Fig. 6From: Previously unknown behavior in parasitic cuckoo females: male-like vocalization during migratory activityChanges in the amount of neck region inflation while emitting male-like call. The figure illustrated a sequence of three notes of three-note male-like call of female F1. The amount of inflation was estimated by measuring the area of the neck region as indicate by red dotted lines a; the enlargement of the neck region was estimated as the percentages relative to minimal inflation, i.e. before and/or after calling b. Three notes are shown spectrographically in the bottom panel cBack to article page