Bell miners (Manorina melanophrys) feed primarily on the lerps and nymphs of psyllids, and they defend communal territories against other bird species. As bell miners were removed exprimentally from a psyllid-infested patch of eucalypt forest, birds of 11 other species moved in to feed on psyllids and within 4 months they eradicated the infestation. This shows the ability of other birds to control these insects in the absence of bell miners and the value of interspecific territoriality to bell miners.