forest climate affect woodland wildlife. The spruce grouse, Falcipennis canadensis, is a state-threatened bird of the northern forest that only ranges across the northern tier of Wisconsin counties concentrated in the Chequamegon-Nicolet National Forest.
"Wisconsinís spruce grouse population is fairly small, sparsely distributed and inhabits conifer species such as jack pine, black spruce, white spruce and red pine," says Karl Martin, project leader and chief of DNRís wildlife and forestry research. "These tree species are likely to decline under moderate climate change, and that makes our spruce grouse population an ideal candidate to provide early signs of climate change similar to the canary in the coal mine. Even moderate warming could result in the extirpation of spruce grouse in Wisconsin.
Mapping spruce grouse range and movement is part of a cooperative research project with the U.S. Forest Service.
The chunky, compact, black and white speckled bird, struts and plods along the wooded edge during mating season in late spring as the last snows are melting, stopping to quickly fan out its tail feathers and displaying for a potential mate. The maleís fanned black tail feathers with whitish spots form a pointy curve and look a bit like a miniature sage grouse when viewed from the rear.
Monitoring started in Wisconsin in April 2006, and radio-tracking/telemetry studies started in May 2007. Wildlife researchers attract both sexes of spruce grouse by playing recordings of the femaleís mating call, a series of grunt and hoot-like sounds called a cantus. The male responds with a flutter flight that sounds a bit like distant thunder, says DNR Wildlife Research Technician Mike Worland. The male grouse are drawn out in the hopes of attracting compliant females. The hens are curious about other females in the area. One male will mate with several females. Following breeding in late April through early June, the females lay 5-7 eggs in a ground nest under dense cover. The females provide all the parental care for the young chicks.
Spruce grouse are so confident that their cryptic feather pattern provides good camouflage in the brushy forest edge that they do not run away from people. That confidence leads to their nickname of "fool's hen." Researchers can get very close, within 10 feet, and trap or noose the birds.
"It's still quite a challenge to gently get a noose around their neck," Worland says. Delicate radio transmitters about the size of a quarter are then attached to the grouse like a wire necklace and will send a signal for up to a year that can be detected up to a half-mile away, depending on the terrain and whether the birds are on the ground or in the top of a tree. Researchers are using the information to track the grousesí range, movements and habits.
"We've collared a total of 25 spruce grouse near Clam Lake; we currently have 12 on the air and plan to collar several more this spring," Worland says.
In winter, spruce grouse hang out in trees feeding on spruce needles and buds. In the evenings they roost in snow banks. During warmer weather, their young pick at ferns, insects, snails, fungi and berries on the forest floor.
Most spruce grouse donít migrate far. They often will walk a mile to a few miles between summer and winter range.
Wildlife biologists also are investigating other factors that might explain what management steps might bolster spruce grouse populations here. Itís possible that these grouse are subject to more predation at the boreal forest fringe by owls, goshawks, marten, fisher and foxes.
"Spruce grouse are at the extreme southern edge of their range here," Worland explains. "We donít know how predation-caused mortality here compares to other regions, but this is a boreal bird, and habitat is certainly less available in Wisconsin compared to the bulk of their range. We usually find them in large stands of coniferous forest, particularly black spruce swamps. A smaller stand of conifers surrounded by deciduous forest probably wonít support these grouse," Worland says.
They clearly prefer lowland conifers like spruce, pine, fir, larch and tamarack. One parcel of ideal habitat a few miles northeast of Conover is called Spruce Grouse Swamp State Natural Area. The mix of sedge meadow, muskeg and swamp surrounded by a dry, sandy boreal forest of jack pine, red pine and spruce is favored by this grouse, as well as gray jays, boreal chickadees, black-backed woodpeckers and Connecticut warblers.
David L. Sperling edits Wisconsin Natural Resources magazine.