Monday, February 6, 2012

The Disappearing Adirondack Spruce Grouse

The spattering of sizable tracts of boreal forests that remain in the Adirondacks serve as home to several species of birds that have evolved the ability to survive in northern taiga woodlands. Among the feathered creatures that are well adapted for a life in lowland stands of conifers is the spruce grouse (Falcipennis canadensis), a dark colored bird viewed by some as being as much a symbol of the Great Northwood’s as the moose.

As its name implies, the spruce grouse inhabits those softwood forests dominated mainly by spruce; yet not all spruce forests serve as home to this northern bird. High elevation forests that cover the upper slopes of our tallest peaks are not as suitable as lowland locations despite the similar presence of spruce and balsam fir. Because higher altitudes are more frequently buffeted by strong winds, the microclimate that exists there is more adverse than the one that characterizes sheltered, lowland settings.

Unlike most other fowl, the spruce grouse spends a considerable amount of time among the branches of trees, and windy conditions can seriously impact its feeding and roosting routine. Also, rime ice often encrusts the foliage of the conifers at these higher elevations when moisture-laden clouds sweep over the summits. Although this icy covering on all the trees of a hillside creates a spectacular winter image for hikers, it greatly interferes with the spruce grouse’s ability to forage.

Relatively small patches of spruce and balsam fir that are separated from other boreal woodlands by a fair distance are not considered to be ideal habitat either. These small, widely scattered clumps of spruce and fir are often too isolated for this bird to locate when young adults begin to search for a territory in the spring. It has been shown that the spruce grouse tends to claim a territory of about 15 to 50 acres during the breeding season. An area much smaller than this may seem great, but it could simply be too confining for this bird.

Sizeable stretches of spruce and fir forests in which the soil is damp are considered to be ideal for the spruce grouse. Also, places in which numerous small openings of less than half an acre in the forest canopy are scattered across the terrain are known to be highly attractive to this bird. Such small clearings are perfect for the growth of blueberries and other small shrubs that can provide this bird with fruit during the mid-summer.

Small clearings in such damp locations also tend to allow for the growth of tamarack, a conifer that is used by this grouse during the autumn. Researchers have noted that as colder weather becomes more common in fall, the spruce grouse concentrates much of its needle nibbling time on the soft foliage of tamarack before these flexible structures drop to the ground. It is unknown what impact tamarack needles have on their physiology, but it is at this time of year that the digestive system of the spruce grouse changes, in order to better accommodate its winter diet of spruce needles.

Along with developing added length to its intestinal tract to deal with the processing of spruce needles, the crop of the spruce grouse also expands greatly in size with the approach of winter. In far northern latitudes, this bird is only able to forage among the branches of trees for 6 to 8 hours a day. Prior to sunset the grouse ingests a sizeable quantity of food that it temporarily holds in its crop and gradually releases into its digestive system throughout the night. It is reported that the crop, a sac located at the end of its throat, just before its gizzard, can hold one-tenth of the bird’s body weight in food.

The dark plumage of the spruce grouse allows this bird to blend well into the darkened background that commonly exists in evergreen forests. As a rule, its protective coloration is so effective that few predators are able to notice it as it perches among the twigs and branches of a spruce-fir thicket. Because this bird has learned to depend on its camouflage for protection, it tends to remain motionless when a large animal, like a human approaches it.

As some birds, like the wild turkey, expand their range northward into the forests of the Adirondacks, others, like the spruce grouse appear to be retreating from the region. As our climate warms and our forests mature, the wildlife communities they support will also change. Perfectly static environments are rare as changes are inevitable. It will be a shame to have the spruce grouse disappear from our landscape, however, I am very fearful that it may become only one of many forms of life that will be unable to continue to exist in the future here in the Adirondacks.

Photo: Female spruce grouse, courtesy wikipedia.

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Tom Kalinowski is an avid outdoor enthusiast who taught field biology and ecology at Saranac Lake High School for 33 years. He has written numerous articles on natural history for Adirondack Life, The Conservationist, and Adirondack Explorer magazines and a weekly nature column for the Lake Placid News. In addition, Tom’s books, An Adirondack Almanac, and his most recent work entitled Adirondack Nature Notes, focuses on various events that occur among the region’s flora and fauna during very specific times of the calendar year. He also spends time photographing wildlife. Tom’s pictures have appeared in various publications across the New York State.

3 Responses

  1. Paul says:

    Any animal that has evolved to live on a bunch of spruce needles is one tough cookie and deserves some help.

    Tom do you think that increase in coyotes in some areas (especially these timber tracts that have good SG habitat) has had an effect on the bird? I guess the first question is my assumption correct? Are there more coyotes? Seems like it to me.

  2. Tom Kalinowski says:

    Hi Paul: I am of the opinion that our current, relatively high, coyote population does not have much of an impact on this bird. Because it spends so much of its time off the ground, other predators, like the marten and fisher are believed to be bigger threats to the spruce grouse than the coyote.

  3. Paul says:

    Tom,good point. As I understand it the Fisher population has been steadily on the rise. I know that this was one rational for now extending the Bobcat seasons since the Fisher is doing better. Not so sure about Martens. I have seen a few of those around. That is a neat looking animal (one I saw looked pretty orange).

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