 In addition to their use as weapons , both sexes of the Rodrigues solitaire also used their wings for communication . The wings could create low @-@ frequency sounds for communicating with mates , or to warn rivals , but it is unknown exactly how this sound was created . The sound could be heard 200 yards ( 182 m ) away , and this may therefore be the size of the territory of an individual . Other species of birds are also known to use their wings to create sounds that attract mates or mark their territory . 
