When the Oaks are in Bloom

Birds of the Sterling Barrens                              26 May 2018

Purple Finch

Golden-winged Warbler

Aldo Leopold wrote,"Poor land may be rich country, and vice versa".  The Sterling Barrens of Polk County, Wisconsin are a fine example of Leopold's verse.  The landscape, sculpted of glacial sands, stands in stark contrast to all around it.  To enter the Sterling barrens from the east is to drop down from high, fertile, black soil farm fields into an ancient lake bed of arid, golden sand that spans for miles and miles.   The agriculture quite suddenly stops, and the wildlife dramas unfold endlessly there after in the sand country that supports blueberry, sweet fern, and the most durable and adaptable species of trees.  It is a place of jack pine, pin oak, red oak, Hill's oak, choke cherry and hazel brush.  In wet areas, aspen trees grow and wildlife oases flourish.  Because it borders the Saint Croix River, and because it is nourished by the Trade River, animals are remarkably abundant in the barren country.  Service berry, hazel nuts, aspen buds, and acorns feed an incredible diversity of birds and mammals.  From the sand, life abounds. 

In the Sterling Barrens, land is valued in many ways.  Forty-acre blocks of private land are sprinkled into the plat book here and there, many with small deer shacks and two-rut sand roads leading into mature and even sterile stands of jack pine and oak.  Other places are public lands' battle grounds against an invasive killer known as oak wilt, and big sections tell the tragic story with stump fields and slash piles.  Those places are infants in secondary succession, promising a world of hazel, aspen, and young forest in the years to come.  Some places, especially those fed by water, have always been difficult on people.  They are as wild as they have always been, crossed over by hundreds of game trails and rich in sedge meadows, low aspen forests, alders, and pockets of deep wetland.  Because of its vast acreage, this region functions contiguously as an important, highly functioning forest ecosystem, providing well for many uniquely adapted specialist species.  The birding is simply amazing.

Golden-winged Warbler

The two birds featured here do very well in this landscape.  Purple Finches thrive in areas with older jack pine and openings with dead trees, especially near the rivers. Golden-winged Warblers nest in the more open habitats adjacent to older forest, and the Sterling Barrens provides all of the best examples of this warbler's ideal.   In wet areas, Golden-winged Warblers utilize aspen and alder wetlands adjacent to islands of older trees.   In managed forest areas and oak wilt management areas, Golden-wings use sunny openings filled with Hill's oak, service berry, and chokecherry, especially in openings adjacent to older forests of the Trade River and the Saint Croix River.  In the world of Golden-winged Warblers, the Sterling Barrens represent a rich and valuable stronghold.  Nearly 25% of the world's population of Golden-winged Warblers breed in northern Wisconsin, and some of the highest breeding densities in the state are found in the Sterling Barrens.

To spend a dew-soaked morning in the barrens, greeting the sunrise and dawn chorus with a mug of coffee, wet pant legs, and a relaxed and happy yawn is good living.   Awake at 3 AM, arriving to the chorus of Whip-Poor-Wills in the dark, and watching the indescribable beauty of daybreak in this birding paradise, I realize that days of this quality are all too easy to count and should happen so much more often.  As the sun climbs higher into the sky, I return to the sand roads with soggy shoes and vow to return soon.

All images were made using a Canon 7D Mark I with a Canon EF 400mm f5.6 L lens.  I was able to shoot hand-held in the direct front-lighting of a clear and pure sunrise. The birds, while photographed well, own an even more impressive canvas in my memory.