Spatial Relationships of Neighboring Male Ruffed Grouse in Spring

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Abstract
Locations of 5 drumming male ruffed grouse (Bonasa umbellus) were recorded with an automatic radiotracking system on the Cedar Creek Natural History Area in east-central Minnesota [USA] during spring 1970. Overlap of the ranges of 2 adjacent males was found in 17 of 23 wk, and mutually occupied areas varied from 0-3.21 ha (.hivin.x = 0.88). Size of the overlapping area was negatively correlated with distance between activity centers and positively correlated with mean size of the 2 neighbors'' ranges. A strong tendency was found for differential use of overlapping 0.026 ha gridsquares. Male grouse usually avoided their neighbor''s side of an artificial boundary line, suggesting that real territorial boundaries may have existed. Values of an index of interaction potential (based on locations .ltoreq. 2 min apart) showed that adjacent males could have displayed at close quarters or fought in most (78%) cases. One of 2 vacated territories was reoccupied by an unmarked juvenile male.