Killer Babblers revisited

I received this from Caroline Blackmore at Southern Cross in regard to the ‘Killer Babblers’. It may have already been posted and if so I apologise.

Babblers often form same-sex coalitions to disperse (males more often than females) and in my thesis I speculate that a coalition will kill the incumbent same-sex line to take over a territory; and, if the coalition partner are close in age, will kill each other off once they’ve successfully acquired the territory. Although I never witnessed it there was indirect evidence e.g. in a group of three, a dominant male and his younger helper brother would frequently be replaced by a new dominant male and his younger brother. I couldn’t rule out divorce as I didn’t see what happened, but it did seem unlikely that both males would spontaneously die at the same time, to be replaced almost immediately by a new coalition. Also they could have just been driven off but I never sighted them again over a large area. I also had a very telling incident where two unrelated females of about the same age established a new territory on a reveged site. They held it for ca. a year, then within a week of a male joining them one of the females was found dead. In another cooperative breeder, the Arabian babbler, female coalitions will kill to take over a territory, and male coalitions initially share paternity but eventually kill each other off until there is only one.