In Fly Like a Bird 3
Mates, by broadcast definition, is anyone who helps a nest by gathering twigs for whoever owns the nest. The "social happenings" part is what separates mates from nest helpers.
Difference Between Mates
Mates are vaguely defined players that are either in a relationship with the other bird, or a bird who helps only the nest of a partner. They can be both. Some mates, upon deciding on their mate, may change their name to "XlovesY" or "loveY", "Yslover", or maybe even "Ysmate". A common saying among newbies is "I need a mate". You don't actually need a mate to build a nest or to feed chicks.
While nest helpers can be hit-and-run twig throwers, mates are often more intimate with the nester.
Sometimes, "mate" is simply shorthand for "boyfriend/girlfriend", especially in role play.