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Electronic Supplementary Material

Video caption

Video 1. Adult peacock displays. This video clip begins with a male at the Bronx Zoo

(BZ, May 2008) displaying his train with no females in view, then continues with a male at the Los Angeles Arboretum (LAA, March 2008) displaying to a female, first performing the wing-shaking display followed by train-rattling once the target female is in front of his erect train. The vibrating feathers can be heard during the train-rattling display.

Model presentation methods

Table S1 provides further details of the sampling methods for the model presentation experiment. We conducted this experiment on 17 different adult males. After successfully completing one trial for a given male, we tried to perform the next trial at the same period of the day (AM or PM) with that male, presenting the model on the opposite side. We were able to run all four trial types with only 2 males; we ran three trials with each of 2 other males, two trials with each of 6 males, and only one trial with each of 7 males

(Table S1), for a total of 33 trials (AM-EAST = 9, AM-WEST = 10, PM-EAST = 8, PM-

WEST = 6 trials). 2

Table S1. Sampling for model female presentation experiment, with type of trial listed by individual male (n=17).

AM PM male EAST WEST EAST WEST 1     2     3    4   5   6   7   8    9   10   11  12  13  14  15  16  17 