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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123. No. 4. December 2011 
Perpendicular distance (m) 
FIG. 2. Detection probability of Black- fronted Piping Guans as a function of the distance to the observer. The columns 
represent the number of detections in different distance classes, and the line represents the fit detection function (Software 
DISTANCE 5.1). 
(Fig. 3). We considered a population as a set of 
individuals living in the same region which had no 
interaction with other individuals living in other 
regions. 
The inshore islands and the contiguous protect¬ 
ed areas of Paranapiacaba massif had the highest 
density estimates (DE) of this species (> 10 
observations and >2 groups/km 2 . Table 2). The 
highest number of observations and DE were 
recorded from Ilhabela Island (29 encounters or 
41% of the records, DE = 8 groups/km 2 . 
Table 2). 
