It was a warm, dry afternoon in mid-April when the forest fire began. Strong winds reached a smoldering ember deep within a slash pile, kindling flames to life. Soon the fire escaped the pile and raged out of control through stands of red pine and jack pine, rolling over the treetops in golden waves. It burned wildly for one day and into the night before succumbing to the efforts of firefighters and calmer winds. But it was more than a week before all the residual hot spots were put out. The incident was named the Palsburg Fire after the Palsburg Forest Road where the fire originated, and it burned 4,500 acres in the Beltrami Island State Forest in northwestern Minnesota.
Once the fire was out, the Department of Natural Resources quickly assembled a plan to begin salvage logging any harvestable trees that were still standing. The DNR would sell what it could and put the proceeds back into the state forest, planting and planning for the future.
DNR staff wondered what effect the fire and sudden change in habitat would have on birds. Gretchen Mehmel and Charles Tucker, the manager and assistant manager, respectively, of Red Lake Wildlife Management Area, devised a plan to find out. The study area was perfect due to its large size and accessibility, and the study would be the first in the state to look at avian responses to a fire during the year in which it occurred.
Mehmel and Tucker decided that a point-count study would be used to monitor bird use in the burn area. Fifty points were selected within the fire perimeter; another 50 were identified in the adjacent unburned forest. Each point is entered into a GPS unit, and these same points are used every year of the study. Counts are conducted in the early morning, as this is when the breeding males are calling the most. During the five-minute count time, the surveyor listens and looks for birds and records them on a data sheet. An experienced birder was needed to perform the counts, and that's where I came in.
It was the opportunity of a lifetime. I have been conducting breeding bird surveys for the U.S. Fish and Wildlife Service for years, but I have never been involved in a habitat study like this. So I arranged to take a couple of days a week off from my regular job and headed out into the forest to count birds.
Teeming Life. I began surveying in early June in the lush forest outside the burn. How exhilarating it was to be out in the woods in early summer listening to the songs of warblers, vireos, flycatchers, and sparrows again!
After a few days of point-count surveys outside the burn area, I moved inside the fire's perimeter. I did not expect to document many species here, thinking that the burn area would be a vast wasteland of burnt pines and, in the cutover areas, charred and lifeless prairie. When I got out of the truck at the first designated point inside the burn, my senses were immediately overwhelmed. It was five weeks after the forest fire, and the area was teeming with life. The air had a fresh, earthy aroma tinged with the smoky odor of a lingering campfire. Trees and undergrowth charred coal black contrasted drastically with the bright green of new plant growth springing up from the forest floor.
A northern flicker, breast feathers wet from the morning dew, was foraging hungrily for ants. Soft gray mourning doves strutted through the rubble picking at seeds and insects, heads bobbing. American goldfinches hopped from low branches to the ground and back again, their lemon-yellow feathers glowing in the morning sunshine. Although loggers were working a mere quarter-mile away, territorial male birds seemed oblivious to the noise and were singing their hearts out, as if trying to outdo the loggers' whining saws and rumbling tractor engines. What surprised me most was that they were here at all in this altered landscape, so very different than their breeding grounds last summer.
As I drove on to the next stop, a flash of color caught my eye. It was the orangey red coat of a male red crossbill. Cones of the red and jack pine, opened by the heat of the fire, provided an abundant food source for the crossbills, who were now gorging themselves on the pine nuts in great flocks. I heard the soft "chek" call of a black-backed woodpecker nearby, as well as the sharper "peek" calls of the hairy and downy woodpeckers, all drawn here by a feast of grubs and beetles residing under the bark of the dead pines.
Visits to the burn on subsequent mornings were full of surprises. Vesper sparrows, normally found in fields and grasslands, were common in the cutovers, now newly transformed open spaces. Eastern bluebirds perched atop slash piles, darting out to catch insects. Brown thrashers and alder flycatchers, normally found in dense thickets, sang from singed pines too small to harvest. Killdeer scuttled about like wind-up toys. A western meadowlark belted out its bubbling sweet song, hoping to entice a mate to this new land of plenty. At the edges of the burned forest, scarlet tanagers were easily visible as they perched in needleless pines, and olive-sided flycatchers called from lowland brush, close to where the fire had run its course.
After one season of point count studies, we learned how quickly birds adapt to change caused by a fire. A subsequent bird survey was planned for the summer of 2016.
Woodpeckers in Winter. I was drawn back to the forest the first winter after the fire, not by a scheduled bird survey but by the lure of the black-backed woodpeckers. Were they still out there, and in what numbers? On a bright sunny day in January, I drove to the forest and skied into a stand of burned red pines. It did not take long to find a black-backed woodpecker working the trees, flaking bark off in all directions. Her tail was braced stiffly against the trunk as she positioned her body to get at the tastiest grubs hidden beneath the bark. Satisfied she had excavated all available food from one tree, she turned her head, looked over her shoulder, and flew on to the next tree.
I stood on my skis, camera in hand, and heard tapping all around as hairy, downy, and black-backed woodpeckers hammered and drilled into the pines. The snow was a sparkling white canvas striped with blue-gray shadows cast by the trees in the low light of the winter sun. Tracks of bobcats, deer, wolves, and mice crisscrossed the newly fallen snow. Once again, not in summer but in the dead of winter, I felt as if a magical spell had fallen on this place.
Nature's Stage. By early June of 2016, 13 months after the fire, most of the bark had been stripped from the dead pines by the woodpeckers. The trees now stood bare, blond and needleless, while ferns, wildflowers, and blueberry plants heavy with fruit grew luxuriantly below in soil rich with nutrients returned to the earth by the fire. Loggers had harvested what trees they could before decay set in, yet about half of the burned pines still stood uncut, providing prime habitat for cavity nesters such as black-backed woodpeckers. Indeed, several nesting pairs were discovered that summer.
I began the second season of bird surveying in the Palsburg with great excitement and anticipation. It did not take long to discover the atmosphere had mellowed at those survey points inside the burn perimeter. The gregarious red crossbills, having filled up on pinecone seeds released by the fire the previous summer, had dispersed and returned to their nomadic lifestyle. That summer I saw just one flock near a live grove of red pines, chattering noisily as they flew overhead.
The crossbills weren't as plentiful, but other bird species moved in with enthusiasm and exuberant song as they staked out breeding territories. From a tall leafless tree at the edge of a meadow erupted bird song, the thin but sweet notes of an indigo bunting. That morning in the predawn light, the bird appeared black silhouetted against the peach-colored sky as it moved back and forth between the meadow and the tree, vocalizing. I watched as the first rays of the sun touched the bird, transforming it into a cerulean blue beauty.
The western meadowlarks, vesper sparrows, and eastern bluebirds had returned, having found suitable breeding habitat the previous season. A newly arrived male Brewer's blackbird, with its yellow eyes and its ebony and iridescent midnight blue feathers, called to his mate from a small jack pine on the edge of a clear-cut. An eastern kingbird chose a slash pile as its vantage point, catching flying insects in quick bursts and dramatic chases. The low buzzing call of a clay-colored sparrow traveled across the field as a male threw his head back and belted out a song.
Nature's stage had also been well set for the Wilson's snipe. I heard many of them winnowing overhead, wind rushing through their tail feathers as they flew. I squinted hard to make one out high in the sky, a tiny dot with stubby wings flapping furiously just before dropping into a dive.
Bustling Biodiversity. The biodiversity created by the dramatic change in landscape after the Palsburg Fire was astounding. While some larger clear-cuts had come back in native grasses, such as big bluestem, and provided a prairie-like habitat for birds, smaller clear-cuts adjacent to live deciduous forest had grown back in young aspen and dense brush. A symphony of birdsong poured out of these thickets: the cheerful rolling notes of a mourning warbler, a chestnut-sided warbler calling "pleased-pleased-pleased to meetcha," the slower rambling whistle of a yellow-rumped warbler, and a cacophony of gurgles and chirps sung gaily by a gray catbird. White-throated sparrows, chipping sparrows, and song sparrows joined in the orchestra. From within the forest's edge came the sorrowful call of an eastern wood pewee, distinctive and shrill. Up to 20 different species of birds could be heard at a single stop.
The Palsburg Bird Survey will continue annually for the next three years, then twice more at five-year intervals. The first season of data has shown which bird species move into burn areas immediately after the disturbance—most notably red crossbills and black-backed woodpeckers in the burned pines, vesper sparrows in newly opened fields, brown thrashers in partially burned brushy areas, and indigo buntings and eastern bluebirds at the forest-field edges.
The second season provided information on bird species that have stayed to breed in newly created habitat. Among them are cavity nesters like the black-backed woodpecker and the eastern bluebird. The survey has also shown which species have moved into what is now grassland, lowland brush, and wet meadow: the Brewer's blackbird, for example, along with the western meadowlark, Wilson's snipe, and the eastern kingbird.
I look forward to surveying these points in the years to come, documenting nature's rebirth after a forest fire and discovering how bird species adapt to these changes.