Sounds
Spruce Grouse are among the most silent of all grouse, but they nevertheless have a number of calls used to warn of predators, to repel territorial intruders, to maintain brood cohesion, or to elicit brooding. In the subspecies franklinii, territorial males are notable for their wing-clap display. At the end of a short flight through the trees, the wings are brought together over the back so as to produce two sharp claps, about 0.5 s apart, loud enough to be heard by the human ear 150 m away. These territorial displays can sometimes be elicited by similar hand clapping, and can be used to detect male territories and estimate their density. Other non-vocal sounds include soft drumming by territorial males (a sound produced by the beating wings) and a tail-swish and a whoosh produced by the tail feathers in flight.
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“For sounds in winter nights, and often in winter days, I heard the forlorn but melodious note of a hooting owl indefinitely far; such a sound as the frozen earth would yield if struck with a suitable plectrum, the very lingua vernacula of Walden Wood, and quite familiar to me at last, though I never saw the bird while it was making it.”
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—Charles Sanders Peirce (1839–1914)