Figure 2
From: Sex differences in behavioural and neural responsiveness to mate calls in a parrot
Call response in experiment 1.
(a) Before the behavioural tests, males and females were paired for 5 weeks and then separated, without auditory/visual stimulation from the mate. Birds were unfamiliar with their mate prior to the pairing but they could memorize their mate’s call during the pairing period of 5 weeks. Each male was given three behavioural tests at 0 month (m0), 1 month (m1) and 5 months (m5) after separation. (b) Mean (+ s.e.m.) call-response ratios in experiment 1. The call-response ratio was calculated for each individual as the number of calls in response to the mate’s call divided by the grand total (i.e., the number of calls to the mate’s call and that to the unfamiliar call). Asterisks denote a significant difference from chance level (dashed line). The call-response ratio at m1 was significantly lower than 0.5 (**P < 0.01), indicating that males responded to mate calls less than to unfamiliar calls.
