Check out this group of Red-backed Fairy-wrens. These are the little guys I study. Allopreening or allogrooming likely serves multiple functions - the removal of parasites and the strengthening of the relationships with the group. There's a good chance these guys are related. The one with the single light blue band managed to break off it's two other color bands but I think it's the mother from the previous breeding season. The two unbanded birds are likely her offspring. Watch the female grab a caterpillar from the branch next to them about 3/4 of the way through the video.