J P Myers 1980 Calidris melanotos NARL, Barrow, Alaska 2 July (Contd) The pitch of the call may change as β goes from L16C to L16C/2. When the γ reaches the β + goes beyond him he often changes to R6 (see below). For strange variant of this interaction see McLafferty's entry to C. melanotos phenology 22 June 1980. Involves unusual γ erect posture and possible mutual ant cupping by β. See also Sheppard 1978 and Myers 1976 Rolling Group - R6 - given in close proximity to γ, usually in pursuit on ground, 5-15 cm away + moves rapidly. Usually from TC group but can start de novo. Sorsdal: "How do they do that?" While he does R6 the γ usually keeps her tail toward him + changes direction constantly. He may face her or stand broadside. Posture during R6 - laterally compressed like a rail with tail cocked. Sorsdal: "Looks as though his throat sac is fibrillating" with the sac bouncing at an incredible pace. Various parts contracting at the same time. Head is moving up and down. The R6 actually has two vocalizations - one is the R6 itself, the fibrillation, in an insane repeated klec klec klec (hardly do it justice). This sound continues nonstop. Superimposed on that is ahoot at periodic intervals so that the overall effect is as pitelén describes: craw craw craw klec klec klec craw craw craw klec klec klec where the craw is actual composed of klec and hoot. The birds head moves up and down during the craw craw craw phase, which lasts 2-3 sec each time, as does klec klec klec. If R6 persists he gets behind her and enters SQUAWK which is an obnoxious wheying sound, almost a squeal or a breathy hiss. As he does this his neck is extended fully until he begins to flutter his wings - one wing then both wings. It is 5-10 cm from her + gets close enough to step onto her back. The average SQUAWK is really two calls - a wheeze alternated with