"Ktaadn, and the Maine Woods" from Sartain's Union Magazine: “The Wilds of the Penobscot" (July 1848: pp. 29-33); “Life in the Wilderness" (August 1848: pp. 73-79); “Boating in the Lakes" (September 1848: pp. 132-137); “The Ascent of Ktaadn" (October 1848: pp. 177-182); “The Return Journey" (November 1848: pp. 216-220)
Thoreau quotation
The sharp whistle of the blackbird, too, is heard like single sparks or a shower of them shot up from the swamps and seen against the dark winter in the rear.Journal, 2 March 1859