Effects of pairing Thamnophilus ambiguus males with females on the behavioral responses by males to playback

The behavioral responses of the Sooretama Slaty-antshrike (Thamnophilus ambiguus) to playback were tested in a Restinga (sand-coastal plain) area in southeastern Brazil. Field data were collected for seven mornings, from 5:30 h to 11:00 h. Frequency data and the time period between playing the species' song (playback) and the sighting of individuals were recorded by the observer. The following parameters related to behavioral responses to playback were recorded: 1) the bird flew to a visible roost but not sang (sighting); 2) the bird sang as response to playback (vocalization) and; 3) the bird sang and approached to the observer (bird approaching). The time of response to playback of males paired with females was significantly shorter than that of unpaired males, albeit with no significant difference in the sighting and bird approaching frequency. In conclusion, males paired with females become more aggressive and show a faster territorial defense response than solitary males.